topic Feature layer legend label format with arcpy in ArcGIS Pro Questions

Feature layer legend label format with arcpy

ErzsikeTerezsi — Mon, 06 Jan 2025 16:03:00 GMT

How can I round to 2 decimal places the feature class legend label in arcgis pro with python code, if it is divided into 5 classes using natural break method? The value is rounded up with my code, but still 6 decimal places are displayed. How to do it from code, because it would be part of a pdf printer process and it would be very important that the symbol explanation is easy to read. I can only do this by manual adjustment (Advanced symbolgy options/Rounding).

original label: 0.234567 - 0.41277

rounded by script: 0.230000 - 0.410000

I would like this: 0.23 - 0.41

p = arcpy.mp.ArcGISProject('CURRENT')
m = p.listMaps('MAP')[0]
l = m.listLayers("NDVI_mean")[0]
sym = l.symbology

if sym.renderer.type == "GraduatedColorsRenderer":
if sym.renderer.classificationMethod == "NaturalBreaks":
breaks = sym.renderer.classBreaks
for tor in breaks:
rounded_break_values = round(float(tor.upperBound), 2)
tor.upperBound = rounded_break_values
l.symbology = sym

Re: Feature layer legend label format with arcpy

DanPatterson — Mon, 06 Jan 2025 16:26:14 GMT

a = 1.2345678 float(f"{round(a,2):.2f}") 1.23

might work unless the upperBound etc is handled after the number formatting

Re: Feature layer legend label format with arcpy

DuncanHornby — Tue, 07 Jan 2025 13:43:06 GMT

I personally have found trying to change the labels in symbols always a bit flaky through direct manipulation of arcpy classes, but may be that's just me...

Anyway an alternative method is to access the CIM object module for fine tuning layer properties, this includes symbology. As you say in your question you can easily change the decimal places through Advanced symbology options in the UI, so lets replicate that!

import arcpy # Get handle on layer in first map p = arcpy.mp.ArcGISProject('CURRENT') m = p.listMaps('MAP')[0] l = m.listLayers("fc_AreasMerged")[0] sym = l.symbology # Change rounding value using CIM lcim = l.getDefinition('V2') lcim.renderer.numberFormat.roundingValue = 2 l.setDefinition(lcim) # Update/refresh renderer sym = l.symbology sym.updateRenderer ('GraduatedColorsRenderer') l.symbology = sym

If you want to get into manipulating CIM, best bit advice I can give is get hold of the CIM viewer AddIn, this allows you to see the CIM for a layer selected in the Contents Pane. I couldn't live without it!

Re: Feature layer legend label format with arcpy

ErzsikeTerezsi — Wed, 08 Jan 2025 08:55:25 GMT

Thank you! It is work fine.