The TatukGIS Editor supports functionality to convert a layer from line to polygon topology, or from polygon to line topology. This functionality can also systematically remove topology errors (missing line intersection nodes, overlapping polygons, etc.) from line and polygon layers. Refer to the Editor's Topology Builder feature and select the option to build polygonal topology from a polyline layer.
DK topology functionality can be used to implement such functionality (as well as, for example, converting point shapes into line shapes, multi-point shares into single point shapes, etc.) in a DK developed application. Refer to DK methods TGIS_ShapeAsPolygon, TGIS_ShapeAsLine, TGIS_ShapeAsPoint, etc.
Consider if the format of the layer accommodates multiple shape types in the same layer. For example, it would be impossible to convert a line shape(s) in a SHP layer into a polygon shape(s) in the same layer (because each SHP layer can hold only one shape type).