Geographical dimensions

[jstcki]

To recap and add more details to what we discussed with @vhf offline:

There will be two kinds of geographical dimensions.

1. Discrete (nominal) values that reference known geographical entities (e.g. Zürich -> Municipality of Zürich, Zürich -> Canton of Zürich)
   • Important here is that it's not necessary to fetch shape data (GeoJSON) with this library. The relevant part is that a known entity is referenced, e.g. https://ld.geo.admin.ch/boundaries/canton/2:2017
   • The main question for me and for this library to solve is how to traverse these links or how to specify which "fields" to include from the linked resource (e.g. the bfsNumber)
2. Continous values that represent coordinates (ie. points on a map)
   • To be usable on the web these must be WGS84 lon/lat value pairs (not sure how this is represented in RDF)
   • Likely, source data will also contain Swiss grid coordinates (either LV03/LV95 or both) -> I expect these to be converted to WGS84 in the data integration step

I hope the requirements are clear, otherwise please let me know!

/cc @ktk @lucguillemot