PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> 
PREFIX geo: <http://www.w3.org/2003/01/geo/wgs84_pos#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
prefix sturm: <https://xtriples.lod.academy/sturm/>

SELECT ?letterlabel ?place ?desc ?long ?lat 
WHERE
{
  	?letter rdfs:label ?letterlabel .
  	?letter rdf:type ?lettertype .
  	?lettertype rdfs:label ?lettertypelabel .
  	?letter sturm:mentions ?mention .
	?mention rdf:type geo:SpatialThing .
 
  OPTIONAL {
    ?sender sturm:sends ?letter .
    ?letter rdfs:label ?letterlabel .
    ?letter rdf:type ?lettertype .
    ?lettertype rdfs:label ?lettertypelabel .
    ?sender rdfs:label ?sendername .
    BIND(concat(str(?lettertypelabel), " ", str(?letterlabel)," sent from ", str(?sendername)) as ?desc) .
  }
  
  OPTIONAL {
    ?letter sturm:mentions ?mention .
	?mention rdf:type geo:SpatialThing .
    ?mention rdfs:label ?place.
  }
  
  OPTIONAL {
    ?letter sturm:mentions ?mention .
	?mention rdf:type geo:SpatialThing .
    ?mention geo:lat ?lat .
  }
  
  OPTIONAL {
    ?letter sturm:mentions ?mention .
	?mention rdf:type geo:SpatialThing .
    ?mention geo:long ?long .
  }
}