DK - Topology, Geometric Relations
	FAQ Feed

Q10368 -  Can the DK be used to split a polygon with a line? Yes. Refer to the TGIS_Topology.SplitByArc functionality in the DK. The line splitting procedure is demonstrated in the DK SplitByArc sample in DK sample set #5. ... (Modified: 2006-03-01)

Q10253 -  Does the DK support polygon clipping? By this I mean the ability to cut out a smaller subset area from a larger vector map layer, retaining all the attribute information? Yes. The topological operations functionality in the DK v. 7 and subsequent versions of the DK provides for the clipping (cutting ... (Modified: 2004-12-15)

Q10682 -  I have a SHP file layer with many single line shapes. How do I use the DK to split all the lines that intersect with a newly drawn line at the points of intersection? Refer to the TGIS_Topology.SplitByArc functionality in the DK. The line splitting procedure is demonstrated in the DK SplitByArc samp ... (Modified: 2006-03-02)

Q10687 -  What is the most efficient way, using the DK, to find out if a simple line ShapeArc (one part, two points) lies on the perimeter of a ShapePolygon? Use the DK function TGIS_Shape.Relate to determine if a geometric relation between the shape and line is True. Refer to the DK Relation sample in DK sam ... (Modified: 2006-03-15)

Q10741 -  Sometimes, upon closer zoom levels, a smaller polygon shape located inside another polygon disappears. Why? Probably your polygon layer is topologically incorrect. Polygons in the same layer should never overlap. SQL database layers and R-Tree enabled file layers use spatial ... (Modified: 2006-12-13)

Q10249 -  We need to develop a Cadastral GIS, and need the following functions: a) divide a parcel into two new polygons with the input of two coordinate (x,y) values or by creating a new polyline by touching two opposite sides of the polygon and b) to introduce measurements, for a known block of land parcel, ... (Modified: 2003-11-21)

Q10542 -  On the topic of Topological operations, can the DK perform a polygon subtraction, e.g. Polygon A - Polygon B = Remaining Polygon? The following basic topological operations can be performed with the DK: Combine, Union, Intersection, Difference, and SymmetricalDifference (XOR) The DK also supports a ... (Modified: 2004-07-14)

Q10250 -  Can we use the DK to convert an existing layer from line topology to polygon topology, and vice versa? The DK does not support this exact feature out-of-the-box, but the DK topology functionality can be used to develop an application to perform the conversion from line to ... (Modified: 2006-03-02)

Q10469 -  My topology operations are returning very strange results. Can you offer any advice. Please try to enforce the winding check. Shapes must have proper (clock-wise) winding. For example, in this call the last parameter (True) will guarantee a winding check: shp : topologyObj. Combine( shpA, shpB, gisTo ... (Modified: 2003-11-21)

Q10692 -  How can I use the DK to find all points at which polygons in one layer are crossed by lines in another layer? Use the DK function TGIS_Shape.GetCrossings( const _shape : TGIS_Shape ) : TGIS_PointList ... (Modified: 2006-05-11)