This appears to still yield an empty row for me, my query now looks like
this:
SELECT ?bufferGeom
WHERE {
BIND(
geof:buffer(
"<http://www.opengis.net/def/crs/EPSG/0/3305> POINT(199247.73091
8059595.711024)"^^geo:wktLiteral,
500,
uom:kilometer
) AS ?bufferGeom
)
}
and my output is:
--------------
| bufferGeom |
==============
| |
--------------
Not sure what's going wrong here, I can share more about my setup if that
helps: I'm using a Jena Fuseki server with Geosparl extensions to load my
dataset and RSPARQL as my jena client.
On Sat, Feb 15, 2025 at 5:51 AM Simon Bin <[email protected]>
wrote:
> Hi Sychic,
>
> Try specifying the CRS:
>
> BIND(
> geof:buffer(
> "<http://www.opengis.net/def/crs/EPSG/0/3305> POINT(199247.73091
> 8059595.711024)"^^geo:wktLiteral,
> 500,
> uom:kilometer
> ) AS ?bufferGeom
> )
>
> Cheers,
>
> On Fri, 2025-02-14 at 12:55 -0500, Sychic wrote:
> > Hello,
> > I'm writing asking for some help with using `geo:buffer` and
> > `geo:distance`. I'm working with a dataset using the EPSG 3305 CRS
> > and I'm
> > trying to use geo:buffer to find subjects in the dataset which are
> > within a
> > circular area of a given point. Unfortunately it appears the below
> > query
> > returns no results.
> > ```sparql
> > SELECT ?feature ?label ?wkt
> > WHERE {
> > ?feature skos:prefLabel ?label ;
> > geo:hasGeometry ?geometry .
> > ?geometry geo:asWKT ?wkt .
> >
> > BIND(
> > geof:buffer(
> > "POINT(-5.016805 36.888297)"^^geo:wktLiteral,
> > 500,
> > uom:kilometer
> > ) AS ?bufferGeom
> > )
> >
> > FILTER(
> > geof:sfIntersects(?wkt, ?bufferGeom)
> > )
> > }
> > ```
> > I initially thought the issue may have been with my buffer
> > declaration and
> > upon further inspection, it seems like there was. The following
> > select
> > statement yields an empty line:
> > ```sparql
> > SELECT ?bufferGeom
> > WHERE {
> > BIND(
> > geof:buffer(
> > "POINT(0 0)"^^geo:wktLiteral,
> > 500,
> > uom:meter
> > ) AS ?bufferGeom
> > )
> > }
> > ```
> > I then pivoted to trying to use geo:distance to see if that would
> > work too,
> > however this query also returns nothing:
> > ```sparql
> > SELECT ?dist
> > WHERE {
> > BIND(
> > geof:distance(
> > "POINT(0 0)"^^geo:wktLiteral,
> > "POINT(0 1)"^^geo:wktLiteral,
> > uom:meter
> > ) AS ?dist
> > )
> > }
> > ```
> > I'm using Jena Fuseki Geosparql 5.3.0 to load my data and Apache Jena
> > 5.3.0
> > to execute my SPARQL queries.
> > Hoping for some assistance,
> > Sychic
>
>
>
