我有这个RDF文件,我想查询选择单个标记,但我不能.请有人帮助我
<rdf:RDF xmlns="http://www.w3.org/2003/01/geo/wgs84_pos#"
xml:base="http://www.w3.org/2003/01/geo/wgs84_pos"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:foaf="http://xmlns.com/foaf/0.1/"
xmlns:owl="http://www.w3.org/2002/07/owl#"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<owl:NamedIndividual rdf:about="http://www.co-ode.org/ontologies/ont.owl#mark">
<lat rdf:datatype="&xsd;double">121231.0</lat>
<alt rdf:datatype="&xsd;double">2131.0</alt>
</owl:NamedIndividual>