ArcMap

Contour List

Available with Spatial Analyst license.

Available with 3D Analyst license.

Summary

Creates a feature class of selected contour values from a raster surface.

Learn more about how Contouring works

Usage

  • Contours do not extend beyond the spatial extent of the raster, and they are not generated in areas of NoData; therefore, adjacent contour inputs should first be edgematched into a continuous feature dataset. As an alternative to edgematching, you can merge the adjacent rasters before computing contours.

  • Contours can be generated in areas of negative raster values. The contour values will be negative in such areas. Negative contour intervals are not allowed.

  • The contour values do not need to be sorted in order.

  • Smoother but less accurate contours can be obtained by preprocessing the input raster with a Focal Statistics operation with the MEAN option or the Filter tool with the LOW option.

  • If Extent is specified in the environment setting and the lower-left corner of the output extent does not match any cell corner of the input raster, during processing, a shift of the cell alignment of the input raster will occur to match the specified extent. This shift will trigger a resampling of the input raster using the Bilinear method. Consequently, the output features will shift as well, and the resultant output features may not overlay the original input raster exactly. You can avoid this shift by using the input raster as the Snap Raster in the environment.

  • See Analysis environments and Spatial Analyst for additional details on the geoprocessing environments that apply to this tool.

Syntax

ContourList (in_raster, out_polyline_features, contour_values)
ParameterExplanationData Type
in_raster

The input surface raster.

Raster Layer
out_polyline_features

The output contour polyline features.

Feature Class
contour_values
[contour_value,...]

List of z-values for which to create contours.

Double

Code sample

ContourList example 1 (Python window)

This example creates contours for three elevation values from an Esri Grid raster and outputs them as a shapefile.

import arcpy
from arcpy import env  
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
ContourList("elevation", "C:/sapyexamples/output/outcontourlist.shp", [600, 935, 1237.4])
ContourList example 2 (stand-alone script)

This example creates contours for three elevation values from an Esri Grid raster and outputs them as a shapefile.

# Name: ContourList_Ex_02.py
# Description: CCreates contours or isolines based on a list of contour values.
# Requirements: Spatial Analyst Extension

# Import system modules
import arcpy
from arcpy import env
from arcpy.sa import *

# Set environment settings
env.workspace = "C:/sapyexamples/data"

# Set local variables
inRaster = "elevation"
contourIntervalList = [600, 935, 1237.4]
outContours = "C:/sapyexamples/output/outcontourlist02.shp"

# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")

# Execute ContourList
ContourList(inRaster, outContours, contourIntervalList)

Environments

Licensing information

  • ArcGIS Desktop Basic: Requires Spatial Analyst or 3D Analyst
  • ArcGIS Desktop Standard: Requires Spatial Analyst or 3D Analyst
  • ArcGIS Desktop Advanced: Requires Spatial Analyst or 3D Analyst

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