GraduatedColorsRenderer

Summary

The GraduatedColorsRenderer class represents the graduated color renderer definition that shows qualitative differences in feature values using a range of color.

Discussion

The properties behave in a similar manner to the options exposed in the application. For example, changing the number of classes will automatically adjust the break values and their labels. If you change upperBound of a ClassBreak, the classificationMethod automatically changes to ManualInterval. You also need to manually update the labels and/or descriptions accordingly.

Properties

Property	Explanation	Data Type
breakCount (Read and Write)	An integer that represents the number of classes to be used with the current classification method.	Integer
classBreaks (Read and Write)	A list of ClassBreak objects that provides access to individual properties such as label and description as well as individual symbol objects.	List
classificationField (Read and Write)	A string that represents a valid field name used for the layer's classification method.	String
classificationMethod (Read and Write)	A string that represents a valid classification method. The valid values are as follows: DefinedInterval—Defined Interval EqualInterval—Equal Interval GeometricInterval—Geometric Interval ManualInterval—Manual Interval NaturalBreaks—Natural Breaks (Jenks) Quantile—Quantile StandardDeviation—Standard Deviation	String
colorRamp (Read and Write)	Provides access to the ColorRamp object.	ColorRamp
deviationInterval (Read and Write)	A double that represents a valid deviation interval that is only available if classificationMethod is set to StandardDeviation. Valid values are 1.0, 0.5, 0.333, and 0.25. These are the same options available in the application.	Double
intervalSize (Read and Write)	A double that represents an interval size that is only available if classificationMethod is set to DefinedInterval.	Double
lowerBound (Read and Write)	A double that represents the minimum value of the symbolized classificationField to be displayed. Note: The value of the lowerBound should only be set to a value within the range of the first class break, otherwise it will fail. The maximum value gets modified in the last class break by changing the upperBound property.	Double
normalizationField (Read and Write)	A string that represents a valid layer field name that is used for normalization.	String
normalizationType (Read and Write)	A specific string that represents a valid normalization key word. For example, to clear the normalization, try gradColors.renderer.nomalizationType = "<None>". <None>—No normalization <percentage of total>—Percentage of total <log>—Log	String
type (Read Only)	Returns a string that represents the renderer type.	String

Code sample

GraduatedColorsRenderer example 1

The following script first tests if the layer's symbology supports a renderer property and then confirms if the renderer is a SimpleSymbolRenderer. Next is changes the renderer to aGraduatedColorsRenderer and it changes the classificationField and breakCount. Finally, it changes ColorRamp to a color ramp named Cyan to Purple.

import arcpy, os, sys

relpath = os.path.dirname(sys.argv[0])

p = arcpy.mp.ArcGISProject(relpath + r'\\GraduatedColors.aprx')
m = p.listMaps('Layers')[0]
l = m.listLayers('State*')[0]
sym = l.symbology

if hasattr(sym, 'renderer'):
  if sym.renderer.type == 'SimpleRenderer':
    sym.updateRenderer('GraduatedColorsRenderer')
    sym.renderer.classificationField = 'Shape_Area'
    sym.renderer.breakCount = 10
    sym.renderer.colorRamp = p.listColorRamps('Cyan to Purple')[0]

    l.symbology = sym

p.saveACopy(relpath + r'\\SavedOutput.aprx')

GraduatedColorsRenderer example 2

The following script modifies the symbology of a polygon layer that uses a graduate color renderer. It sets the classificationField and breakCount and iterates through each class break and modifies the upperBound, label, description, and symbol properties such as color, outlineColor, and size. The labels for each break are formatted to include thousands separators. The fill color graduates from red to blue, and the outline color goes from blue to red and increases in size with each break.

# -*- coding: utf-8 -*-
import arcpy, os, sys, locale

relpath = os.path.dirname(sys.argv[0])

p = arcpy.mp.ArcGISProject(relpath + r"\\GraduatedColors.aprx")
m = p.listMaps("Layers")[0]
l = m.listLayers("Natural*")[0]

sym = l.symbology
sym.renderer.classificationField = "Shape_Area"
sym.renderer.breakCount = 7

breakVal = 100000000000
cv = 0
lw = 1
for brk in sym.renderer.classBreaks:
  brk.upperBound = breakVal
  brk.label = "\u2264" + str(locale.format("%d", breakVal, grouping=True))
  brk.description = "Description " + str(cv)
  brk.symbol.color = {'HSV' : [cv, 100, 100, 100]}
  brk.symbol.outlineColor = {'HSV' : [240-cv, 100, 100, 100]}
  brk.symbol.size = lw

  breakVal +=100000000000
  cv += 40
  lw += 0.5
l.symbology = sym

p.saveACopy(relpath + r'\\SavedOutput.aprx')

GraduatedColorsRenderer example 3

The following script modifies the lowerBound and upperBound property values for the renderer's symbolized classificationField. It also uses Python CIM access to display the out of range classificationField values using a default symbol that is automatically generated.

p = arcpy.mp.ArcGISProject('current')
m = p.listMaps('LowerBoundResult')[0]
l = m.listLayers()[0]
if hasattr(l.symbology, 'renderer'):
  if l.symbology.renderer.type == 'GraduatedColorsRenderer':
    sym = l.symbology
    #Set lowerBound set on Renderer
    sym.renderer.lowerBound = 5
    #Set upperBound set on upper ClassBreak
    sym.renderer.classBreaks[-1].upperBound = 96 
    l.symbology = sym

    #Show values out of range using Python CIM Access
    l_cim = l.getDefinition('V3')
    l_cim.renderer.useDefaultSymbol = True
    l_cim.renderer.defaultLabel = "Out of range"
    l.setDefinition(l_cim)