Issues with feature layers and python

ThomasCaruso — Sat, 11 Dec 2021 16:12:30 GMT

Hey folks,

Pretty new to GIS and scripting (in any language) and I'm trying to write a program that will, basically:

1) look at a point that represents an unverified well location

2) search for all centroids within a certain distance and select them

3) compare the last name of the well owner with the last name of all selected centroid owners

4) if there is a match between any, put "yes" in a "match" column

Here are the issues I'm having:

1) the arcpy.SelectLayerByLocation function requires a feature layer input. I added a line in my script that makes my centroid data into a feature layer, which actually creates a layer in my table of contents, and when I fix an error and try to run the script again, it stops almost immediately saying that the feature layer already exists. If I take it out of the script, then the feature layer is undefined for later. My supervisor (who has a good amount of GIS experience) says something is happening weirdly there and is unsure why.

2) lock issues. Every time I try to run it and it gets past the feature layer part, I get this error:

Runtime error Traceback (most recent call last): File "<string>", line 17, in <module> File "c:\program files (x86)\arcgis\desktop10.2\arcpy\arcpy\management.py", line 6618, in SelectLayerByLocation raise e ExecuteError: ERROR 999999: Error executing function. Cannot acquire a lock. Cannot acquire a lock. Item not found in this collection. Failed to execute (SelectLayerByLocation).

Can anyone point me in the right direction here?

Here is the code I've written

import arcpy
# define a workspace
arcpy.env.workspace = r"C:\Users\tmc18\Desktop\comp_orps\NYS_Wells.gdb"
# Define input files
orps = r"C:\Users\tmc18\Desktop\comp_orps\centroids\madirps_point1.shp"
wells = r"C:\Users\tmc18\Desktop\comp_orps\NYS_Wells.gdb\Madison_DEC_Well_Logs_3_14_14_MASTER_COPY1"
arcpy.MakeFeatureLayer_management(orps, "orpsFL")
# Create well update cursor, will compare the "owner_last" field value of the well used to select nearby centroids to the "owner_last"
# field of centroid data. 
with arcpy.da.UpdateCursor(wells, ["match", "owner_last"]) as cursor:
        for row in cursor:
                # select by location
                arcpy.SelectLayerByLocation_management("orpsFL", "WITHIN_A_DISTANCE", wells, "0.5 kilometers", "new_selection")
                # create orps name cursor
                orps_match = arcpy.da.SearchCursor("orpsFL", ["owner_last"])
                # if the uppercase string value of the well owner's last name != the centroid, then the orps_match cursor will move to the next
                # centroid name and try that one.
                if str([row[1] for row in cursor]).upper != str([row[0] for row in orps_match]).upper:
                        orps_match.next
                        
                # but if they do match, we get a "yes" in the match column
                else:
                        row[0] = "YES"
                        cursor.updateRow(row)
                        continue

Thanks in advance!

Re: Issues with feature layers and python

JakeSkinner — Wed, 31 Dec 2014 20:37:08 GMT

Hi Thomas,

You can add the following line below you 'import arcpy' statement to overwrite any output layers, in this case your Feature Layer.

arcpy.env.overwriteOutput = 1

See if that will help with the lock issue you are receiving as well.

Re: Issues with feature layers and python

ThomasCaruso — Tue, 06 Jan 2015 16:44:02 GMT

Hi Jake,

Thank you, that solved that little hangup. The lock issue was my own fault, it was because I made my cursor an update cursor which locked the table I was trying to select features from. Thanks again for your help!

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Issues with feature layers and python

Re: Issues with feature layers and python

Re: Issues with feature layers and python