Using GeoSpatial nearby feature

lavhal · May 23, 2019, 8:51am

Hi,

I am trying to use the Stardog GeoSpatial nearby feature. My use case is that I have to retrieve latitude and longitude for a number of different locations and should pass them as parameters to the nearby function to find nearby places, such in the following query:

PREFIX : http://api.stardog.com/
PREFIX owl: http://www.w3.org/2002/07/owl#
PREFIX rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#
PREFIX rdfs: http://www.w3.org/2000/01/rdf-schema#
PREFIX stardog: tag:stardog:api:
PREFIX xsd: http://www.w3.org/2001/XMLSchema#
prefix wgs84_pos: http://www.w3.org/2003/01/geo/wgs84_pos#
prefix geo: http://www.opengis.net/ont/geosparql#
prefix geof: http://www.opengis.net/def/function/geosparql/
prefix unit: http://qudt.org/vocab/unit#

select * {

GRAPH <graph1> {

?place a :Place;
wgs84_pos:lat ?lat;
wgs84_pos:long ?long.

    ?s  
           geof:nearby (?lat ?long 22 unit:Kilometer);
           wgs84_pos:lat ?pp_lat;
           wgs84_pos:long ?pp_long.

}

After running the above query, I am getting the error:

Caused by: java.lang.IllegalStateException: Latitude must be a double value between -90 & 90

I also tried the following ways, including binding latitude and longitude directly, e.g.

     BIND(xsd:float("50.173588") AS ?lat).
     BIND(xsd:float("12.12583") AS ?long).

:

PREFIX : http://api.stardog.com/
PREFIX owl: http://www.w3.org/2002/07/owl#
PREFIX rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#
PREFIX rdfs: http://www.w3.org/2000/01/rdf-schema#
PREFIX stardog: tag:stardog:api:
PREFIX xsd: http://www.w3.org/2001/XMLSchema#
prefix wgs84_pos: http://www.w3.org/2003/01/geo/wgs84_pos#
prefix geo: http://www.opengis.net/ont/geosparql#
prefix geof: http://www.opengis.net/def/function/geosparql/
prefix unit: http://qudt.org/vocab/unit#

select * {

GRAPH <graph1> {
?place a :Place;
wgs84_pos:lat ?lat;
wgs84_pos:long ?long.
BIND(strdt(concat('Point(', STR(?long), ' ', STR(?lat), ')' ), geo:wktLiteral) as ?location)
?s
geof:nearby (?location 22 unit:Kilometer);
wgs84_pos:lat ?poi_lat;
wgs84_pos:long ?poi_long.
}
}

The above query does not return any result.

The queries that are returning results, but are only for a particular point, i.e. latitude and longitude, respectively, are:

PREFIX : http://api.stardog.com/
PREFIX owl: http://www.w3.org/2002/07/owl#
PREFIX rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#
PREFIX rdfs: http://www.w3.org/2000/01/rdf-schema#
PREFIX stardog: tag:stardog:api:
PREFIX xsd: http://www.w3.org/2001/XMLSchema#
prefix wgs84_pos: http://www.w3.org/2003/01/geo/wgs84_pos#
prefix geo: http://www.opengis.net/ont/geosparql#
prefix geof: http://www.opengis.net/def/function/geosparql/
prefix unit: http://qudt.org/vocab/unit#

select * {

GRAPH <graph1> {
?s
geof:nearby ("Point(12.12583 50.173588 )"^^geo:wktLiteral 22 unit:Kilometer);
wgs84_pos:lat ?poi_lat;
wgs84_pos:long ?poi_long.
}
}

and (note the switching between longitude and latitude):

PREFIX : http://api.stardog.com/
PREFIX owl: http://www.w3.org/2002/07/owl#
PREFIX rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#
PREFIX rdfs: http://www.w3.org/2000/01/rdf-schema#
PREFIX stardog: tag:stardog:api:
PREFIX xsd: http://www.w3.org/2001/XMLSchema#
prefix wgs84_pos: http://www.w3.org/2003/01/geo/wgs84_pos#
prefix geo: http://www.opengis.net/ont/geosparql#
prefix geof: http://www.opengis.net/def/function/geosparql/
prefix unit: http://qudt.org/vocab/unit#

select * {

GRAPH <graph1> {
?s
geof:nearby (50.173588 12.12583 22 unit:Kilometer);
wgs84_pos:lat ?poi_lat;
wgs84_pos:long ?poi_long.
}
}

I imagine, I am doing something wrong.

Best,

lavhal · May 24, 2019, 2:20pm

Hi,

any idea on this?

Best,

stephen · May 24, 2019, 4:25pm

Do you have spatial.enabled=true on your database? If so and this still isn't working correctly, could you share a minimal data set that we can run this query on to reproduce?

lavhal · May 27, 2019, 6:42am

Yes, the spatial.enabled=true is already set, since I am able to use the nearby feature when passing static values.

Here is an example:

@prefix : <http://api.stardog.com/> .
@prefix geo: <http://www.opengis.net/ont/geosparql#> .
@prefix unit: <http://qudt.org/vocab/unit#> .
@prefix geof: <http://www.opengis.net/def/function/geosparql/> .
@prefix wgs84_pos: <http://www.w3.org/2003/01/geo/wgs84_pos#> .

<http://example.com#512fab7de4b00f42967fd020> wgs84_pos:lat "50.173737"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.128104"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#513a218de4b08d57cd897e1f>
wgs84_pos:lat "50.173588"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.12583"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#5194a048498eeaa61aff2467>
wgs84_pos:lat "50.163685"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.133927"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#5283698611d281aae780e010>
wgs84_pos:lat "50.162033"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.136862"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#4c57f70f12f0d13adf3208ad>
wgs84_pos:lat "50.177277"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.137034"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#4caf305ddb32f04dea39b54d>
wgs84_pos:lat "50.17106"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.125232"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#4de005aa8877aab7fe3fd8d1>
wgs84_pos:lat "50.16986"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.129593"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#4fdf1c9ae4b08aca4a285b9f>
wgs84_pos:lat "50.171318"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.131139"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#5040e589e4b0f300413e2cba>
wgs84_pos:lat "50.176285"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.13285"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#5087a8c8e4b089a9f01b1a5e>
wgs84_pos:lat "50.17568"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.116262"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#50f5d5d9e4b03e61710cc0d3>
wgs84_pos:lat "50.164627"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.137802"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#510b7308e4b0428ec8a7c3c8>
wgs84_pos:lat "50.17561"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.136623"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#504d82dbe4b0f7c8cf947745>
wgs84_pos:lat "50.1665"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.147203"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#50d335713d7c145df3e86a29>
wgs84_pos:lat "50.167995"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.12033"^^<http://www.w3.org/2001/XMLSchema#float> .

<http://example.com#511ac86ba629ec8f68cf493c>
wgs84_pos:lat "50.173923"^^<http://www.w3.org/2001/XMLSchema#float> ;
wgs84_pos:long "12.126574"^^<http://www.w3.org/2001/XMLSchema#float> .

dlbis · May 27, 2019, 11:54am

Hi,

I have been using with success the nearby function but I have included Geometry instances instead of separate lat and long properties. The Geometry instances have the lat and long properties however.

In the following query, I am getting Geometry instances that are 5 km or less from a chosen Geometry.

select ?prop1Addr ?prop2Addr ?distance
where {
values(?geom1) {(http://www.domain.com/PropertyGeom/ee48fa00c63952a8a48d8e66540aa695)}
?geom1 wgs:lat ?prop1Lat; wgs:long ?prop1Long .
?geom2 geof:nearby (?geom1 5 unit:Kilometer) .
filter (?geom1 != ?geom2)
?prop1 geo:hasGeometry ?geom1; onto:Property-streetAddress ?prop1Addr .
?prop2 geo:hasGeometry ?geom2; onto:Property-streetAddress ?prop2Addr .
bind(geof:distance(?geom1, ?geom2, unit:Meter) as ?distance)
}
order by ?distance

lavhal · May 27, 2019, 3:36pm

Hi Daniel,

good to know that, thank you for your hint.

I also tried with binding the location as goe:wktLiteral e.g. BIND(strdt(concat('Point(', STR(?long), ' ', STR(?lat), ')' ), geo:wktLiteral) as ?location) , and passing as a parameter, as it shown in the second query above, unfortunately didn't work.

lavhal · May 28, 2019, 10:01am

The following query is working fine (after associating ?place with type of :Location), which basically I can adopt for my use case, although the issue with passing directly latitude and longitude remains.

PREFIX : <http://api.stardog.com/>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX stardog: <tag:stardog:api:>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
prefix wgs84_pos: <http://www.w3.org/2003/01/geo/wgs84_pos#>
prefix geo: <http://www.opengis.net/ont/geosparql#>
prefix geof: <http://www.opengis.net/def/function/geosparql/>
prefix unit: <http://qudt.org/vocab/unit#>

select * {

GRAPH  <graph1>  {
?place a ?type;
          wgs84_pos:lat ?lat;
          wgs84_pos:long ?long.
          geof:nearby (50.173588 12.12583 2 unit:Kilometer) .
?s
     geof:nearby (?place 2 unit:Kilometer);
     wgs84_pos:lat ?poi_lat;
    wgs84_pos:long ?poi_long.
  }
}

There is a mistake that I was doing, such as the following query:

PREFIX : <http://api.stardog.com/>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX stardog: <tag:stardog:api:>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
prefix wgs84_pos: <http://www.w3.org/2003/01/geo/wgs84_pos#>
prefix geo: <http://www.opengis.net/ont/geosparql#>
prefix geof: <http://www.opengis.net/def/function/geosparql/>
prefix unit: <http://qudt.org/vocab/unit#>

select * {

GRAPH  <graph1>  {
?place 
          wgs84_pos:lat ?lat;
          wgs84_pos:long ?long.
          geof:nearby (50.173588 12.12583 2 unit:Kilometer) .
?s
     geof:nearby (?place 2 unit:Kilometer);
     wgs84_pos:lat ?poi_lat;
    wgs84_pos:long ?poi_long.
  }
}

Note the differences between two queries, in the second one, the clause a ?type is missing after the ?place variable, which causes only latitude and longitude to be retrieved.

Thank you for your support.

system · June 11, 2019, 10:01am

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Using GeoSpatial nearby feature

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