How to get/set label scale ranges (e.g. minScale) in ArcPy?

Question

For a layer object lyr, one can programmatically set the minScale in arcpy as such:

lyr.minScale = 150000

For a label, one can manually set the scale range within a dialog in ArcMap. In arcpy, is there a way to programmatically set the minScale for a layer's label in much the same way one can for the layer itself?

I see that it can be done through the JavaScript API, but I haven't yet found a way via arcpy. (I have ArcMap 10.1 SP1.)

Answer 1

Here's an example of using ArcObjects in Python to get at this information. I leave modifying the values and saving the MXD as an exercise to the reader:

import arcpy
from ESRICOMHelpers import *
esriSystem = GetESRIModule("esriSystem")
esriCarto = GetESRIModule("esriCarto")

def enumerate_feature_layers(map):
    uid = NewObj(esriSystem.UID, esriSystem.IUID)
    uid.value = "{E156D7E5-22AF-11D3-9F99-00C04F6BC78E}" # IGeoFeatureLayer
    enumLayer = map.Layers(uid, True)
    enumLayer.Reset()
    layer = enumLayer.Next()
    while layer:
        yield layer
        layer = enumLayer.Next()

def enumerate_label_classes(layer):
    labelClasses = CType(layer, esriCarto.IGeoFeatureLayer).AnnotationProperties
    for i in range(labelClasses.Count):
        labelClass, labelClassId = CType(labelClasses, esriCarto.IAnnotateLayerPropertiesCollection2).QueryItem(i)
        yield labelClass

def open_map_document(path):
    mxd = NewObj(esriCarto.MapDocument, esriCarto.IMapDocument)
    mxd.Open(path)
    return mxd

def print_label_classes(mxd_path):
    mxd = open_map_document(mxd_path)
    map = mxd.Map[0]
    layers = enumerate_feature_layers(map)
    for layer in layers:
        print layer.Name
        for labelClass in enumerate_label_classes(layer):
            print "\tname: {0}, minScale: {1}, maxScale: {2}".format(labelClass.Class, labelClass.AnnotationMinimumScale, labelClass.AnnotationMaximumScale)
    mxd.Close()

if __name__ == '__main__':
    mxd_path = r"path\to\map.mxd"
    print_label_classes(mxd_path)

Get comtypes here.

The ESRICOMHelpers module is here.

Also note that for 10.1 and up you need to fix automation.py in the comtypes site package.

Answer 2

I looked at the LabelClass (arcpy.mapping) properties, which is where I believe this would need to be exposed and there is no such property available there either.

Consequently, for this one I suspect your best option will be to submit an ArcGIS Idea.

There is a generic idea to Expose the ArcMap layer properties through ArcPy which may lead to it being added.

However, I think we will see this functionality sooner if a specific one is submitted. If you do that post a link to it into your Question so that future visitors can also vote for it.