topic Re: What is arcpy.cim? in ArcGIS Pro Questions

What is arcpy.cim?

GraemeBrowning — Thu, 10 Oct 2019 22:04:00 GMT

In the help for ArcGIS Pro 2.4's Python CIM access there is "Example 3: Modify layer symbology" which has this code:

    # Reference a project, map, and layer using arcpy.mp
    p = arcpy.mp.ArcGISProject('current')
    m = p.listMaps('Trail Routes')[0]
    lyr = m.listLayers('Loops')[0]

    # Return the layer's CIM definition
    cim_lyr = lyr.getDefinition('V2')

    # Modify the color, width and dash template for the SolidStroke layer
    symLvl1 = cim_lyr.Renderer.Symbol.Symbol.SymbolLayers[0]
    symLvl1.Color.Values = [250, 250, 40, 50]
    symLvl1.Width = 8
    ef1 = symLvl1.Effects[0]    #Note, deeper indentation
    ef1.DashTemplate = [20, 30]

    # Modify the color/transparency for the SolidFill layer
    symLvl2 = cim_lyr.Renderer.Symbol.Symbol.SymbolLayers[1]
    symLvl2.Color.Values = [140, 70, 20, 20]

    # Push the changes back to the layer object
    lyr.setDefinition(cim_lyr)

I think the documentation was written before finalization of ArcGIS Pro 2.4, where this functionality was introduced for the first time, because it seems to contain capitalization errors, and is missing a key line that I picked up by watching a YouTube video from Esri's 2019 Developer Summit.

This code should work correctly:

    # Reference a project, map, and layer using arcpy.mp
    p = arcpy.mp.ArcGISProject('current')
    m = p.listMaps('Trail Routes')[0]
    lyr = m.listLayers('Loops')[0]

    # Return the layer's CIM definition
    cim_lyr = lyr.getDefinition('V2')

    # Modify the color, width and dash template for the SolidStroke layer
    symLvl1 = cim_lyr.renderer.symbol.symbol.symbolLayers[0]
    symLvl1.color.values = [250, 250, 40, 50]
    symLvl1.width = 8
    symLvl1.effects = [arcpy.cim.CIMGeometricEffectDashes()]
    ef1 = symLvl1.effects[0]    #Note, deeper indentation
    ef1.dashTemplate = [20, 30]

    # Modify the color/transparency for the SolidFill layer
    symLvl2 = cim_lyr.renderer.symbol.symbol.symbolLayers[1]
    symLvl2.color.values = [140, 70, 20, 20]

    # Push the changes back to the layer object
    lyr.setDefinition(cim_lyr)

The missing line (which I added in the above) is:

symLvl1.effects = [arcpy.cim.CIMGeometricEffectDashes()]

Is `arcpy.cim` an undocumented ArcPy module, function or class, and to learn about it, is reading the ArcGIS.Core.CIM Namespace .NET SDK API Reference the only way?

I have reported what I believe to be the documentation error using the link at the bottom of that help page. I have also asked this question on another site as symbology - What is arcpy.cim? - Geographic Information Systems Stack Exchange.

Re: What is arcpy.cim?

DanPatterson_Retired — Thu, 10 Oct 2019 22:26:23 GMT

Python CIM access—ArcPy | ArcGIS Desktop

and in your install path for exploration

C:\YourInstallFolder\Resources\ArcPy\arcpy\cim

Re: What is arcpy.cim?

JeffBarrette — Thu, 10 Oct 2019 22:40:15 GMT

Thank you for reporting this! You are correct; late in 2.4 development we changed the CamelBack format of the object members to be consistent with the managed API. I failed to update example 3 and you caught it. The script was corrected and will appear in the next help publication.

The missing line that you added is NOT required if the symbol already has a dashed effect. What the line did essentially was generate the effect. This is something you need to be very careful about doing. The Developer Summit plenary video does show the line you added. That particular example is a simple use case but due to the complexity of object creation where new objects have dependencies on addition objects, it is easy to create objects that may fail in the application.

The arcpy.cim module is necessary for CIM support but we intentionally did not document it. We hope that with future builds we will provide helper functions that will make it easier and more reliable to create new objects.

Thanks again,

Jeff

Re: What is arcpy.cim?

LauraTateosian — Mon, 05 Oct 2020 15:53:13 GMT

Hi Jeff,

It's been about a year since you wrote the note above. Would you say that at this point the helper functions that you anticipated have been released? Or are they still a work in progress?

Or would you say the trajectory of fine-graded access to symbology changed so that arcpy users are more likely to need to learn the nuances of CIM?

Thanks in advance for your insights.

Laura

Re: What is arcpy.cim?

JeffBarrette — Tue, 06 Oct 2020 14:49:28 GMT

Hello Laura,

Yes, at 2.5 we introduced this. THere is a new section in the Python CIM Access topic titled Creating CIM Objects.

Python CIM access—ArcGIS Pro | Documentation

Jeff