Extending GeoPackage to include Project/Styling information

This Blog post introduces some of the work GeoCat is working on to satisfy your mapping needs. You probably remember a situation in which you were looking to a mapping project in say ArcGIS, a webpage or phone and bumped into the fact that a specific tool is not available in that environment. Imagine an export button which would allow you to export that project and open it in your favourite editor to apply the tool you had in mind.

With this use case in mind we’ve looked at our current portfolio to see if we can support it. We defined 2 user stories:

• Export an MXD project from ArcGIS and open it in QGIS
• Export a subset of Metadata from GeoNetwork including linked WFS-data and open it on a mobile phone

After some research we found the work by Pirmin Kalberer at https://github.com/pka/qgpkg is an approach that can facilitate this need. However the work by Pirmin is quite QGIS oriented, we suggested a more OGC aware approach here. The idea is that the project info (layer order/visibility/grouping) is stored as an OWS_Context embedded in a GeoPackage and styling information is stored as Styled Layer Descriptor in the GeoPackage. Also the metadata of the embedded datasets is stored using the GeoPackage metadata extension. GeoPackage is based on SQLite, so has native support on may environments, including phones.

Based on the work by Pirmin, my colleague Joana Simoes has implemented initial support for the ows_geopackage_extension. GeoPackage support has also recently been introduced in GeoCat Bridge, to replace the limited shape format we’ve been using for the last 10 years. In coming months GeoCat Bridge will be extended to support the full export of GeoPackages having the ows_geopackage_extension.

To further promote the ows_geopackage_extension (and other standards) GeoCat has recently joined the Open Geospatial Consortium. We are looking forward to the upcoming TC Meeting in Delft and Testbed-13 in which a Styling Extension of GeoPackage is on the agenda.

We’ve also looked at how we can improve the GeoPackage support inside GeoNetwork. We have identified 3 potential improvements:

• Import a GeoPackage and: visualise it in the map viewer and/or import the containing metadata into the catalogue.
• Export a subset of metadata as a GeoPackage. GeoNetwork currently uses a proprietary format called «metadata exchange format«. This formats is basically a zip file including the metadata, some tags and resources (thumbnails). Would be interesting to replace mef by GeoPackage. The exported GeoPackage can contain also the data as exported from linked WMS/WFS/WCS-es for use offline.
• Export a mapping project as GeoPackage. Similar to above, but exported from the map viewer. The export can now contain mapping information, such as layer order.

We have currently no plan for extending a mobile phone product to support the ows_geopackage_extension. Let us know if you have any ideas? Initially we invite you to open GeoNetwork on your phone and open the GeoPackage in there.