Selon Martin Landa <[email protected]>: > Hi, > > I am working with three points which define a full circle. To describe > it using OGRCircularString > I would need five points defining two circular arcs, right? So in my > case to compute an intermediate point for the second arc, right?
Martin, You can describe a full circle with 3 points by specifying (P1,P2,P1) where P1-P2 defines a diameter of the circle, but there's an ambiguity on the orientation to follow the CircularString (which shouldn't matter if the CircularString is part of a CurvePolygon) and some implementation might not like it (OGR should be fine) Indeed using 5 points is better. You can define (P1,P2,P3,P4,P1) where all points are on the circle. For example P1-P3 and P2-P4 being 2 diameters, but that's not a requirement. Even -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
