Knowledge Base

KB10672 - Convert CAD polyline land parcel data into a topologically correct polygon layer.

Sometimes land parcel maps and other data - typically data associated with AutoCAD (DWG file format) or other CAD software - is composed of vector lines instead of polygon shapes. In such data, the boundaries of each land parcel are formed by a series of lines that cross but do not intersect, providing only an appearance polygon geometry.

The Editor can be used to transform, in a single operation, an entire map layer of such line data into a topologically correct polygon SHP file layer. If the resulting polygon layer must be used in AutoCAD software, use the Editor to convert the SHP file into a DXF file for import into AutoCAD.

The steps are:

  1. Open the polyline layer in the Editor and select (highlight) this layer in the Legend panel.
  2. Click on the Topology toolbar button or use the Tools / Topology menu to open the polyline layer in the Editor Topology Builder window.
  3. Within the Topology Builder window, set the Topology type to be generated to Polygonal.
  4. Generate the polygon SHP file.

The Editor Topology Builder feature can also be used to systematically fix topological errors (missing line intersection nodes, dangling line ends, etc.) in vector line layers, such as to prepare a line layer for routing or other network operations.

Created: January 13, 2006, Modified: September 25, 2015