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- Create the polyline shapefile
| Software environment | Remarks | Methodology |
|---|---|---|
| ArcGIS | Requires 'Advanced' version | Run the ArcGIS ‘Polygon to Polyline’ tool (Toolbox > Data Management Tools > Features > Polygon To Line) with: "Input Features" = (input polygon shapefile); "Output Feature Class" = (as desired); "Identify and store polygon neighboring information (optional)" selected; and all environment settings set as default. Sample input parameters: Sample output: |
| ET GeoWizard free version | Limited to 100 features | Run 'Polygon to Polyline' tool: Sample input parameters: Then run the 'Clean Polylines' tool: Sample input parameters: |
| ET GeoWizards paid version | Not yet evaluated | |
| QGIS | It appears that the QGIS plugin makes polylines around whole polygons, rather than distinct lines between nodes. |
The remaining processes are completed in ArcGIS, regardless of whether ArcGIS or ET GeoWizards was used for the creation of the line shapefile.
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- Close the attribute table, remove the join, and establish a new join basing on RIGHT_FID. Anticipate all records matching.
- This time there should be no need to make a definition query, as there should be no null values.
- Open the output polyline shapefile attribute table.
- Use the Field Calculator to calculate all the RIGHT_Ax values (for the RIGHT_Ax fileds recently added to the polyline shapefile ) equal to the coresponding administrative levels of the polygon shapefile.
- Create a definition query to select the line segments with different LEFT_A0 and RIGHT_A0 attributes.
| Administrative levels in boundary polygon shapefile | Required calculations |
|---|---|
| Administrative level 0 | |
| Administrative levels 0 and 1 | polyline shapefile RIGHT_A0 = polygon shapefile Adm0code |
| Administrative levels 0, 1, and 2 | polyline shapefile RIGHT_A0 = polygon shapefile Adm0code polyline shapefile RIGHT_A1 = polygon shapefile Adm1code |
| Administrative levels 0, 1, 2, and 3 | polyline shapefile RIGHT_A0 = polygon shapefile Adm0code polyline shapefile RIGHT_A1 = polygon shapefile Adm1code polyline shapefile RIGHT_A2 = polygon shapefile Adm2code |
[IF THIS DOES NOT WORK, ENTER ' "LEFT_A0" IS NULL']
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