ArcMap

Contour List

Available with Spatial 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 with any cell corner of the input raster, in the processing a shift of the cell alignment of the input raster will be performed to match the specified extent. This shift will trigger a resampling of the input raster using the Bilinear method. Consequently, the output features will be shifted as well, and as a result the 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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