I am using stSPARQL and the ref says:
xsd:float strdf:area(strdf:geometry A): Returns the area of the surface if it is a polygon or multi-polygon.
and so I am trying:
PREFIX geo: <http://geo.linkedopendata.gr/gag/ontology/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX strdf: <http://strdf.di.uoa.gr/ontology#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
...
?municipality geo:has_geometry ?geometry . // so far so good (checked)
FILTER(strdf:area(?geometry) = ?area) .
and I am getting nothing as a result. My overall goal is to get the total area of all municipalities, but I can not even get one! Any idea?
Note that's my first time I am using spatial metric functions, thus what I am trying to do is to collect and show the result of strdf:area()
, but I am failing!
The 1st result of ?geometry is:
"MULTIPOLYGON(((476162.8125 3949684,476195.687499999 3949675,476216.000000001 3949675,476226.1875 3... more
EDIT:
If I try with this: ?area = strdf:area(?geometry) .
, I will get an error:
Encountered " "=" "= "" at line 15, column 9. Was expecting one of: "(" ... "!" ... "^" ... "a" ... ... ...