ArcMap

GA Layer To Contour

Available with Geostatistical Analyst license.

Summary

Creates a feature class of contours from a geostatistical layer. The output feature class can be either a line feature class of contour lines or a polygon feature class of filled contours.

Usage

  • For data formats that support Null values, such as file geodatabase feature classes, a Null value will be used to indicate that a prediction could not be made for that location or that the value should be ignored when used as input. For data formats that do not support Null values, such as shapefiles, the value of -1.7976931348623158e+308 is used (this is the negative of the C++ defined constant DBL_MAX) to indicate that a prediction could not be made for that location.

  • The output polygon or polyline features will contain slightly different geometry depending on the number of CPU cores of your machine. This is due to a different number of tiles that will be used in the contour algorithm (more cores allow for more tiling and, hence, more refined contours in the output).

Syntax

arcpy.ga.GALayerToContour(in_geostat_layer, contour_type, out_feature_class, {contour_quality}, {classification_type}, {classes_count}, {classes_breaks})
ParameterExplanationData Type
in_geostat_layer

The geostatistical layer to be analyzed.

Geostatistical Layer
contour_type

Type of contour to represent the geostatistical layer.

  • CONTOUR — The contour or isoline representation of the geostatistical layer. Displays the lines in either draft or presentation quality.
  • FILLED_CONTOUR —The polygon representation of the geostatistical layer. It assumes for the graphical display that the values between contour lines are the same for all locations within the polygon. Displays the lines in either draft or presentation quality.
  • SAME_AS_LAYER —Use the current renderer of the input geostatistical layer. If the geostatistical layer is not rendered as either contour or filled contour, this option will created filled contours. Similarly, if the geostatistical layer is rendered as both contour and filled contour, this option will create filled contours.
String
out_feature_class

The output feature class will either be a polyline or a polygon, depending on the selected contour type.

Feature Class
contour_quality
(Optional)

Determines the smoothness of contour line representation.

  • DRAFT — The default Draft quality presents a generalized version of isolines for faster display.
  • PRESENTATION —The Presentation option ensures more detailed isolines for the output feature class.
String
classification_type
(Optional)

Specifies how the contour breaks will be calculated.

  • GEOMETRIC_INTERVAL —Contour breaks are calculated based on geometric intervals.
  • EQUAL_INTERVAL —Contour breaks are calculated based on equal intervals.
  • QUANTILE —Contour breaks are calculated from quantiles of the input data.
  • MANUAL —Specify your own break values.
String
classes_count
(Optional)

Specify the number of classes in the output feature class.

If contour_type is set to output filled contour polygons, the number of polygons created will equal the value specified in this parameter. If it is set to output contour polylines, the number of polylines will be one less than the value specified in this parameter (because N class intervals define N-1 contour break values).

This parameter does not apply if the classification_type is set to Manual.

Long
classes_breaks
[classes_breaks,...]
(Optional)

The list of break values if the classification_type is set to Manual. The values should be passed as a list, and the values can be in any order.

  • For contour output, these are the values of the contour lines.
  • For filled contour, these are the upper limits of each class interval. Note that if the largest break value is less than the maximum of the geostatistical layer, the output feature class will not fill up the entire rectangular extent; all locations with predicted values above the largest break will not receive filled contours.
Double

Code sample

GALayerToContour interactive window example

Export a geostatistical layer to a contour feature class.

import arcpy
from arcpy import env
env.workspace = "C:/gapyexamples/data"
arcpy.GALayerToContour_ga("kriging.lyr", "Contour", "krig_contour",
                          "Presentation", "GEOMETRIC_INTERVAL", 10, "")
GALayerToContour script example

Export a geostatistical layer to a contour feature class.

# Name: GALayerToContour_Example_02.py
# Description: Exports a geostatistical layer to filled contours with
#              class breaks at 100, 500 and 2000.
# Requirements: Geostatistical Analyst Extension

# Import system modules
import arcpy

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

# Set local variables
in_geostat_layer = "kriging.lyr"
contour_type = "Filled_contour"
out_feature_class = "C:/gapyexamples/output/krig_filled_contour.shp"
contour_quality = "Presentation"
classification_type = "Manual"
classes_count = ""
classes_breaks = [100, 500, 2000]

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

# Execute GALayerToContour
arcpy.GALayerToContour_ga(in_geostat_layer, contour_type, out_feature_class,
                          contour_quality, classification_type, classes_count,
                          classes_breaks)

Environments

Licensing information

  • Basic: Requires Geostatistical Analyst
  • Standard: Requires Geostatistical Analyst
  • Advanced: Requires Geostatistical Analyst

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