How To: Create polygons from contour polylines


Polygons are created from contour polylines for several reasons, including honoring barriers for better-looking geographical surface representation, offering better contour data visualization, and improving contour data representation for analysis.

The instructions provided describe how to create polygons from contour lines in ArcMap.


There are two options to create polygons from contour polylines. Option A is to use the Feature to Polygon tool while Option B is to use the Polyline To Raster, the Raster to Polygon, and the Dissolve tools.

Apply Option B when Option A fails.

The contour lines must be enclosed line segments before polygons can be created. Trace the lines and manually close the lines or find polylines or paths that close on themselves.

Option A - Apply the Feature to Polygon tool

1. In ArcMap, navigate to ArcCatalog > Toolboxes > System Toolboxes > Data Management > Features > Feature To Polygon.

2. Fill in the parameters and click OK.
The output feature class is shown in the Table Of Contents.

Option B - Apply the Polyline To Raster tool, the Raster to Polygon tool, and the Dissolve tool.

1. Navigate to ArcToolbox > Conversion Tools > To Raster > Polyline To Raster.

2. In the Polyline to Raster dialog box, fill the required parameters.
• Input Features: The polyline input feature dataset to be converted to a raster.
• Value field: Value field allows values to be assigned to the output raster. The field originates from any field in the attribute table of the input feature datasets.
• Output Raster Dataset: The output raster dataset to be created.
• Cellsize (optional): The cell size for the output raster dataset.

3. Click OK to return an output raster.

4. Select the output raster created in step 3 as an input to the Raster to Polygon tool. Navigate to ArcCatalog > Toolboxes > Conversion Tools > From Raster > Raster to Polygon tool.

5. Fill the parameters in the Raster to Polygon tool dialog box.
• Input raster: The input raster dataset must be of integer type.
• Output polygon features: The output feature class contains the converted polygons.

5. Click OK.

6. Select the output created in step 5 to become an input to the Dissolve tool.

7. Navigate to ArcCatalog > Toolboxes > System Toolboxes > Data Management Tools > Generalization > Dissolve to convert the output raster dataset to polygon features.
• Input Features: Aggregates features based on specified attributes.
• Output Feature Class: The feature class to be created contains the aggregated features.

Ensure the pathname of the output feature class does contain special characters.

7. Click OK.

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