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  1. Spatial Information Systems
  2. SIS-163

Unsupported WKT 2 features



    • Task
    • Status: Open
    • Minor
    • Resolution: Unresolved
    • 0.4, 0.5, 0.6
    • None
    • Referencing
    • None


      This page summarizes the WKT 2 features which are currently not supported in Apache SIS. More details are provided in the sub-tasks for unsupported elements and restrictions. The third sections is about recommendations that are not mandatory, but that we do not yet follow.

      Unsupported WKT elements

      • ParametricCRS (we need an implementation in the rest of SIS first).
      • Bearing element for polar coordinate systems having a "clockwise" or "counterClockwise" axis direction.
      • BoundCRS element as the successor of the WKT 1 TOWGS84 element.
      • Time extent with named eras (e.g.TIMEEXTENT["Jurassic", "Quaternary"])

      Restrictions that we do not verify

      • ISO 19162 restrictions on CompoundCRS: (geographic or projected or engineering) followed by (vertical or parametric) followed by temporal. (edit: fixed)
      • ISO 19162 restrictions on axis name, abbreviation and directions (e.g. geographic CRS shall be ‘latitude’, ‘longitude’).
      • Precedence of EPSG codes over names for Conversion objects.

      Recommendations that we do not yet follow

      • Formatter should be able to write the short WKT 2 keywords (currently we format only the long ones, because they match the type names). (edit: fixed)
      • We do not check the recommended maximum string lengths (80 characters in names, 255 characters in other quoted texts, 4096 in total).


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              Unassigned Unassigned
              desruisseaux Martin Desruisseaux
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