Contour List (Spatial Analyst)

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. Edgematch adjacent contour inputs into a continuous feature dataset first. 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 those 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 using the Focal Statistics tool with the Mean option or the Filter tool with the Low option.

• By default, this tool will use multicore processors if available. The maximum number of cores that can be used is four.

  To use fewer cores, use the Parallel Processing Factor environment setting.

• If the Extent environment is specified and the lower left corner of the output extent does not match any cell corner of the input raster, a shift of the cell alignment of the input raster will occur during processing 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 for the Snap Raster environment.

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

Parameters

Dialog

Label	Explanation	Data Type
Input raster	The input surface raster.	Raster Layer
Output polyline features	The output contour polyline features.	Feature Class
Contour values	List of z-values for which to create contours.	Double

Python

ContourList(in_raster, out_polyline_features, contour_values)

Name	Explanation	Data 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"

# Execute ContourList
ContourList(inRaster, outContours, contourIntervalList)

Environments

Auto Commit, Cell Size, Cell Size Projection Method, Current Workspace, Default Output Z Value, Extent, Geographic Transformations, M Resolution, M Tolerance, Maintain Spatial Index, Output CONFIG Keyword, Output Coordinate System, Output has M values, Output has Z values, Output M Domain, Output XY Domain, Output Z Domain, Parallel Processing Factor, Scratch Workspace, Snap Raster, Z Resolution, Z Tolerance