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How can I avoid incomplete WMS layers when exporting large maps in QGIS 2.6?

How can I avoid incomplete WMS layers when exporting large maps in QGIS 2.6?


I have a QGIS 2.6 project with around 20 vector layers and an WMS layer (working on Ubuntu 14.04). WMS rendering works OK, although a little bit slow, and exporting A4-size maps also works properly (both to jpg and pdf), but the thing gets tricky when trying to export my final-size map, almost an A0.

Most of the time, some of the tiles of the WMS don't appear in the resulting pdf or jpg (see image below). However, I did export a large a week ago. In fact, the map I cannot export now is exactly the same I printed before, after querying one of the layers.

I have tried several "work-arounds":
* Print to a pdf printer, instead of exporting it. Same result.
* Erase the WMS layer and define it again, from scratch. * Have deleted the map from the composition and defined it again. No change.
* Have finally tried with a new project and defining a similar size map… and the problem is still there.
* I have tried to uninstall and reinstall. Everything seems the same (even the plugins are still there).
* I have tried to export it in a Windows QGIS (both in a Windows partition and in a Windows virtual machine). The first try with Windows worked OK, but now I face the same problem as in Ubuntu.

A couple of ideas:
* could it be a problem of the connection with the WMS server? However, WMS rendering works properly.
* could it be QGIS runs our of memory? If I leave the system monitor open I realize that QGIS would only use 2 of my 8 cores, and not simultaneously, and the core that is in use arrives at 100% of usage. Similarly, used memory never goes beyond 2Gb, but I have 16Gb (and 3Gb in the graphic card).

Hope someone can give me a hint… as I have all my project in QGIS and now cannot get my final result.

Edit
I also tried with limiting tile size, but the problem persisted (with smaller blank tiles, though).
Then I tried doubling the timeout and max-retries parameters, as suggested by . It did work perfectly… at least at that time… One month later I faced the same problem again. This time with a small map (DinA4 size, the previous one was an A0). I have set timeout to 50000 ms and max retries to 20!! No changes.
Two additional details might help figure out where the problem comes from:
* The blank tiles are always the same. Not from a month ago to now, but everytime I face the issue the blank tiles would remain fix during all the trials I do to overcome the problem. That doesn't point to a problem with the internet conection, does it?
* The export image is created in a few seconds, not more than 30, which also suggests timeout parameter is not involved (or not working).

Edit
I found that when this problem arises it stays there no matter what I do, with always the same tiles missing. However, if I let it for a couple of days, it disappears. I mean, once it happens it will happen again in all trials during a couple of days; but if I forgot about it and try two days later it works perfectly again. Seems as if it has some kind or memory… Once the communication has failed for whatever reason it will remember it for a couple of days…


Other than tile size, as noted by @Irssvt, you can also set some timeout and tile retry parameters.

Default timeout per connection is inSettings->Options->network->Timeoutfor network requests

Retry in case of timeout is inSettings->Options->network->Max retryin case of tile request errors.

I coded the last retry parameters in QGIS, funded by Regione Toscana, exactly to solve problems like that you exposed.


Sometime that could occurs with slow connection. You could try to set a tile size for your WMS layer. Change Tile size (e.g 256x256) in WMS Connecition dialog and you see if it works for you:

Sometime it helped me for large compositions. Hope this helps.


I was able to get around this by increasing the cache size underSettings > Options > Network > Cache Settings > Size.

It appears to default to 0, and uses about 4KB per export. When I increased the cache size to 100MB, it used 14MB to store the WMS tiles.

All tiles now appear consistently in the exports.


Could also be RAM available to QGIS… look in Settings for Network and Cache, increase to as much as you like. There is also Cache in Settings for Print Composer.

Would suggest that QGIS look at how they allocate the Cache and see Adobe Photoshop examples of Purge etc, which are really useful.


In Tableau Desktop, select Map > Background Maps > WMS Servers .

In the Add WMS Servers dialog box, type the URL for the server you want to connect to in Tableau, and then click OK .

You can add as many map servers as you want to a workbook. Each WMS server you add appears as a background map in the Background Maps menu.

Save a WMS server as a Tableau map source

After you add a WMS server to your workbook, it is saved with the workbook and available to anyone you share the workbook with. You can also save a WMS server as a Tableau Map Source (.tms) file, which you can share with others so they can quickly connect to it and use it in their own workbooks.

For more information about how to save a map as a Tableau map source, see Save a Map Source (Link opens in a new window) .


Contents


Google Earth displays satellite images of varying resolution of the Earth's surface, allowing users to visually see things like cities and houses looking perpendicularly down or at an oblique angle, with perspective (see also bird's eye view). The degree of resolution available is based somewhat on the points of interest and popularity, but most land (except for some islands) is covered in at least 15 meters of resolution. [6] Melbourne, Victoria Las Vegas, Nevada and Cambridge, Cambridgeshire include examples of the highest resolution, at 15 cm (6 inches). Google Earth allows users to search for addresses for some countries, enter coordinates, or simply use the mouse to browse to a location.

For large parts of the surface of the Earth only 2D images are available, from almost vertical photography. Viewing this from an oblique angle, there is perspective in the sense that objects which are horizontally far away are seen smaller, but of course it is like viewing a large photograph, not quite like a 3D view.

For other parts of the surface of the Earth 3D images of terrain and buildings are available. Google Earth uses digital elevation model (DEM) data collected by NASA's Shuttle Radar Topography Mission (SRTM). [citation needed] This means one can view the Grand Canyon or Mount Everest in three dimensions, instead of 2D like other areas. Since November 2006, the 3D views of many mountains, including Mount Everest, have been improved by the use of supplementary DEM data to fill the gaps in SRTM coverage. [7]

Many people use the applications to add their own data, making them available through various sources, such as the Bulletin Board Systems (BBS) or blogs mentioned in the link section below. Google Earth is able to show all kinds of images overlaid on the surface of the earth and is also a Web Map Service client. Google Earth supports managing three-dimensional Geospatial data through Keyhole Markup Language (KML).

Google Earth has the capability to show 3D buildings and structures (such as bridges), which consist of users' submissions using SketchUp, a 3D modeling program. In prior versions of Google Earth (before Version 4), 3D buildings were limited to a few cities, and had poorer rendering with no textures. Many buildings and structures from around the world now have detailed 3D structures including (but not limited to) those in the United States, Canada, Ireland, India, Japan, United Kingdom, [8] Germany, Pakistan and the cities, Amsterdam and Alexandria. [9] In August 2007, Hamburg became the first city entirely shown in 3D, including textures such as façades. The Irish town of Westport was added to Google Earth in 3D on January 16, 2008. The 'Westport3D' model was created by 3D imaging firm AM3TD using long-distance laser scanning technology and digital photography and is the first such model of an Irish town to be created. As it was developed initially to aid Local Government in carrying out their town planning functions it includes the highest resolution photo-realistic textures to be found anywhere in Google Earth. Three-dimensional renderings are available for certain buildings and structures around the world via Google's 3D Warehouse [10] and other websites.

Recently, Google added a feature that allows users to monitor traffic speeds at loops located every 200 yards in real-time. In version 4.3 released on April 15, 2008, Google Street View was fully integrated into the program allowing the program to provide an on the street level view in many locations.

On January 17, 2009, the entirety of Google Earth's ocean floor imagery was updated to new images by SIO, NOAA, US Navy, NGA, and GEBCO. The new images have caused smaller islands, such as some atolls in the Maldives, to be rendered invisible despite their shores being completely outlined. [11]

Languages

Since version 5.0 Google Earth is available in 38 languages (four of which in two variants):

  • Arabic
  • Bulgarian
  • Catalan
  • Chinese (Traditional)
  • Chinese (Simplified)
  • Croatian
  • Czech
  • Danish
  • Dutch
  • English (American)
  • English (Britain)
  • Filipino
  • Finnish
  • French
  • German
  • Greek
  • Hebrew
  • Hindi
  • Hungarian
  • Indonesian
  • Italian
  • Japanese
  • Korean
  • Latvian
  • Lithuanian
  • Norwegian
  • Polish
  • Portuguese (Portugal)
  • Portuguese (Brazil)
  • Romanian
  • Russian
  • Serbian
  • Slovak
  • Slovenian
  • Spanish (Spain)
  • Spanish (Latin America)
  • Swedish
  • Thai
  • Turkish
  • Ukranian
  • Vietnamese

QGIS » QGIS Application

10. Giovanni Manghi 05:31 Bug report #15899 (Feedback): Crash with segmentation fault in 2.18 - may relate to large PostGIS. Not really sure what to do with this ticket. Replicating the issue locally does not seems possible: I have loaded

10. Giovanni Manghi 05:31 Bug report #15899 (Feedback): Crash with segmentation fault in 2.18 - may relate to large PostGIS. Not really sure what to do with this ticket. Replicating the issue locally does not seems possible: I have loaded

10. Giovanni Manghi 05:31 Bug report #15899 (Feedback): Crash with segmentation fault in 2.18 - may relate to large PostGIS. Not really sure what to do with this ticket. Replicating the issue locally does not seems possible: I have loaded

10. Giovanni Manghi 05:05 Bug report #16136 (Feedback): Field Properties Edit widget settings are not stored I cannot confirm the problem or am I trying the wrong way.
Please test 2.18.4 and/or add the specific steps to repli. Giovanni Manghi 05:05 Bug report #16136 (Feedback): Field Properties Edit widget settings are not stored I cannot confirm the problem or am I trying the wrong way.
Please test 2.18.4 and/or add the specific steps to repli. Giovanni Manghi 05:05 Bug report #16136 (Feedback): Field Properties Edit widget settings are not stored I cannot confirm the problem or am I trying the wrong way.
Please test 2.18.4 and/or add the specific steps to repli. Giovanni Manghi 04:44 Bug report #16246 (Closed): MapTips do not support Unicode names Steps to reproduce:
1. Load a vector layer that uses unicode characters in one of their fields (e. g. "Würselen")
2. Georg Wicke 04:37 Bug report #10900: python filter expression don't work on "value relation" Unless I'm doing something wrong it seems to me that 2.18.4 is still affected. Giovanni Manghi 04:37 Bug report #10900: python filter expression don't work on "value relation" Unless I'm doing something wrong it seems to me that 2.18.4 is still affected. Giovanni Manghi 04:37 Bug report #10900: python filter expression don't work on "value relation" Unless I'm doing something wrong it seems to me that 2.18.4 is still affected. Giovanni Manghi 04:24 Bug report #15803: 2.18: Move Selection to Top not working in attribute table see also #15370 Giovanni Manghi 04:24 Bug report #15370 (Closed): "move selection to top" does not work duplicate of #15803 Giovanni Manghi 04:24 Bug report #15370 (Closed): "move selection to top" does not work duplicate of #15803 Giovanni Manghi 04:22 Bug report #15369 (Closed): layer rendering very slow and QGIS crashes with large number of rule . Chris Freyberg wrote:
> Updates made by other people to this ticket appear to suggest that the reported issue was *sl. Giovanni Manghi 04:22 Bug report #15369 (Closed): layer rendering very slow and QGIS crashes with large number of rule . Chris Freyberg wrote:
> Updates made by other people to this ticket appear to suggest that the reported issue was *sl. Giovanni Manghi 03:57 Bug report #14448 (Feedback): Offset curve tools duplicate lines Regis Haubourg wrote:
> Yes confirmed here. When looking at the logs on postgis side, the offset tool sends the wrong. Giovanni Manghi 03:57 Bug report #14448 (Feedback): Offset curve tools duplicate lines Regis Haubourg wrote:
> Yes confirmed here. When looking at the logs on postgis side, the offset tool sends the wrong. Giovanni Manghi 02:24 Feature request #16245 (Open): DB Manager: Dock the window It would be useful to be able dock DB Manager's window below Processing's or Layer's Panel. Particularly when the use. Filipe Dias 02:06 Редакция b681b7bf (qgis): Flip QgsMapCanvas connects to new style Also remove unneeded duplicate signal Nyall Dawson


2 Answers 2

We were solving similar problem. The best and fastest way for us is:


  1. Rasterize line layer (Raster/Conversion/Rasterize. )
  2. Convert to Proximity (Raster/Analysis/Proximity. )
  3. Use plugin Point sampling tool to get values for all your point from raster

Some of the answers to
Measuring the distance between lines and points in QGIS recommends the NNJoin QGIS plugin (http://arken.nmbu.no/

havatv/gis/qgisplugins/NNJoin/). It will do a nearest neighbour spatial join and include the distance in the result. The NNJoin plugin uses a spatial index, so it should handle reasonably large datasets.


Supported Formats

The geospatial PDF is considered an Adobe Acrobat Portable Document Format (following the PDF 1.7 specification) that contains information that is required to georeference location data. It is an open specification developed and maintained by Adobe Systems. See detailed specifications in Section 8.3 at http://www.adobe.com/devnet/acrobat/pdfs/PDF32000_2008.pdf.

AutoCAD Drawing (dwg) and Drawing Exchange (dxf)

These file types are most commonly created by Autodesk AutoCAD product, though other computer-aided design (CAD) programs such as Bentley MicroStation capable of creating them. Two formats are used by AutoCAD: DXF (drawing exchange format) files and ASCII representations of the binary DWG (drawing) files. Logically, both files are identical and MAPublisher treats both file types in the same manner. AutoCAD files consist of drawing settings and configurations, as well as a series of entities, or graphic elements, organized into layers. MAPublisher provides broad support for many AutoCAD entity types and options. Prior to import, set the colour mode of the Adobe Illustrator document to the same scheme used in the colour table of the CAD file (RGB or CMYK) to ensure colours are imported correctly. Note the hierarchy of layers in multi-feature imports is by feature type: text layers, then point, then line, then area layers. Annotation objects are converted to a point containing attribute information including the text value to be labeled and its angle. Certain symbols may import as "exploded" objects in MAPublisher.

Delimited XY Text Data (csv, tsv, txt)

MAPublisher also supports the import of Delimited Text Data held in a variety of tabular file formats, as long as the data contains coordinate values. File types supported are Text (txt), Tab Separated (tsv) and Comma Separated (csv) files. Import Settings dialog box: In order to import point data with MAPublisher the parameters must be set by clicking the Settings’ button. This operation is required to choose the columns of the selected attribute file that will be used to derive the X and Y coordinates of the data, and ensure correct georeferencing. These and further settings are discussed in the Delimited Text Data Settings section.

Digital Line Graph (opt, dlg)

The USGS (United States Geological Survey) DLG file structure is designed to accommodate categories of spatial data represented on a conventional line map. Node (point), line, and area data types are accepted. The attribute coding scheme is designed to accommodate basic cartographic data categories such as hypsography, hydrography, or political and cultural features, as well as additional thematic data categories.

Esri ArcInfo Generate (gen)

ArcInfo Generate files are created by Esri ArcInfo product, and have a simple ASCII from x-y to x-y format. Due to its simplicity you can also use a text editor such as Notepad to create text files and save them with a GEN extension, which can then be imported with MAPublisher.

Esri Interchange File (e00)

Esri Interchange File files are created by Esri ArcInfo product. A single E00 file describes a complete ArcInfo coverage. The file itself is actually an archive of several smaller files, or sub files, which will have fixed names and follow a predefined data format. MAPublisher will reproduce these sub files as distinct Adobe Illustrator layers on import. Therefore importing a single e00 import can result in the generation of point, area, line and text layers.

Note the hierarchy of layers in multi-feature imports is by feature type: text layers, then point, then line, then area layers.

Shapefiles are most commonly created by Esri ArcGIS or ArcView. Shapefiles store both geometry and attributes for features, and a single shapefile will consist of at least three physical files: the SHP portion contains the geometric data, the DBF contains attributes for the geometric data, and the SHX contains the index information. There is often a PRJ file, which stores coordinate system information and is automatically read by MAPublisher on import. If a shapefile folder does not contain a PRJ file, a coordinate system should be specified in MAPublisher. The important things to remember when importing shapefiles are that the SHP file must be the one that is selected through the MAPublisher import filter and that all its component files must be in the same folder. You may also find that a shapefile directory includes two extra files, a SBN and a SBX, which hold the spatial index for the geometric data. These two files will not exist unless the shapefile was created with an Esri product, and are not necessary for successful import with MAPublisher.

ArcMap Documents (MXD files) contain information describing the map, page layout, layers associated with it, and any objects inserted into the map. ArcMap documents can be imported using MAPublisher Import and Multiple Data Import. Due to certain limitations, only the coordinate system, layer order and map data are retained when importing an ArcMap Document. Any styles, such as strokes, fills and patterns are not preserved. In addition, to import ArcMap documents, at least ArcGIS 9.x must be installed.

FFS stands for FME Feature Store. This format is a memory dump of FME features so it supports the complete FME data model and can hold anything that FME features carry. This makes the format attractive as a holding spot for data that should persist between FME runs.

MAPublisher-FME Auto is a plugin for MAPublisher. It is already installed with MAPublisher and requires activation through MAPublisher Licensing. See MAPublisher FME Auto and FME FFS Import for more information.

Geography Markup Language (gml, xml)

The Geography Markup Language (GML) was designed as a geographic interface language for the Geo-Web. It is currently in draft as an ISO standard (ISO 19136). The goal of the format is to provide users with a set of abstract base objects that can be built into working real world dataset. It uses an XML base to store geometry and feature information that can easily be transported across the Internet.

The GML Simple Feature Profile was created by the Open Geospatial Consortium (OGC) as a restricted but useful subset of the GML specification. It provides a reduced geometry and metadata profile that can be shared across many GIS tasks. This simple feature model can be used as a base to generate local application profiles for a specific work area. Since the GML models base abstract classes, these application profiles (schemas) are required for accessing and processing any GML datasets. GML data has a GML extension, and requires a attributes schema file XSD. Some GML files may have their XSD file referenced to a URL path, we recommend to copy the XSD files locally, to avoid error messages upon import when no internet connection is available. Users have two options to store their GML and XSD files: they can be both located in a same directory or the XSD files can be kept in the MAPublisher GML Schema directory found here:

Windows: C:Program FilesAvenzaMAPublisher 9Data Source FilesGMLSchema

Mac: /Applications/Avenza/MAPublisher 9.7/MAPublisher Plug-In/Data Source Files/GMLSchema

The second option is the most practical if all the GML files are using a same schema (only one instance of the XSD file needs to be saved). Installed with MAPublisher are three default XSD files:

• xml.xsd, generic GML attribute schema.

• nen3610.xsd and top10nl.xsd, models standardized in the Netherlands (maintained by the Dutch topographic office Kadaster).

GML files with a missing XSD file or with an invalid attribute schema will cause a GML validation error upon import (see Format Import Settings). Users have the option to find the appropriate XSD file and copy it to the GML Schema directory or to the GML file directory. This option will assign a type string to all attributes. See Importing Map Data for more details on these settings.

MAPublisher supports the import of simple features (points, lines, polygons, donuts, and aggregates) in GML 2.0 and later versions. MAPublisher supports export to GML 3.1.1.

A GeoPackage is a platform-independent SQLite database file that contains GeoPackage data and metadata tables, with specified definitions, integrity assertions, format limitations and content constraints. While a GeoPackage can contain vector feature data, MAPublisher currently only supports tile matrix pyramid tile images.

Keyhole Markup Language (KML), is an XML-based language for managing the display of three-dimensional geospatial data in the programs Google Earth, Google Maps, Google Mobile and WorldWind. The KML file specifies a set of features for display. Each feature always has a longitude and a latitude and can have other data, such as tilt, heading, and altitude. KML shares some of the same structural grammar as GML. KML files are very often distributed as KMZ files, which are zipped KML files with a KMZ extension. MAPublisher imports and exports both file type based on the KML version 2.2 specifications. KML track and linestring import is supported. KML image import to attributes is supported. When importing and exporting data that includes images, the KMZ format should be used.

Picklist attributes exported from the Avenza PDF Maps app as KML are currently not supported in MAPublisher. Importing just a schema (without data) from Avenza PDF Maps into MAPublisher is not supported.

GPS Exchange Format (GPX for short) is a light-weight XML-based data format designed for the interchange of GPS data. MAPublisher supports GPX schema version 1.1.

Image (png, jpeg, jpg, jpe, tif, tiff, gif, jp2, jpf, jpx, j2k, j2c, jpc, psd, pdd, bmp)

Referenced raster files of the above mentioned formats can be imported and placed directly into a MAPublisher MAP View using Import and Multiple Data Import. These images have the option to be linked or embedded into Adobe Illustrator upon import. Images cannot be reprojected by MAPublisher in Adobe Illustrator. Use Geographic Imager or another third-party software to properly reproject geospatial images.

International Hydrographic Office S-57 (000, 030)

S-57 is referring to the IHO (International Hydrographic Office) Special Publication number 57 related to the IHO transfer standard for Digital Hydrographic Data . Maintained by the IHO, S-57 format is intended for the exchange of digital hydrographic data between national hydrographic offices and for its distribution to manufacturers, mariners and other data users. It is used for the supply of ENC cells (Electronic Navigational Charts) to ECDIS (Electronic Chart Display and Information System). The objects spatial geometry can be of Point, Line or Area geometry, while object descriptions are categorized in object classes, organized in specific attributes schemas. To make full use of this format, refer to the online object catalog available on www.s-57.com.

MAPublisher imports non-encrypted S-57 data into MAP layers named per S-57 object acronym, of type Area, Line or Points. All S-57 Attributes are converted into MAP Attributes.

An Adobe Illustrator template is supplied to automatically style the map after import. The template contains a series of MAPublisher stylesheets linking S-57 imported features to nautical symbols and graphic styles (libraries provided by Avenza). This representation is non-exhaustive and meant to assist users with limited knowledge of the S-57 format to interpret the data contents more easily. The S-57 template and the symbols and graphic styles libraries can be found in the MAPublisher Helpful Styles & Symbols folder (see Appendix 4).

MapInfo Interchange Format (mif)

Files of this type are most commonly created by the MapInfo product, though other products, including MAPublisher, are also capable of generating files in this format. These files exist in pairs where each file has the same name but ends in either a MIF or MID file extension. The MIF portion contains the vector geometric data, and the MID contains the associated attributes. Both files are required in order to successfully import a file of this format to Adobe Illustrator using MAPublisher. The important things to remember when importing MapInfo files are that the MIF file must be the one that is selected through the MAPublisher import filter and that both files must be in the same folder. MAPublisher will automatically locate and deal with the MID file.

The TAB format is a simple, non-topological format for storing the geometric location and attribute information of geographic features, and is an integral part of the MapInfo product. The TAB format defines the geometry and attributes of geographically-referenced features in several files with specific file extensions that are stored in the same folder on disk:

• .tab: main file, table structure in ASCII format.

• .map: the file that stores the feature geometry.

• .id: the file that stores the index of the feature geometry.

• .dat: the dBASE file that stores the attribute information of features.

• .ind: table field indexes (if necessary)

The geometry of each feature is stored as a shape that comprises a set of vector coordinates. The attributes for each feature are stored as a record in a dBASE table (dat) associated with the shapefile (map). There is one record in the dBASE table for each feature in the map file. Raster TAB files cannot be imported in MAPublisher.

To ensure successful import, select the TAB component in the MAPublisher importers.

Import geographic point data from an Excel spreadsheet (version 2007 and earlier only XLSX is not supported) that contains latitude and longitude entries for each row. In order to import point data, click the Settings button in the Import dialog box to choose which columns will be used to as the X and Y coordinates of the data, and ensure correct georeferencing.

MicroStation Design files (dgn) are the native files created by Bentley Systems Inc. (and formerly Intergraph) MicroStation product. Design Files consist of a header, followed by a series of elements. The header contains global information including the transformation equation from design units to user coordinates, as well as the dimension of the elements in the file. Each element contains standard display information, such as its colour, level, class, and style, as well as a number of attributes specific to its element type. During the import process, MAPublisher will produce one layer for each Level that exists in the MicroStation Design File. Annotation objects are converted to a point containing attribute information including the text value to be labeled and its angle.

MAPublisher supports the import of MicroStation J (version 7 and 8) files, however attached raster file will not be imported (ignored). Prior to import, the colour mode of the Adobe Illustrator document should be the same scheme used in the colour table of the original file to ensure that the colours are interpreted correctly.

The hierarchy of layers in multi-feature imports is by feature type in the following order: text layers, then point layers, then line layers, then area layers. Raster files attached to DGN files are ignored during the import process.

Files are exported from MAPublisher as MicroStation J files. Upon export, users may select a DGN seed file. All information in the seed file gets carried over to the output file, such as level (layer) definitions, units, colors, line styles definitions, etc. If an exported layer name matches a level name in the seed file, the data of that layer is appended to the existing level, if not, a new level is created.

Spatial Data Transfer Standard (SDTS) (catd.ddf)

Digital cartographic products of the USGS are available in the Spatial Data Transfer Standard format, and are generally distributed over the Internet as a means of promoting the standard. For SDTS import, select the catd file (xxxxcatd.ddf), which is the index file that contains a description of the other files in the SDTS transfer. Individual DDF files cannot be imported. Generally all SDTS downloads will contain the CATD file.

TIGER is an abbreviation of Topologically Integrated Geographic Encoding and Reference System, and was developed by the U.S. Census Bureau. TIGER/Line files are a digital database of geographic features, such as roads, railroads, rivers, lakes, political boundaries, census statistical boundaries, etc., that cover the entire United States. The database contains information about these features such as their location in latitude and longitude, the name, the type of feature, address ranges for most streets, the geographic relationship to other features, and other related information. TIGER/Line files are the public product created from the Census Bureau TIGER database of geographic formation. TIGER was developed in order to support the mapping and related geographic activities required by the census and sample survey programs. More information on the TIGER/Line file format and data product can be found on the US Census web page at: http://www.census.gov/geo/www/tiger/

MAPublisher considers the RT1 or BW1 file as the TIGER dataset. Even though each county will consist of a series of files with a common base name, there may be a number of different extensions. Remember to select the RT1 or BW1 file when importing TIGER data.

Web Feature Service is an interface standard designed by the Open Geospatial Consortium (OGC) for GIS vector data transactions across the Web. The MAPublisher WFS import connects to servers that use versions 1.0.0 and 1.1.0 of the OGC standard. WFS servers provide GML files, which are read using the MAPublisher GML importer. The GML importer supports the GML simple features 2.0+ profile.

As the WFS importer is read-only, WFS-T is not supported. See Importing WFS for more information on WFS parameters.

Web Map Service is an interface standard designed by the Open Geospatial Consortium (OGC) for GIS raster data transactions through http protocol. The MAPublisher WMS import connects to servers that use version 1.1.1 of the OGC standard. WMS data formats include PNG, JPG, TIF and GeoTIFF. See Importing Map Data for information on WMS parameters.

ArcSDE geodatabases are multi-user Esri spatial databases, that allow users to store, use, and manage their GIS data in one of the following commercial database management systems (DBMS): IBM DB2, IBM Informix, Microsoft SQL Server, or Oracle. They are available in three levels of flexibility: desktop, workgroup and enterprise. The Basic Esri ArcSDE Server import option allows users who have a free Esri desktop application called ArcReader to import feature classes from ArcSDE geodatabases, but with some limitations on the selection functions — see Spatial Databases for more information.

† Basic Esri ArcSDE Servers are not supported on Mac due to limitations of the related Esri libraries.

ArcSDE geodatabases are multi-user Esri spatial databases, that allow users to store, use, and manage their GIS data in one of the following commercial database management systems (DBMS): IBM DB2, IBM Informix, Microsoft SQL Server, or Oracle. They are available in three levels of flexibility: desktop, workgroup and enterprise. The Esri ArcSDE geodatabase import option allows users who have ArcGIS software and a valid license to import all ArcSDE geodatabase types with advanced options for the selection — see Spatial Databases for more information.

† Esri ArcSDE geodatabases are not supported on Mac due to limitations of the related Esri libraries.

Esri File Geodatabase † (gdb)

A File geodatabase is a native Esri single-user spatial database. It is a collection of various types of GIS datasets held in a file system folder. This is the recommended native data format for ArcGIS. Importing this format requires ArcGIS software and a valid license — see Spatial Databases for more information.

† Esri File geodatabases are not supported on Mac due to limitations of the related Esri libraries.

Esri Personal Geodatabase † (mdb)

A Personal geodatabase is a native Esri single-user spatial database. This is the original data format for ArcGIS geodatabases stored and managed in Microsoft Access data files. Importing this format requires ArcGIS software and a valid license — see Spatial Databases for more information.

† Esri Personal geodatabases are not supported on Mac due to limitations of the related Esri libraries.

MAPublisher also supports Adobe Illustrator (ai) files created by Cartographica, a third-party GIS software.Cartographica users who wish to use files in MAPublisher must check the Include data in export option during export.

MAPublisher reads Adobe Illustrator files exported by Cartographica and extracts the geospatial information to convert it into layers and MAP Views—including projection, map scale and page position. However, there may be limitations when working with these files and it is recommended that they be saved as the latest version of Adobe Illustrator files compatible with your system (this is required before exporting to geospatial PDF).


TopoJSON Map Files for Power BI Shape Map

About a month ago, I started a collection of TopoJSON map files in response to a request on the Power BI Community forum. TopoJSON is D3’s preferred format, which is why Power BI users have suddenly found themselves learning more about it after the Shape Map was released. It is an optimized and lightweight cousin of the more prevalent GeoJSON, but there are not many files available in TopoJSON format. As a result, a subset of Power BI users have been converting files from Shapefile, GeoJSON, and other formats into TopoJSON on their own.

I have posted a modest collection of files in a GitHub repository at:
https://github.com/deldersveld/topojson

Please make sure that you save the “Raw” version of the .json file. Rather than right-clicking and performing a Save Link As on the links directly in the Read Me, click the link to view a preview of the map, and then right-click on the Raw button at the top and select Save Link As.

Here’s a sample of what is available:

  • World map with continents and world map with countries
  • Individual continent maps with countries
  • US counties
  • US congressional districts (2015)
  • US cartogram based on each state’s population
  • Individual US state-level counties
  • Denmark – counties and municipalities
  • Finland – provinces and regions
  • France – departments
  • Germany – regions
  • India – states and districts
  • Japan – prefectures and towns
  • Netherlands – municipalities
  • Norway – counties and municipalities
  • Spain – comunidades autonomas and provincias

The US cartogram is the only one at this time that was not simply a conversion from another source. It was a test of R’s new cartogram package. I took a sample US map from R’s albersusa package and created a map that distorts the states based on their 2014 estimated population. As an aside, if you have some R experience and want to explore alternatives to traditional maps, there is a lot that can be done with R that can then be converted for later use in Power BI.

The most important note is that nearly all of these files personally have been tested for use in Power BI. As a result, users should not encounter some of the distortion issues in Power BI that can sometimes occur when converting a Shapefile or other source into TopoJSON. In many cases, the polygons also have been simplified for performance reasons in Power BI without sacrificing much high-level detail.

Please note that I have only converted from an original source. I will not branch from an original source by making custom modifications to shapes.

Also, check out 10 Ways to Create Maps in Microsoft Power BI to see options other than the Shape Map.


GEOG 585 Syllabus (Summer 2021)

Dr. Panagiotis Giannakis is the lead instructor for the Summer 2021 offering of Geog 585. He is an assistant teaching professor for the John A. Dutton e-Education Institute, College of Earth and Mineral Sciences at Penn State.

Email: Please use the course e-mail system (it ensures your emails don't get caught up in any spam filters, especially if you attach any scripts). I check e-mail regularly and will do my best to respond to questions at least once per weekday and once on weekends unless I notify you otherwise. If Canvas is down you can try [email protected]

Course Overview

Geography 585: Open Web Mapping is a 10-week online course that gives you experience with sharing geographic information on the Internet using free and open source software (FOSS) and open specifications. It is an elective course in Penn State's online geospatial education programs, including the Master of Geographic Information Systems.

The two main purposes of Geog 585 are to help you understand the importance of web services and to give you some experience making web maps with FOSS and open standards. You could certainly implement web services using proprietary software, too however, the cost of a proprietary GIS server package makes FOSS an attractive area of study for basic web mapping tasks.

The purpose of Geog 585 is not to promote FOSS over proprietary software, or vice versa (you could find plenty of materials on the Internet debating this subject) however, Geog 585 should familiarize you with the capabilities and shortfalls of the current FOSS landscape to the point that you can make an informed decision about how to use FOSS in your own web mapping tasks.

The set of FOSS and open data sources you will be exposed to in Geog 585 includes QGIS, GDAL, GeoServer, GeoWebCache, TileMill, OpenStreetMap, and Leaflet. You will also learn about open data standards such as GeoJSON, KML, and OGC web service specifications.

Prerequisites

This course requires you to do some programming with JavaScript and the Leaflet API. You don’t have to know anything about Leaflet yet, but it is required that you have:

  • enough formal experience with writing computer programs or scripts that you are comfortable identifying and using fundamental constructs such as variables, loops, decision structures, error handling, objects, and so forth. A B grade or above in Geog 485 satisfies this prerequisite. Exceptions require equivalent programming experience and instructor approval.
  • Enough experience with JavaScript that you are able to easily identify the above constructs when you see them in a piece of JavaScript code. A B grade or above in Geog 863 satisfies this prerequisite, or you can do your own preparation using the W3Schools JavaScript tutorial.
  • Enough experience with HTML and CSS that you are easily able to view and interpret the basic elements of page markup, such as the head, body, script tags, and so forth. Geog 863 satisfies this prerequisite, or you can do your own preparation using the W3Schools HTML tutorial.

Required Course Materials

There is no required textbook for this course. You will be required to complete various online readings.

If you will not have a consistently available Internet connection available during this course, please contact the instructor prior to beginning.

Assignments and Grading

Geog 585 has nine lessons. Each of them is one week in length. The tenth week of the course is reserved for you to work on your term project (described further below). On most weeks, you will see:

  • conceptual lesson materials
  • a walkthrough that takes you through a new piece of software or functionality step by step
  • an assignment that typically expects you to apply what you learned in the walkthrough. Be aware that some assignments have multiple parts, and some weeks’ assignments are worth more than others’.

The walkthroughs and assignments in Geog 585 require a significant time commitment to complete and often involve installing or using new software. Please start working on the lesson at the beginning of the week to allow for completing a high-quality deliverable on time and any troubleshooting that might be necessary along the way.

Quizzes

Quizzes are administered throughout the course to test your knowledge of the material and your ability to think and reason independently about the concepts presented.

Term project

During the course, you will work on a term project that synthesizes the skills that you gain throughout the lessons. Many of the weekly assignments are directly related to building your term project in other words, you can use your term project data in the weekly assignments, and some pieces of your weekly assignment deliverables may appear in your term project deliverables. The final week of the course is set aside for full-time work on your term project.

Grading

Deliverables are weighted in the following fashion to obtain your grade:

Make-up Exam Policy

Because this course has no exams, there is no Make-up Exam Policy.

Letter grades will be based on the following percentages:

Letter grades and percentages
A 90-100%
A- 87.5-89.9%
B+ 85-87.4%
B 80-84.9%
B- 77.5-79.9%
C+ 75-77.4%
C 70-74.9%
D 60-69.9%
F <60%
X Unsatisfactory (student did not participate)

Percentages refer to the proportion of all possible points earned by the student after the above weights have been applied.

Late Work

Any assignment not submitted by the due date on the course calendar in Canvas shall incur a 10% deduction in grade prior to any other deduction made by the instructor when grading the assignment. An additional 10% will be deducted for each additional week late. The instructor may choose to modify or waive these penalties under exceptional circumstances (such as severe health issues).

GEOG 585 Course Schedule

Weekly assignments (for weeks 1-9) and quizzes (in weeks 3, 6, and 9) are always due at the end of each week by Wednesd ay, 11:59 pm (Eastern Time). In addition, a brief term project proposal document needs to be submitted at the end of week 2. In week 10, a video demonstrating your term project needs to be submitted by the end of Sunday the remaining term project deliverables (report and reviews of two other students' video) are due by the end of Wednesday (last day of class).

  • Comprehend the structure of GEOG 585.
  • Know how to use the course management system.
  • Read the course syllabus.
  • Complete the W3CSchools JavaScript and HTML tutorials (if needed).
  • Describe the roles of clients, servers, and requests and how they contribute to web service communication patterns.
  • Identify benefits and challenges to FOSS and how they should be weighed when choosing a software platform.
  • List common FOSS solutions for general computing and GIS and discuss how you have seen these used in the “real world.”
  • Recognize when and how FOSS might be used in a “hybrid” model with elements of proprietary software.
  • Add and symbolize GIS data in QGIS.
  • Walkthrough: Installing and exploring QGIS.
  • Responding to FOSS.
  • Identify the pieces of hardware and software architecture used in web mapping and describe the role played by each.
  • Recognize the roles of basemaps and thematic layers in a web map, and identify examples of each.
  • Critique the layer construction and architecture of a web map.
  • Log into the GeoServer administrator page and preview layers.
  • Walkthrough: Setting up GeoServer.
  • Analyze two web maps.
  • Term project proposal.
  • List common open file and database formats for spatial data and give appropriate uses for each.
  • Recognize the advantages of various data storage architectures and formats.
  • Process (clip and project) GIS data using QGIS and GDAL, and describe when it would be appropriate to use each.
  • Experiment with a new GDAL function and use the documentation to learn how to invoke it.
  • Walkthrough: Clipping and projecting vector data with QGIS and OGR.
  • Walkthrough: Processing raster data with QGIS and GDAL.
  • Prepare term project data and experiment with GDAL utility.
  • Quiz 1.
  • Identify the pros and cons to using a dynamically drawn web map service (as opposed to a tiled service).
  • Recognize the role of OGC in defining open geospatial web service specifications.
  • Learn about the main geospatial web service standards (OGC's W*S specifications, REST).
  • List the basic functions of a WMS and describe how and why each would be invoked.
  • Expose GIS datasets as a WMS using GeoServer.
  • Use SLDs to define layer styling in a WMS. Create the SLDs using code and using the GUI environment of QGIS.
  • Identify and critique a WMS used on a public-facing website.
  • Walkthrough: Serving and styling a WMS with GeoServer.
  • Walkthrough: Advanced styling and group layers with WMS.
  • Review a WMS and serve some of your term project data as a WMS.
  • Describe the advantages of tiled web maps and identify when it is appropriate to use them.
  • Recognize strategies and techniques for creating and updating large tiled web maps.
  • Create tiles for a WMS using GeoWebCache.
  • Use best practices in multiscale map design to create a tiled basemap using TileMill.
  • Discuss hosting options for tiled maps. Unpack and upload your tiled map to your own web space (on PASS).
  • Walkthrough: Creating tiles with GeoServer using GeoWebCache.
  • Walkthrough: Creating tiles with Mapnik using TileMill.
  • Examine tiled maps, then build your own.
  • Identify commonly-used web mapping APIs (both proprietary and FOSS) for realizing mashups and interactive elements in web maps, and recognize programming patterns that are common to each.
  • Choose developer examples that relate to your web mapping task and adjust the code to meet the needs of your own application.
  • Use Leaflet to create mashups of different kinds of map layers (like a tiled basemap combined with a WMS thematic layer).
  • Create interactive informational popups for your web map features using Leaflet.
  • Walkthrough: Overlaying a WMS on a tiled map with Leaflet.
  • Overlay your own data in Leaflet and examine real world use of a web mapping API.
  • Quiz 2.
  • Describe benefits and challenges of drawing thematic vector map layers in the web browser.
  • Choose between KML, GeoJSON, and other formats for drawing vector data in the browser.
  • Understand how vector layers can be symbolized on the fly to provide a more interactive web map experience.
  • Draw thematic vector layers in a web map using Leaflet and change the symbolization in response to map events.
  • Walkthrough: Adding interactive GeoJSON layers in Leaflet.
  • Make your own mashup with a vector layer drawn in the browser.
  • Implement techniques for data filtering and classification using Leaflet.
  • Describe OGC specifications for vector data editing (WFS) and geoprocessing (WPS) in web maps.
  • Implement the layer switcher and other controls from Leaflet according to application needs.
  • Choose a web presentation framework such as Bootstrap and apply it to your Leaflet applications.
  • Query and display geographic attributes (including links to images and web pages) in your web map application.
  • Learn and critically evaluate a new piece of FOSS GIS.
  • Lesson 8 online materials
  • Steiniger, S., & Hunter, A. J. (2013). The 2012 free and open source GIS software map–A guide to facilitate research, development, and adoption. Computers, Environment and Urban Systems, 39, 136-150.
  • Walkthrough: Making a thematic map with Bootstrap controls and the Leaflet framework.
  • Independent exploration of FOSS.
  • Define “open data” and describe some of the differences in use conditions among open data options.
  • Recognize the benefits and weaknesses of OpenStreetMap and its process of crowdsourcing.
  • Describe options for retrieving data from OpenStreetMap.
  • Edit OpenStreetMap according to community-defined tagging standards, and describe what this experience taught you about open data sources.
  • Walkthrough: Getting source data from OpenStreetMap.
  • Evaluate OpenStreetMap usage and contribute to OpenStreetMap.
  • Quiz 3.
  • Synthesize the material from the previous lessons to create an interactive web map combining data sources of your choosing. Justify your choices of data storage formats, web service types, and API elements used, with respect to both aesthetics and performance.
  • Term project video (Sunday).
  • Term project report and review of project videos of two other students.

Course Policies

Technical Requirements

For this course, we recommend the minimum technical requirements outlined on the World Campus Technical Requirements page, including the requirements listed for same-time, synchronous communications. If you need technical assistance at any point during the course, please contact the HelpDesk (for World Campus students) or the IT Service Desk (for students at all other campus locations).

Internet Connection

Access to a reliable Internet connection is required for this course. A problem with your Internet access may not be used as an excuse for late, missing, or incomplete coursework. If you experience problems with your Internet connection while working on this course, it is your responsibility to find an alternative Internet access point, such as a public library or Wi-Fi ® hotspot.

Mixed Content

This site is considered a secure web site which means that your connection is encrypted. We do however link to content that isn't necessarily encrypted. This is called mixed content. By default, mixed content is blocked in Internet Explorer, Firefox, and Chrome. This may result in a blank page or a message saying that only secure content is displayed. Follow the directions on our Technical Requirements page to view the mixed content.

Equations

Penn State E-mail Accounts

All official communications from Penn State are sent to students' Penn State e-mail accounts. Be sure to check your Penn State account regularly, or forward your Penn State e-mail to your preferred e-mail account, so you don't miss any important information.

Academic Integrity

This course follows Penn State's College of Earth and Mineral Sciences Academic Integrity Guidelines for Undergraduates. Penn State defines academic integrity as "the pursuit of scholarly activity in an open, honest and responsible manner." Academic integrity includes "a commitment not to engage in or tolerate acts of falsification, misrepresentation, or deception." In particular, the University defines plagiarism as "the fabrication of information and citations submitting others' work from professional journals, books, articles, and papers submission of other students' papers, lab results or project reports and representing the work as one's own." Penalties for violations of academic integrity may include course failure. To learn more, see Penn State's Academic Integrity Training.

Course Copyright

All course materials students receive or to which students have online access are protected by copyright laws. Students may use course materials and make copies for their own use as needed, but unauthorized distribution and/or uploading of materials without the instructor’s express permission is strictly prohibited. University Policy AD 40, the University Policy Recording of Classroom Activities and Note Taking Services addresses this issue. Students who engage in the unauthorized distribution of copyrighted materials may be held in violation of the University’s Code of Conduct, and/or liable under Federal and State laws.

For example, uploading completed labs, homework, or other assignments to any study site constitutes a violation of this policy.

Accommodations for Students with Disabilities

Penn State welcomes students with disabilities into the University's educational programs. Every Penn State campus has an office for students with disabilities. The Office for Student Disability Resources website provides contact information for Campus Disability Coordinators at every Penn State campus. For further information, please visit the Office for Student Disability Resources website

In order to receive consideration for reasonable accommodations, you must contact the appropriate disability services office at the campus where you are officially enrolled. You will participate in an intake interview and provide documentation. See documentation guidelines at Applying for Services from Student Disability Resources. If the documentation supports your request for reasonable accommodations, your campus’s disability services office will provide you with an accommodation letter. Please share this letter with your instructors and discuss the accommodations with them as early in your courses as possible. You must follow this process for every semester that you request accommodations.

Change in Normal Campus Operations

In case of weather-related delays or other emergency camps disruptions or closures at the University, this online course will proceed as planned. Your instructor will inform you if there are any extenuating circumstances regarding content or activity due dates in the course due to these delays or closures. If you are affected by a weather-related emergency, please contact your instructor at the earliest possible time to make special arrangements.

Reporting Educational Equity Concerns

Penn State takes great pride to foster a diverse and inclusive environment for students, faculty, and staff. Acts of intolerance, discrimination, or harassment due to age, ancestry, color, disability, gender, gender identity, national origin, race, religious belief, sexual orientation, or veteran status are not tolerated (Policy AD29 Statement on Intolerance) and can be reported through Educational Equity via Report Bias.

Counseling and Psychological Services

Many students at Penn State face personal challenges or have psychological needs that may interfere with their academic progress, social development, or emotional wellbeing. The university offers a variety of confidential services to help you through difficult times, including individual and group counseling, crisis intervention, consultations, online chats, and mental health screenings. These services are provided by staff who welcome all students and embrace a philosophy respectful of clients’ cultural and religious backgrounds, and sensitive to differences in race, ability, gender identity, and sexual orientation. Services include the following:

Counseling and Psychological Services at University Park (CAPS): 814-863-0395
Counseling Services at Commonwealth Campuses
Penn State Crisis Line (24 hours/7 days/week): 877-229-6400
Crisis Text Line (24 hours/7 days/week): Text LIONS to 741741

Military Personnel

Veterans and currently serving military personnel and/or spouses with unique circumstances (e.g., upcoming deployments, drill/duty requirements, disabilities, VA appointments, etc.) are welcome and encouraged to communicate these, in advance if possible, to the instructor in the case that special arrangements need to be made.

Connect Online with Caution

Penn State is committed to educational access for all. Our students come from all walks of life and have diverse life experiences. As with any other online community, the lack of physical interaction in an online classroom can create a false sense of anonymity and security. While one can make new friends online, digital relationships can also be misleading. Good judgment and decision making are critical when choosing to disclose personal information to others whom you do not know.

Deferred Grades

If you are prevented from completing this course within the prescribed amount of time for reasons that are beyond your control, it is possible to have the grade deferred with the concurrence of the instructor, following Penn State Deferred Grade Policy 48-40. To seek a deferred grade, you must submit a written request (by e-mail or U.S. post) to the instructor describing the reason(s) for the request. Non-emergency permission for filing a deferred grade must be requested before the beginning of the final examination period. It is up to the instructor to determine whether or not you will be permitted to receive a deferred grade. If permission is granted, you will work with the instructor to establish a communication plan and a clear schedule for completion within policy. If for any reason, the coursework for the deferred grade is not complete by the assigned time, a grade of "F" will be automatically entered on your transcript.

Attendance

This course will be conducted entirely online. There will be no set class meeting times, but you will be required to complete weekly assignments with specific due dates. Many of the assignments are open for multiple days, so it is your responsibility to complete the work early if you plan to travel or participate in national holidays, religious observances or University approved activities.

If you need to request an exception due to a personal or medical emergency, contact the instructor directly as soon as you are able. Such requests will be considered on a case-by-case basis.

Diversity, Inclusion, and Respect

Penn State is “committed to creating an educational environment which is free from intolerance directed toward individuals or groups and strives to create and maintain an environment that fosters respect for others” as stated in Policy AD29 Statement on Intolerance. All members of this class are expected to contribute to a respectful, welcoming, and inclusive environment and to interact with civility.

For additional information, see:

Mandated Reporting Statement

Penn State’s policies require me, as a faculty member, to share information about incidents of sex-based discrimination and harassment (discrimination, harassment, sexual harassment, sexual misconduct, dating violence, domestic violence, stalking, and retaliation) with Penn State’s Title IX coordinator or deputy coordinators, regardless of whether the incidents are stated to me in person or shared by students as part of their coursework. For more information regarding the University's policies and procedures for responding to reports of sexual or gender-based harassment or misconduct, please visit Penn State's Office of Sexual Misconduct Prevention & Response website.

Additionally, I am required to make a report on any reasonable suspicion of child abuse in accordance with the Pennsylvania Child Protective Services Law.

Disclaimer

Please note that the specifics of this Course Syllabus can be changed at any time, and you will be responsible for abiding by any such changes. All changes will be communicated with you via e-mail, course announcement and/or course discussion forum.


Web Map Context Document

The WMC specification applies to the creation and use of documents which unambiguously describe the state, or "Context," of a WMS client application in a manner that is independent of a particular client and might be used by different clients to recreate the same application state. The specification defines an encoding for the Context using XML.

Web Map Context Documents contain all information needed to display a map or a set of maps for a selected area and size. These can come from one or more Web Map Service (WMS) servers and display the map composition within a given area of interest. A Context Document includes information about the server(s) providing layer(s) in the overall map set, the bounding box and map projection shared by all the maps, sufficient operational metadata for client software to reproduce the map set, and ancillary metadata used to annotate or describe the maps and their provenance for the benefit of human viewers. Context Documents can be generated, saved, reused and exchanged within and between mapping applications that implement the same WMC standard.

There are several possible uses for Context Documents:

  • To provide default start-up views for particular classes of user. Such a document would have a long lifetime and public accessibility.
  • To save the state for a Viewer Client as they navigate and modify map layers.
  • To store not only the current settings but also additional information about each map layer (e.g., available styles, formats, SRS, etc.), to avoid having to query the map server again once the user has selected a layer.
  • To save the document from one client session and transfer it to a different client application, to allow start-up with the same Context.

Context Documents can be catalogued and discovered, thus providing a level of granularity broader than individual layers.

Defining Elements

The parent element of the ViewContext document includes as children:

  • A General element that provides layer-independent Context information. It states the bounding box in units of a particular Spatial Reference System (SRS) that represents the geographic extent of the map, and a dimension as a pair of integers that represents the suggested pixel size for the map. This element also contains some metadata about the particular WMS Context, that includes a title, abstract, keywords, and other information.
  • A sequential LayerList gives specific details about each layer in use. It encapsulates all the layers in the current Context. One or more of these layers may be retained in the Context but can be hidden from the display. The LayerList contains a series of one or more Layer elements:
  • Each Layer element is nearly identical to that in Web Map Service (WMS) Capabilities. It contains layer metadata such as a title, an abstract and a legend that may reflect what is advertised by the server issuing the layer. But, it is clear that a very common use of Context is to change the name and the description to allow either internationalization, user refinement, or eventually, a completely user-defined description.
  • Some information concerning the current state of the layer within the WMS Context is also held there. The Layer element contains a binary attribute “hidden” which, if non-zero, instructs the client that, despite the layer being within the Context, it must not be displayed. A client should also provide a means for the user to know that such a layer exists and a means to make that layer visible.
  • The Layer element contains information about the server it is issued from, and some information about the format in which that layer may be asked for by a client. It also may contain several styles that should be presented to the client to allow different presentations of the map, one of these styles being advertised as the currently selected one.
  • The Version attribute specifies the ViewContext specification revision to which this XML Schema applies.

XML Encoding

The XML encoding of a Context Document is given in the OGC® WMC Specification, which defines the required and optional content of the Context Document and how the document is formatted.

Description of a Context Collection

Context Collections represent a list of Context Documents. Context Collections may be used in several ways:

  • A particular Viewer Client could use a Collection to construct a menu of default start-up views.
  • A Collection of related Context Documents could serve as a script for a demonstration.
  • A client could create a Collection to "bookmark" public or user-specific Contexts. The creation of such a Collection might be managed by the Viewer Client itself.

Uses for WMC Documents

Web Map Context Documents are human-readable XML documents which may result from a search of WMS layers. They can be transmitted as static documents.

Typical Scenario: A user produces a custom map view of a geographic area of interest from one or more WMS instances. The user then saves or stores the state of the map in the application as a Web Map Context Document. Another Viewer Client could then access the Web Map Context Document and display the map in the look and feel of the respective application. As a result, a single application-neutral Context Document can be used by an infinite number of Viewer Clients and applications.


2 Answers 2

Part of the "problem" for anyone relatively new to Gimp is that there are often many ways to reach any desired outcome and the desired outcome is always a personal preference. Hopefully you will get many answers with alternative solutions.

Based on your description and attached medal, I presume you have been watching "How to create gold medal with GIMP" tutorial on YouTube by Jose Navas which is an ok tutorial and intro to using bump maps in Gimp. The "Gold Gradient" used in the tutorial is not necessarily the best way to start but since you've already chosen that path, here are some methods and filters you can play with. Try different combinations. Always first make a copy of the layer you wish to modify. Play with Layer Opacity Values and Layer Blend Modes. Since you already know how to use bump maps, an easy way to proceed might be to search and download "Gold Medal Textures", open them as layers and use them as bump maps in the same manner as you did with pressed image.

I would suggest you first install G'MIC Plugin for Gimp. That way you have more filters and options.

Some filters you might wish to try:

  • Cartesian Transform (Filters -> G'Mic -> Deformations -> Cartesian Transform)
  • Gaussian Blur (Filters -> Blur -> Gaussian Blur)
  • Random (Filters -> G'Mic -> Deformations -> Random)
  • Textured Glass (Filters -> G'Mic -> Deformations -> Textured Glass)
  • Noise (Filters -> G'Mic -> Degradations -> Noise [Additive])
  • Cinema (Filters -> G'Mic -> Testing -> Gentlemanbeggar -> 60's cinema)
  • Metallic Grain (Filters -> Gmic -> Testing -> Photocomix -> Metallic Grain)
  • Relief Light (Filters -> G'Mic -> Lights & Shadows -> Relief light)
  • Brushify (Filters -> G'Mic -> Artistic -> Brushify)

In the samples below I've typically used layer opacity values between 20-50 percent so effects are subtle. Hopefully you can see some differencies when zooming in.

If you wish to control lighting options and optionally add realism by using environment maps (much the same way as bump maps), you can try Lighting Effects (Filters -> Light and Shadow -> Lighting Effects. ).

For desired outcome, try different material properties, maps, light colors, intensities, number of lights, lamp types etc.

There seems to be plenty of Photoshop tutorials available so depending on how well you know your way around Gimp you could perhaps attempt to follow one of those tutorials and try to replicate the tasks in Gimp. One good Youtube tutorial is called "How To Create a Realistic Coin In Photoshop". It introduces some basic concepts and methods that are Application independent and achievable also in Gimp or most any other image editor.

Finally, if you wish to learn more about surface texturing and photorealistic material creation, it might be a good idea to search for Blender "Hard Surface Texturing" tutorials even if you are not a Blender user. Many Blender artists create their weathered hard surface texturing brushes, bump maps, scratch brushes etc. in Gimp.


Watch the video: Mosaic Multiple Raster Layers together Using QGIS