topic Re: Convert CIM Object to JSON string in Python Questions

Convert CIM Object to JSON string

Pukawai — Tue, 02 Dec 2025 15:43:49 GMT

I'm writing a script to generate a UniqueValueRenderer from scratch using

arcpy.cim.CreateCIMObjectFromClassName('CIMUniqueValueRenderer','V3')

Since this object contains a lot of other CIM objects, I have to make all those as well, but somewhere in there I'm missing something so when writing it into the layer definition, Pro will crash.

Is there a way I can take my newly created CIMUniqueValueRenderer object and convert it to a JSON string so I can see what it contains?

I found a reference to a function GetJSONForCIMObject in another post, but can find no such function in the ArcPy documentation.

Re: Convert CIM Object to JSON string

AlfredBaldenweck — Tue, 02 Dec 2025 16:07:24 GMT

Well, that's kind of the problem with CIM. Arcane and not well documented.

x = arcpy.cim.CreateCIMObjectFromClassName('CIMUniqueValueRenderer','V3') y = arcpy.cim.GetJSONForCIMObject(x, 'V3') print(y) ''' {"sampleSize": 10000, "visualVariables": [], "colorRamp": {"colorSpace": {"type": "CIMColorSpace"}, "type": "CIMColorRamp"}, "defaultSymbol": {"primitiveOverrides": [], "symbol": {"type": "CIMSymbol"}, "minScale": 0.0, "maxScale": 0.0, "scaleDependentSizeVariation": [], "minDistance": 0.0, "maxDistance": 0.0, "type": "CIMSymbolReference"}, "defaultSymbolPatch": "Default", "fields": [], "groups": [], "useDefaultSymbol": false, "valueExpressionInfo": {"returnType": "Default", "type": "CIMExpressionInfo"}, "polygonSymbolColorTarget": "Fill", "authoringInfo": {"type": "CIMUniqueValueRendererAuthoringInfo"}, "type": "CIMUniqueValueRenderer"} '''

Honestly I check out the CIM's github reference and then spend a lot of time using the intellisense in the Python Window in Pro to figure out what I can do. Honestly I hadn't heard of that function before today.

Re: Convert CIM Object to JSON string

Pukawai — Tue, 02 Dec 2025 17:40:14 GMT

Thank you for this! With some massaging of that output string I should be able to compare it to a .lyrx file and discover what's missing. Now, if only intellisense worked in notebooks....

Re: Convert CIM Object to JSON string

AlfredBaldenweck — Wed, 17 Dec 2025 20:10:11 GMT

There's a certain irony in how much I've revisited this page over the last two weeks to remind myself of how to get this information.

Hard agree on the notebook. Huge pain.