Knowledge Base



KB10253 - Support for polygon clipping.

TatukGIS products (DK and Editor) support polygon clipping (cutting out vector data, retaining all attribute information, from a subset area of a map layer, with options to cut, retain, or exclude any shape geometry laying on the boarder of the clipped area.

The Editor readily supports this within the layer export functionality. Refer to settings in the Layer Export dialog found under menu Layer / Export.

The topological operations functionality in the DK provides for clipping (cutting) a subset area from any vector layer (containing polygons, polylines, or points data) using either a standard rectangle or a custom polygon. Vector layer clipping is generally performed during the layer export procedure.

Clipping using only a simple rectangle

  TGIS_ShapePolygon.GetIntersect(
    const _extent : TGIS_Extent
  ) : TGIS_Shape ;

Clipping using custom polygon shapes

  function TGIS_Topology.CombineShapes (
    const _shpA      : TGIS_Shape ;
    const _shpB      : TGIS_Shape ;   
    const _operation : TGIS_TopologyCombineType
  ) : TGIS_Shape ; 

Using _operation gisTopologyCombineTypeIntersection, the DK can clip polygon (_shpA) with another polygon (_shpB).

The DK Viewer sample (in DK sample set #4) demonstrates use of clipping during vector layer export. The function layer.ImportLayer supports clipping, which means you can copy a selected layer with use of clipping.

Created: December 15, 2004, Modified: December 23, 2015
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