A post and 2 tutorials on single-file open geospatial standards

[florisvdh]

I believe it is time to introduce these formats to scientists so that they learn and implement their usage.

[florisvdh]

To ease reviewing, herewith the compiled html versions.

[hansvancalster]

Very nice work!! 👍

I have some suggestions, but it is up to you to decide how to deal with them.

[florisvdh]

Thanks @hansvancalster for reviewing. Regarding putting GPKG after GeoJSON, I have some counterideas, so I'll await other people's ideas:

• GeoPackage is more universal to all usecases, and much propagated by the developers and writers in the R Spatial ecosystem as a replacement of shapefiles. For example, it led Roger Bivand to move his rgrass7 package to use GPKG as an intermediate format, instead of shapefiles.
• GeoJSON, though universal and having a simple approach (text), brings its own limitations: it's not a database, it gets inflated with more complex data. And for the tutorial it needs a bit more intricate explanation than GPKG (which works out of the box) because its versions / CRS approach.

It's a good idea to show how to add multiple layers in GPKG, I'll add that.

Regarding rasters in a GPKG, it seems I only tried it with a GRTS master grid - and that means my footnote in the article has a mistake (I've messed up with RasterLite here, will fix it). I was coping at that time with very large numbers (Int32 GRTS addresses), which is supported by GeoTIFF but not by GPKG. (And the RasterLite alternative got so inflated with larger rasters (file size) compared to GeoTIFF (really a lot) that that option was not good enough to me).

So yes, I'll give GPKG another try for rasters, with more simple data; I'm curious whether it is better at filesize than RasterLite (which is also an SQLite implementation).

Anyhow, for vector data GPKG was much more efficient in filesize than SpatiaLite (another SQLite implementation). Both RasterLite and SpatialLite exist longer but clearly GPKG is now preferred and it is the only one which is embraced and maintained by the OGC consortium.

[florisvdh]

Long live git. It seems I did an experiment with rasters in GPKG (although obsoleted it because of the unsupported Int32 type). See these lines. And the conclusion was: GPKG filesize can even be smaller than GeoTIFF 😃 !

Some work is to be done, obviously. It may even be better to split off GPKG in a separate tutorial, combining vector & raster, or perhaps just add another GPKG section in the raster tutorial. Actually I prefer the latter, hence keeping vector & raster separated; mixing up both will complicate matters and make it more difficult to the reader.

[ThierryO]

Nice tutorial. I've a few comments.

[florisvdh]

Herewith newly compiled html output.

[hansvancalster]

Great post! I very much appreciate the extra effort you have put into this. The comparison tables are great and each of the tutorials are very instructive. 👍

[peterdesmet]

Is this online yet? Wanna read it. 😄

[florisvdh]

Just 😉