The default encodings for INSPIRE, as per INSPIRE Data Specifications, are usually GML for vector data and GeoTIFF for raster coverages. However, since a single encoding is not optimal for all use cases, alternative encodings can also be used. In our previous blog post about alternate encodings, we already explained how alternative encodings can help to improve the data usability.
The GML default encoding works very well for system-to-system interoperability. But visualizing and analyzing large complex INSPIRE GML files in a GIS can be challenging. Thus, we have been working on supporting Geopackage, an alternative INSPIRE encoding that can be used directly on desktop.
In our view GeoPackage is the optimal, open format for delivering medium to large sized data sets to GIS users. It is a single file that can store tables, vector geometries and rasters. It is extensible and fast to access. It can deal with simple and more detailed data models well. There is even the option to store views and styles. And GeoPackage does not have some of the shortcomings of GML such as 11-character attribute limits, unknown encodings, and missing or incomplete projection files.
Like INSPIRE GML datasets, GeoPackages are interoperable. In addition, GeoPackages can be used across all enterprise and personal computing environments. GeoPackages work much better even in environments with limited connectivity and bandwidth, such as mobile devices. Below you can find a comparison of GeoPackage and GML, and see how they complement each other:
There were always requests to add GeoPackage to the list of supported formats for hale»studio. To this end, we added a GeoPackage Reader and a Writer that was released with hale»studio 4.0. The Writer can create GeoPackages from scratch, including the schema and the metadata. This work was possible thanks to funding from Umweltbundesamt Austria and Rijkswaterstaat Netherlands, and support from the European Environmental Agency.
You can load data such as a shapefile, a FileGeodatabase, or simple GML. Then you map that data to a GeoPackage-specific schema or even an XML schema. Finally, you export your transformed data. If you already have GeoPackage source data, you can load it directly into hale»studio and use it in a transformation project.
The UML to Geopackage (U2G) rule was developed by UNIZAR, and has two parts:
More information about the issues that GeoPackage addresses via encoding rules can be found here.
The GeoPackage encoding takes a two-step approach. The first step occurs at the conceptual level, when INSPIRE constructs are transformed into GeoPackage constructs. These constructs are then turned into a Geopackage template. This template varies according to INSPIRE theme.
The mapping from the UML model to the GeoPackage, as per the original creators, can be found below:
The correspondence tables for other standards (for e.g. ISO 19115, ISO 19139, etc.) can be found here.
Between 2020 and now, wetransform supported the EEA to provide a GeoPackage Encoding for European Noise directive data.
The END consists of multiple application schemas that inherit from different INSPIRE themes. This specific encoding rule defines several conformance classes:
A core conformance class describes common rules that are applied to all the aforementioned conformance classes. Additionally, there are also conformance-class specific rules.
The rules applied in this case to streamline the models were:
If you are interested in knowing more about the conformance class specific rules, just reach out to us at firstname.lastname@example.org!
Want to start transforming data to GeoPackage? Try out our open-source tool, hale»studio today!
The required model transformations for complex GML cases are still under development, and you can expect to see them in the next hale»studio release later this year.