GeoServer layers containing cities in each country, given that all the cities reside in the same table

Question

Using GeoServer, I need to provide a graphical representation of the distribution of some metrics on a geographical basis. The geographical regions will be coloured and labelled according to the value of that metric.

I would like to have a "world" layer (containing all the continents and only continents), a "Europe" layer (containing only countries from Europe) and a "France" layer (containing all the cities in France). So to speak, "a tree of layers containing the immediate children", given that these entities (continents/countries/cities) reside in three distinct tables with one-to-many relationships defined.

I haven't found any "filtering" option when defining a layer from a PostGIS store, so a "cities" layer can only be based on the whole cities table (not on the cities in country X). Is there something I missed ?

P.S. I would rather have distinct layers than having one big layer and filtering with every request, because I think the caching feature can only refer to layers. Is this assumption correct ?

Answer 1

I haven't found any "filtering" option when defining a layer from a PostGIS store, so a "cities" layer can only be based on the whole cities table (not on the cities in country X). Is there something I missed ?

There are basically two ways to filter data in Geoserver: CQL and OGC Filter encoding. Read more: http://docs.geoserver.org/2.0.x/en/user/filter/index.html

The new Geoserver beta additionally supports SQL views (http://gridlock.openplans.org/geoserver/trunk/doc/en/user/data/sqlview.html):

But in your case, I think it would make sense to just create a view containing only cities in France (if you want to avoid creating another table for that).

Answer 2

I don't really understand what you are trying to do but the new SQL views datastore in GeoServer 2.1beta may be what you are looking for. See http://gridlock.openplans.org/geoserver/trunk/doc/en/user/data/sqlview.html