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Polygon to Line

Overview​

The Polygon to Line tool extracts outer boundaries and inner hole outlines from input polygon features (Polygon or MultiPolygon). The process converts closed polygon geometries into corresponding line geometries, reducing the data structure from polygon to line.

Use Cases​

  • Data format conversion: Convert polygon objects from CAD systems into GIS vector line features.
  • Thematic map production: Generate independent boundary outline layers for parcels, lakes, or administrative areas for dashed or specialized line styling.
  • Spatial analysis preprocessing: Convert building footprints to line features for buffer analysis or accessibility calculation.
  • Boundary statistics: Extract parcel perimeters and combine them with field attributes to calculate total boundary length by category.

Parameters​

ParameterDescriptionNotes
Input featureSource polygon feature dataset whose boundaries will be extracted.Must be polygon features.
Output pathFolder where the result is stored.Select a target folder.
Output file nameName of the output line feature dataset.Text without a file extension.

Steps​

  1. Start the tool: Open the Geoprocessing Toolbox, go to Vector Tools > Feature Conversion, and open the Polygon to Line tool pane.
  2. Set input: Select the input feature layer to process.
  3. Configure parameters: If needed, configure field retention rules in the advanced settings.
  4. Configure output: Specify the output path and file name.
  5. Run the tool: Click Run. The generated outline lines are added automatically.

Notes​

  • Attribute integrity: Generated line features inherit all attributes from their source polygon features. If a polygon contains inner rings (holes), the extracted polylines share the same attribute ID.
  • Topological overlap: If input polygon features share edges, the converted line dataset will contain fully overlapping line records at those locations. Consider running Delete Duplicates after processing.
  • Data correction: Self-intersecting polygon features may cause incomplete boundary extraction. iXGIS recommends running Repair Geometry first and processing data in a projected coordinate system.