anchor.diff:  WKT can also describe coordinate reference systems (CRS) and projections. 
   One common source of confusing is that, by default, the X-coordinate (longitude)is followed by Y-coordinate (latitude) 
   while many people are used to the Y-X (latitude-longitude) notation.
  -
  -=== Reading WKT Literals
  -
  -=== Writing WKT Literals
  -
  -RDF4j 2.1.x uses Spatial4J 0.4.1, which does not support writing shapes to WKT just yet (added in 0.5).
  -
  -An extremely simple writer could look like:
  -
  -[source,java]
  -----
  -public static String toWkt(Point p) {
  -   return "POINT(" + p.getX() + " " + p.getY() + ")";
  -}
  -----
  -
  -== Queries
  -
  -=== Simple shapes
   
   Spatial4j provides some convenience functions for generating simple geometric shapes.
   For instance, points representing the center of the cities of Amsterdam, Brussels... can easily be generated using `SpatialContext.GEO`.
  
positive.code:                       res.getValue("dist").stringValue() + "km");   } );
  ----
  
  ===
  
  == Further reading
  
  
negative.code: ----
  
  Circles and rectangles are also supported, polygons require JTS to be present.
  
  === Reading WKT Literals
  
  === Writing WKT Literals
  
  RDF4j 2.1.x uses Spatial4J 0.4.1, which does not support writing shapes to WKT just yet (added in 0.5).
  
  An extremely simple writer could look like:
  
  [source,java]
  ----
  public static String toWkt(Point p) {
     return "POINT(" + p.getX() + " " + p.getY() + ")";
  }
  ----
  
  
  == Queries
  
  === Distance query
  
  