I have just joined this group (it took some time to get through the subscription process). I hope the group will come to life soon, I think its subject is both interesting and important.
Here is one thing that I think would be good to share our thoughts on: the method of specification of the Coordinate Reference System (CRS), also known as the Spatial Reference System (SRS), in spatial Linked Data. I have been following and commenting on the GeoSPARQL specification, and this is one thing that I think I wish would have been different: In GeoSPARQL The CRS can be indicated by a URI (which is good), but that URI is concatenated with the coordinates in the literal that describes the geometry. I think it would have been much nicer if the CRS could be published as a separate triple. For one thing, it would allow consumers of data to use the CRS as a filter in SPARQL queries.
I wonder what the other group members think of this issue.