Knowledge Base

KB10387 - Create a circle or arcing line segment with the DK.

Pursuant to GIS vector rules (and unlike with CAD programs), all shape vectors must be composed of points, with straight line segments connecting the points. Therefore, it is possible to create good looking circles and arcs with the DK, but not with geometric perfection.

Two methods:

  1. Use the DK TGIS_Shape.StrokeArc property to create near perfect circles and arcs with the use of angle parameters in radians.
  2. Use the DK TGIS_Topology class function TGIS_Topology.MakeBuffer to draw a near circle polygon by generating a a buffer around a point.

If the intent is to create the near circle as a line shape (instead of a circle polygon shape), this can be done by copying all points from the polygon to a TGIS_Arc object.

Refer to the DK Circle source code sample in DK sample set #5 for an example of creating a circle. The algorithm used to draw a circle is on MouseUp event (within the sample).

‚ÄčThe TatukGIS Editor product contains special built-in drawing tools for creating circles and other geometric shapes.

Created: September 14, 2005, Modified: December 29, 2015
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