topic Re: Best Practices for selecting a feature from a feature class that was just created. in Python Questions

Best Practices for selecting a feature from a feature class that was just created.

ZacharyKasson — Fri, 16 May 2025 19:01:49 GMT

I'm wondering what's the best practice is 4 selecting features of a feature class that was just created in the same tool.

This code works perfectly fine when I am running it in a notebook in pro. I get the expected amount of features in my output feature class. I presume this works because it adds the feature to my map and is able to select the desired features.

arcpy.conversion.ExportFeatures( in_features=in_features, out_features= output_path, where_clause="Status = 'Confirmed'", use_field_alias_as_name="NOT_USE_ALIAS", field_mapping= field_mapping ) arcpy.AddMessage('Exported routes') arcpy.management.SelectLayerByLocation( in_layer= f"{output_file_name}", overlap_type="INTERSECT", select_features=f"{feature1}", search_distance="5 Meters", selection_type="NEW_SELECTION", invert_spatial_relationship="NOT_INVERT" ) arcpy.management.DeleteRows(output_file_name) arcpy.management.SelectLayerByLocation( in_layer= f"{output_file_name}", overlap_type="INTERSECT", select_features=f"{feature2}", search_distance="5 Meters", selection_type="NEW_SELECTION", invert_spatial_relationship="INVERT" ) arcpy.management.DeleteRows(output_file_name)

but when I turn this into a tool the output feature class has 0 features in it. I'm guessing this does not work because it cannot select features of a feature class that is not in my map.

I have tried to add the newly created feature class to my map using a couple different methods:

These return a layer object but the layer is not added to my map.

I guess the overall question is: what is the best way to approach making a selection from a feature class that has just been created?

Re: Best Practices for selecting a feature from a feature class that was just created.

TonyAlmeida — Fri, 16 May 2025 21:13:00 GMT

Use arcpy.MakeFeatureLayer_managment prior to SelectLayerByLocation

Something like this,

# Create selection feature layer (your exact format) Sel_Point = arcpy.MakeFeatureLayer_management( selection_feature, "point_layer", "\"FID\"={}".format(str(fid_value)) #or OID # Perform selection arcpy.management.SelectLayerByLocation( in_layer=output_file_name, overlap_type="INTERSECT", select_features=Sel_Point, # Using the variable you created search_distance="5 Meters", selection_type="NEW_SELECTION", invert_spatial_relationship="NOT_INVERT" )

Re: Best Practices for selecting a feature from a feature class that was just created.

ZacharyKasson — Mon, 19 May 2025 17:41:23 GMT

I noticed that you assigned the result of arcpy.MakeFeatureLayer_management to a variable named Sel_Point.

Is it considered best practice to store the output of a tool in a variable like this? Does assigning it to a variable improve the tool’s performance or is it mainly for readability and convenience?

Re: Best Practices for selecting a feature from a feature class that was just created.

TonyAlmeida — Mon, 19 May 2025 18:03:19 GMT

Yes, it is best practice. It would be more for readability than anything, in my opinion. it does nothing for performance that I am aware of.

Re: Best Practices for selecting a feature from a feature class that was just created.

GISDepartmentMFM — Tue, 20 May 2025 19:18:06 GMT

it also lets you add it to the map

map.addLayer(Sel_Point.getOutput(0))