ArcPy - Python script and list of features in FGDB

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04-01-2019 01:53 PM
DudleyHartel
New Contributor II

I'm trying to run a Python script to merge all polygon features in a single file geodatabase but my ListFeatureClasses function doesn't appear to be returning any FC names!

See attached with screen shots and code

import arcpy

import os

 

# This will be the list of polygon features to merge

listFC = []

 

# Set the workspace to state CoreLogic FGDB

arcpy.env.workspace = r"L:\SRS_Heirs_29Mar19\20190310_R8_HeirsProperty_AL_CoreLogicParcelsMods_SRS4952.gdb"

 

# Set output FGDB

outputFGDB = r"D:\Documents\ArcGIS\Projects\SRS4952_Heirs\SRS4952_Heirs.gdb"

 

# Set output FGDB and new merged FC

mergedFC = os.path.join(outputFGDB, "CL_AL_ParcelsArea")

 

# Get list of polygon feature classes in FGDB

listFC = arcpy.ListFeatureClasses(feature_type='Polygon')

 

# Now merge

print ("Starting merge now...")

arcpy.Merge_management(inputs=listFC, output=mergedFC)

 

print("Finished polygon merge...")

ListFeatureClasses is not returning any polygon feature classes (there are about 100 in the FGDB)

All polygon features have the same data schema

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curtvprice
MVP Esteemed Contributor

As Dan is desrcribing, ListFeatureClasses will only give you a list from the current workspace. If the structure is only one deep you can replace this:

# Get list of polygon feature classes in FGDB
listFC = arcpy.ListFeatureClasses(feature_type='Polygon')‍‍‍‍

with this

from arcpy import env
# Get list of polygon feature classes in FGDB
wk = env.workspace
fds = arcpy.ListDatasets()
listFC = []
for fd in fds:
    env.workspace = os.path.join(wk, fd)
    fcs = arcpy.ListFeatureClasses(feature_type='Polygon')
    listFC += fcs
env.workspace = wk‍‍‍‍‍‍‍‍‍‍

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6 Replies
DanPatterson_Retired
MVP Esteemed Contributor

have you got them into feature datasets, everything is a level down from the gdb

ListDatasets—ArcPy Functions | ArcGIS Desktop 

curtvprice
MVP Esteemed Contributor

As Dan is desrcribing, ListFeatureClasses will only give you a list from the current workspace. If the structure is only one deep you can replace this:

# Get list of polygon feature classes in FGDB
listFC = arcpy.ListFeatureClasses(feature_type='Polygon')‍‍‍‍

with this

from arcpy import env
# Get list of polygon feature classes in FGDB
wk = env.workspace
fds = arcpy.ListDatasets()
listFC = []
for fd in fds:
    env.workspace = os.path.join(wk, fd)
    fcs = arcpy.ListFeatureClasses(feature_type='Polygon')
    listFC += fcs
env.workspace = wk‍‍‍‍‍‍‍‍‍‍
DudleyHartel
New Contributor II

Curtis,

Thanks... I usually don't use datasets so wasn't familiar with that -

this was an inherited FGDB

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JoshuaBixby
MVP Esteemed Contributor

Another approach, which I would argue is more Pythonic, would be to use Walk—Help | ArcGIS Desktop :

import arcpy
import os

# Set workspaces and output(s)
inputFGDB = r"L:\SRS_Heirs_29Mar19\20190310_R8_HeirsProperty_AL_CoreLogicParcelsMods_SRS4952.gdb"
outputFGDB =  r"D:\Documents\ArcGIS\Projects\SRS4952_Heirs\SRS4952_Heirs.gdb"
mergedFC = os.path.join(outputFGDB, "CL_AL_ParcelsArea")

# Get list of polygon feature classes in FGDB
walk = arcpy.da.Walk(inputFGDB, datatype="FeatureClass")
listFC = [
    os.path.join(root, feature_class)
    for root, data_sets, feature_classes in walk
    for feature_class in feature_classes
]

# Now merge
print ("Starting merge now...")
arcpy.Merge_management(inputs=listFC, output=mergedFC)
print("Finished polygon merge...")
DudleyHartel
New Contributor II

Thank you

Yes I've seen that  function and actually tested it; much cleaner

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DudleyHartel
New Contributor II

Thanks for the replies, I've implemented Curtis' and filing the walk() function for later use.  Final code as follows for others interested:

# 02Apr19
# Heirs Property Processing Script - SRS4952
# Dudley R. Hartel
# 747 Maxine Dr
# Baton Rouge, LA 70808
# 706-988-3916 cell
# arborist.dudley.hartel@gmail.com
# Python 2.7 (ArcMap) and 3 (ArcGIS Pro) should both work
# GeoNet Assistance: Curtis Price, Joshua Bixby, Dan Patterson [01Apr19]

# Finds all polygons in a FGDB (e.g. CoreLocic state level FGDB) and merges them into a new feature class.
#    Takes county level features and merges into a single feature for the state
import arcpy
import os
from arcpy import env
# For each state to be processed...
#     1) workspace - change the 2 character state code
#     2) outputFGDB - verify the output location
#     3) mergedFC - change the 2 character state code
# Set the workspace to state CoreLogic FGDB
env.workspace = r"L:\SRS_Heirs_29Mar19\20190310_R8_HeirsProperty_GA_CoreLogicParcelsMods_SRS4952.gdb"
# Set output FGDB
outputFGDB = r"L:\SRS_Heirs_29Mar19\SRS4952_StateHeirsJoins.gdb"
# Set output FGDB and new merged FC
mergedFC = os.path.join(outputFGDB, "CL_GA_AreaParcels")
# This will be the list of polygon features to merge
listFC = []
# This will be the list of datasets in the FGDB 
listDS = []
# Get list of polygon feature classes in FGDB
currentWS = env.workspace
print ("\n \n \n" + "Getting polygon features now...")
# Each county is in a dataset with a point and polygon feature
# Get each dataset
listDS = arcpy.ListDatasets()
# Now look into each datset and find the polygon features
for fds in listDS:
    env.workspace = os.path.join(currentWS, fds)
    fcs = arcpy.ListFeatureClasses(feature_type='Polygon')
    listFC += fcs
env.workspace = currentWS
# Now merge
print("\n{}".format("Starting merge now...")) 
arcpy.Merge_management(inputs=listFC, output=mergedFC)
 print("\n{}".format("Finished polygon merge..."))
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