topic Re: [ArcPy] GraudatedColorRenderer error: incorrect labels produced in Python Questions

[ArcPy] GraudatedColorRenderer error: incorrect labels produced

brusselsboy — Mon, 02 Jun 2025 11:37:35 GMT

Hi there, I was doing some ArcPy coding (ArcGIS Pro 3.4.2). I was applying GraduatedColorRenderer + Manual + 5 classes + customized colors and labels to a feature layer. Everything of the result was good except the labels, not what I expected from my code (below).

''' I want to apply the GraudatedColorRenderer to my feature layer using the manual classification method. I also want to use my own colors and labels for each class. However, the result show different labels and I cannot figure what the problem is. ''' import arcpy arcpy.env.overwriteOutput = True # Obtain the current project and map project = arcpy.mp.ArcGISProject("CURRENT") map = project.listMaps("Map")[0] # Obtain the feature layer layer = map.listLayers("Ottawa_Census")[0] # Use GraduatedColorsRenderer sym = layer.symbology sym.updateRenderer('GraduatedColorsRenderer') print('Renderer has been updated to GraudatedColorRenderer') # Set the classification field, method, and the number of classes sym.renderer.classificationField = "POP_2016" sym.renderer.classificationMethod = "Manual" sym.renderer.breakCount = 5 print('Classification field, method, and breakcount have been set.') # Customized settings manual_breaks = [500, 1000, 2000, 3000, 20000] manual_colors = [ {'RGB': [255, 190, 190, 100]}, {'RGB': [255, 127, 127, 100]}, {'RGB': [255, 0, 0, 100]}, {'RGB': [230, 0, 0, 100]}, {'RGB': [168, 0, 0, 100]} ] manual_labels = [ "0.0-500", "500-1000", "1000-2000", "2000-3000", "3000-20000" ] print('Breaks, colors, and labels have been set.') # Apply the above settings for i, brk in enumerate(sym.renderer.classBreaks): brk.label = manual_labels[i] brk.symbol.color = manual_colors[i] brk.upperBound = manual_breaks[i] layer.symbology = sym project.save() pdf = arcpy.mp.CreateExportFormat('PDF', r'D:\Learning ArcPy\challenge\layout_export.pdf') project.listLayouts()[0].export(pdf) print("Task done!")

Re: [ArcPy] GraudatedColorRenderer error: incorrect labels produced

TonyAlmeida — Mon, 02 Jun 2025 18:58:21 GMT

This works for me, the code applies two-step process that first applies default symbology before modifying breaks and applies symbology after setting breakCount.

# Step 1: First apply default graduated colors sym = lyr.symbology sym.updateRenderer('GraduatedColorsRenderer') sym.renderer.classificationField = "Acres" sym.renderer.breakCount = 5 lyr.symbology = sym # This initializes the breaks # Step 2: Now modify the breaks sym = lyr.symbology # Get fresh symbology # Configure breaks breaks = [ (100, "0-100", [255, 190, 190, 100]), (200, "100-200", [255, 127, 127, 100]), (300, "200-300", [255, 0, 0, 100]), (400, "300-400", [230, 0, 0, 100]), (500, "400-500", [168, 0, 0, 100]) ] # Apply breaks for i in range(5): sym.renderer.classBreaks[i].upperBound = breaks[i][0] sym.renderer.classBreaks[i].label = breaks[i][1] sym.renderer.classBreaks[i].symbol.color = {'RGB': breaks[i][2]} sym.renderer.classBreaks[i].lowerBound = 0 if i == 0 else breaks[i-1][0] # Step 3: Final apply lyr.symbology = sym print("DONE: Graduated colors applied with 5 manual breaks")

Re: [ArcPy] GraudatedColorRenderer error: incorrect labels produced

brusselsboy — Wed, 04 Jun 2025 14:33:22 GMT

Thank you @TonyAlmeida so much. I have tested your code with my dataset. It worked perfectly. I don't consider using the lowerBound property, as it isn't explicitly listed on the ClassBreak class documentation page. I think you idea of first applying the GraduatedColorRenderer and then changing it is the key to the solution.

Re: [ArcPy] GraudatedColorRenderer error: incorrect labels produced

brusselsboy — Wed, 04 Jun 2025 14:32:58 GMT

import arcpy arcpy.env.overwriteOutput = True project = arcpy.mp.ArcGISProject("CURRENT") map = project.listMaps("Map")[0] lyr = map.listLayers("Ottawa_Census")[0] # Step 1: First apply default graduated colors sym = lyr.symbology sym.updateRenderer('GraduatedColorsRenderer') sym.renderer.classificationField = "POP_2016" sym.renderer.breakCount = 5 lyr.symbology = sym # This initializes the breaks # Step 2: Now modify the breaks sym = lyr.symbology # Get fresh symbology #print(sym.renderer.breakCount) # Configure breaks breaks = [ # I prefer lists to sets but both work. [500, "0-500", [255, 190, 190, 100]], [1000, "501-1000", [255, 127, 127, 100]], [2000, "1001-2000", [255, 0, 0, 100]], [3000, "2001-3000", [230, 0, 0, 100]], [2000, "3001-20000", [168, 0, 0, 100]] ] # Apply breaks for i in range(5): sym.renderer.classBreaks[i].upperBound = breaks[i][0] sym.renderer.classBreaks[i].label = breaks[i][1] sym.renderer.classBreaks[i].symbol.color = {'RGB': breaks[i][2]} # Step 3: Final apply lyr.symbology = sym print("DONE: Graduated colors applied with 5 manual breaks") project.save() pdf = arcpy.mp.CreateExportFormat('PDF', r'D:\Learning ArcPy\challenge\layout_export.pdf') project.listLayouts()[0].export(pdf) print("Task done!")