On 19.04.20 14:55, Andy Seaborne wrote:
> The rdflib output now shows ^^ on the literals so something has
> changed. maybe it does not print the URI the way you are printing the
> data.
>
> The rdflib project prefer their questions to go to stackoverflow with
> the tag "rdflib" but before that the URIs for functions and properties
> need sorting out.
>
> GEO[] isn't provided by rdflib.
Well, I hope and guess the TO created the namespace object before using
it in the code via
|GEO = Namespace('http://www.opengis.net/ont/geosparql#')|
which is also a Python dictionary, thus, you can call
|GEO['wktLiteral']|
Clearly, more intended by the API would be to call
|GEO.wktLiteral|
but, yeah - very much off-topic.
Regarding the equals function, I set up a sample and can say that
equality isn't what people would probably expect, i.e. even
|PREFIX geo: <http://www.opengis.net/ont/geosparql#>||
||PREFIX geof: <http://www.opengis.net/def/function/geosparql/>||
||PREFIX uom: <http://www.opengis.net/def/uom/OGC/1.0/>||
||PREFIX ex: <http://example.org/>||
||SELECT *||
||WHERE {||
|| BIND((geof:sfEquals("POINT(-0.0754 51.5055)"^^geo:wktLiteral,
"POINT(-0.0754 51.5055)"^^geo:wktLiteral)) as ?equals)||
|| BIND((geof:distance("POINT(-0.0754 51.5055)"^^geo:wktLiteral,
"POINT(-0.0754 51.5055)"^^geo:wktLiteral, uom:metre)) as ?dist)||
||}|
returns (unexpectedly?) "false" although being the same geometry object
and a (expected) distance of 0.0e0. The implementation is using JTS and
according to the docs:
> The three equals relations (/sfEquals/, /ehEquals/ and /rccEquals/)
> use spatial equality and not lexical equality. Therefore, some
> comparisons using these relations may not be as expected.
>
> The JTS description of /sfEquals/ is:
>
> * True if two geometries have at least one point in common and no
> point of either geometry lies in the exterior of the other geometry.
>
> Therefore, two empty geometries will return false as they are not
> spatially equal. Shapes which differ in the number of points but have
> the same geometry are equal and will return true.
>
> e.g. |LINESTRING (0 0, 0 10)| and |LINESTRING (0 0, 0 5, 0 10)| are
> spatially equal.
>
so, I doubt using equals is a useful test here. Nevertheless, GeoSPARQL
itself is working as expected, I tried several common queries. As long
as you have the correct data loaded ...
Lorenz
>
> Andy
>
> On 19/04/2020 12:44, Lorenz Buehmann wrote:
>> why are you asking about Python based rdflib code on this mailing list?
>> I mean, it's a totally different API. And what is the purpose of the
>> code?
>>
>> honestly, you should start with a minimal example. Load a sample of RDF
>> triples with the correct datatype, then try the queries. You should also
>> check again about GeoSPARQL.
>>
>> Also, in the specs the URI is geo:sfEquals for the propertyand
>> geof:sfEquals to use it as a function. Where did you read about the
>> usage of the URI geo:equals ?
>>
>>
>> And as Andy already pointed out, the literal that you use for matching
>> also needs the datatype.
>>
>> On 18.04.20 18:47, manoj deshpande wrote:
>>> I am trying to convert "POLYGON(())" wkt value from string to
>>> "wktLiteral"
>>> as suggested above in below code (python rdflib).
>>>
>>> if name == "wkt":
>>> self._graph.add((image, GEO["asWKT"], rl.Literal(value,
>>> datatype=GEO["wktLiteral"])))
>>>
>>>
>>> Is it right method ?
>>>
>>> As I see below values when I execute query. The wktliteral value is
>>> not appended in the end.
>>>
>>>
>>> "POLYGON((8.461714982986452 48.997849415191105,8.461714982986452
>>> 48.99797963751407,8.461988568305971
>>> 48.99797963751407,8.461988568305971
>>> 48.997849415191105,8.461714982986452 48.997849415191105))"^^
>>>
>>>
>>> Thanks,
>>>
>>> Manoj
>>>
>>>
>>> On Sat, Apr 18, 2020 at 3:47 PM Andy Seaborne <[email protected]> wrote:
>>>
>>>> The literal need to have a datatype
>>>>
>>>> "POLYGON((...))"^^<http://www.opengis.net/ont/geosparql#wktLiteral>
>>>>
>>>> judging by your first message, they are strings.
>>>>
>>>> Andy
>>>>
>>>> On 18/04/2020 13:03, manoj deshpande wrote:
>>>>> I tried below query as per suggestion, But this also returns me no
>>>> results.
>>>>> Is the query is right ??
>>>>>
>>>>> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
>>>>> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
>>>>> PREFIX geo: <http://www.opengis.net/ont/geosparql#>
>>>>> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
>>>>> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
>>>>> PREFIX : <http://example.org/#>
>>>>> PREFIX geo: <http://www.opengis.net/ont/geosparql#>
>>>>> PREFIX spatial: <http://jena.apache.org/spatial#>
>>>>> SELECT ?object
>>>>> WHERE {
>>>>> GRAPH <http://project/base/default> {
>>>>> ?subject geo:asWKT ?object FILTER ( geo:equals(?object,
>>>>> "POLYGON((8.463699817657472 48.99872928913063,8.463887572288515
>>>>> 48.998644821906865,8.46399486064911
>>>>> 48.998764483764916,8.46425771713257
>>>>> 48.99865538031766,8.464375734329225
>>>>> 48.998746886450874,8.463919758796694
>>>>> 48.99893693711346,8.463699817657472 48.99872928913063))"))
>>>>> } }
>>>>>
>>>>>
>>>>> *Results*
>>>>>
>>>>> {
>>>>> "head": {
>>>>> "vars": [ "object" ]
>>>>> } ,
>>>>> "results": {
>>>>> "bindings": [
>>>>>
>>>>> ]
>>>>> }
>>>>> }
>>>>>
>>>>> Thanks & Regards
>>>>> Manoj
>>>>>
>>>>> On Sat, Apr 18, 2020 at 12:27 PM Lorenz Buehmann <
>>>>> [email protected]> wrote:
>>>>>
>>>>>> geo:equals is a filter function and not a property function. This
>>>>>> means
>>>>>> it returns a boolean value, thus, you have to use it in a FILTER
>>>>>>
>>>>>> (untested)
>>>>>>
>>>>>> FILTER(geo:equals(?object,
>>>>>> "POLYGON((8.463699817657472
>>>>>> 48.99872928913063,8.463887572288515
>>>>>> 48.998644821906865,8.46399486064911
>>>>>> 48.998764483764916,8.46425771713257
>>>>>> 48.99865538031766,8.464375734329225
>>>>>> 48.998746886450874,8.463919758796694
>>>>>> 48.99893693711346,8.463699817657472
>>>>>> 48.99872928913063))"
>>>>>> )
>>>>>> )
>>>>>>
>>>>>>
>>>>>> On 18.04.20 12:19, manoj deshpande wrote:
>>>>>>> I am using Apache Jena Fuseki Server for Storing Geo Coordinates of
>>>>>>> location. How to find out that if two polygons or two rectangles
>>>>>>> intersect each other inside Fuseki.
>>>>>>>
>>>>>>> I have stored geocoordinates in WKT serialization format. When I
>>>>>>> execute below query
>>>>>>>
>>>>>>> |*PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX rdf:
>>>>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX geo:
>>>>>>> <http://www.opengis.net/ont/geosparql#> PREFIX xsd:
>>>>>>> <http://www.w3.org/2001/XMLSchema#> PREFIX rdfs:
>>>>>>> <http://www.w3.org/2000/01/rdf-schema#> PREFIX :
>>>>>>> <http://example.org/#> PREFIX geo:
>>>>>>> <http://www.opengis.net/ont/geosparql#> PREFIX spatial:
>>>>>>> <http://jena.apache.org/spatial#> SELECT ?object WHERE { GRAPH
>>>>>>> <http://project/base/default> { ?subject geo:asWKT ?object . }
>>>>>>> }*|||
>>>>>>> I get these below results.
>>>>>>> |object 1 "POLYGON((8.463699817657472
>>>>>>> 48.99872928913063,8.463887572288515
>>>>>>> 48.998644821906865,8.46399486064911
>>>>>>> 48.998764483764916,8.46425771713257
>>>>>>> 48.99865538031766,8.464375734329225
>>>>>>> 48.998746886450874,8.463919758796694
>>>>>>> 48.99893693711346,8.463699817657472 48.99872928913063))" 2
>>>>>>> "POLYGON((8.463560342788698 48.99847940651206,8.463560342788698
>>>>>>> 48.99864834137738,8.46377491950989
>>>>>>> 48.99864834137738,8.46377491950989
>>>>>>> 48.99847940651206,8.463560342788698 48.99847940651206))" 3
>>>>>>> "POLYGON((8.463447690010073 48.99835974396915,8.463447690010073
>>>>>>> 48.99849348443939,8.463646173477175
>>>>>>> 48.99849348443939,8.463646173477175
>>>>>>> 48.99835974396915,8.463447690010073 48.99835974396915))" 4
>>>>>>> "POLYGON((8.463254570961 48.99821544463795,8.463254570961
>>>>>>> 48.99838438039854,8.463635444641115
>>>>>>> 48.99838438039854,8.463635444641115
>>>>>>> 48.99821544463795,8.463254570961
>>>>>>> 48.99821544463795))" 5 "POLYGON((8.463689088821413
>>>>>>> 48.99826823712468,8.463689088821413
>>>>>>> 48.99845477012966,8.46402168273926
>>>>>>> 48.99845477012966,8.46402168273926
>>>>>>> 48.99826823712468,8.463689088821413
>>>>>>> 48.99826823712468))" 6 "POLYGON((8.463892936706545
>>>>>>> 48.99843013373508,8.463892936706545
>>>>>>> 48.998588510344774,8.464316725730898
>>>>>>> 48.998588510344774,8.464316725730898
>>>>>>> 48.99843013373508,8.463892936706545 48.99843013373508))" 7
>>>>>>> "POLYGON((8.463093638420107 48.99805354732974,8.463093638420107
>>>>>>> 48.998243600637835,8.463737368583681
>>>>>>> 48.998243600637835,8.463737368583681
>>>>>>> 48.99805354732974,8.463093638420107 48.99805354732974))" 8
>>>>>>> "POLYGON((8.463619351387026 48.99797963751407,8.463619351387026
>>>>>>> 48.998180249615714,8.464118242263796
>>>>>>> 48.998180249615714,8.464118242263796
>>>>>>> 48.99797963751407,8.463619351387026 48.99797963751407))" 9
>>>>>>> "POLYGON((8.464407920837404 48.998303432084754,8.464407920837404
>>>>>>> 48.99857443244431,8.46477270126343
>>>>>>> 48.99857443244431,8.46477270126343
>>>>>>> 48.998303432084754,8.464407920837404 48.998303432084754))" 10
>>>>>>> "POLYGON((8.464225530624391 48.99806762537742,8.464225530624391
>>>>>>> 48.99839141937611,8.464820981025698
>>>>>>> 48.99839141937611,8.464820981025698
>>>>>>> 48.99806762537742,8.464225530624391 48.99806762537742))"|
>>>>>>> |Then later I want to filter out these geo:WKT objects based on
>>>>>>> geo:intersection (Intersection or equals or contains methods).
>>>>>>> And I
>>>>>>> updated my query as below. |
>>>>>>> |
>>>>>>> |*PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX rdf:
>>>>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX geo:
>>>>>>> <http://www.opengis.net/ont/geosparql#> PREFIX xsd:
>>>>>>> <http://www.w3.org/2001/XMLSchema#> PREFIX rdfs:
>>>>>>> <http://www.w3.org/2000/01/rdf-schema#> PREFIX :
>>>>>>> <http://example.org/#> PREFIX geo:
>>>>>>> <http://www.opengis.net/ont/geosparql#> PREFIX spatial:
>>>>>>> <http://jena.apache.org/spatial#> SELECT ?object WHERE { GRAPH
>>>>>>> <http://project/base/default> { ?subject geo:asWKT ?object .
>>>>>>> ?object
>>>>>>> geo:equals "POLYGON((8.463699817657472
>>>>>>> 48.99872928913063,8.463887572288515
>>>>>>> 48.998644821906865,8.46399486064911
>>>>>>> 48.998764483764916,8.46425771713257
>>>>>>> 48.99865538031766,8.464375734329225
>>>>>>> 48.998746886450874,8.463919758796694
>>>>>>> 48.99893693711346,8.463699817657472 48.99872928913063))" } } *|
>>>>>>> |Which should result me atleast the coordinates of first geo object
>>>>>>> which really equals the POLYGON coordinates but I get empty
>>>>>>> results as
>>>>>>> shown in below image. Please suggest me where I am getting it
>>>>>>> wrong.**|
>>>>>>> But I get no results as attached in snapshot. Please help me
>>>>>>> regarding
>>>>>> this.|
>>>>>>
>>
