NoneType object is not iterable

JacobEngelman

Hello, 

I have a script to perform a simple everyday task I have to do at work that had been working well (for years) until recently. The script looks through a GDB to find unprocessed point FCs and turns them into smooth lines. However, recently I have been receiving the following error:

Traceback (most recent call last):
File "E:\MapFiles\Trails\TrailConditionMonitoring\OSMP_TrailAlignData\PointsToLineArcPro.py", line 9, in <module>
gpsPointList = list((arcpy.ListFeatureClasses(feature_type=pnt)))
TypeError: 'NoneType' object is not iterable

I'm unsure why the script worked for so long then all of a sudden threw this error. Why could I iterate through the list of feature classes before, but not now? Any help would be appreciated! The script is posted below.

# A script that looks through a GDB to find point fcs that need to be processed into smooth lines and processes them
import arcpy

# set workspace
wksp = arcpy.env.workspace = arcpy.GetParameterAsText(0)

# define variables for point and line features
pnt = "Point"
gpsPointList = list((arcpy.ListFeatureClasses(feature_type=pnt)))
print(gpsPointList)
line = "Line"
existingLines = list((arcpy.ListFeatureClasses(feature_type=line)))
print(existingLines)

# set up loop to add smooth text to the end of the point feature classes
smooth = "Smooth"
strPoint = ""
checkPoints = []
for points in gpsPointList:
strPoint = points + smooth
checkPoints.append(strPoint)

print(checkPoints)

# Set up list variables to store already processed and unprocessed point features
processedPoints = []
unprocessedPoints = []

# set up to iterate through the point feature classes to find duplicates(processed points)
unPointStr = ""
for pointfc in checkPoints:
if pointfc in existingLines:
processedPoints.append(pointfc)
else:
unPointStr = pointfc[:-6]
unprocessedPoints.append(unPointStr)

# Use exception handling to stop code if no point fcs need to be processed
if len(unprocessedPoints) == 0:
raise Exception("All point feature classes have been processed.")
else:
print(unprocessedPoints, "\n", len(unprocessedPoints), "point feature classes ready to process.")

# Iterate through unprocessed point fcs to turn them into smooth lines
sr = arcpy.SpatialReference(6429) # Code for NAD1983 (2011) StatePlane Colorado North FIPS
project = ""
ptsToLine = ""
for unpro in unprocessedPoints:
try:
# Project points to match other city data
project = unpro + "project"
arcpy.Project_management(unpro, project, sr)
print(project)

# Turn points into line
ptsToLine = project + "Line"
linefield = "RID"
arcpy.PointsToLine_management(project, ptsToLine, linefield)
print(ptsToLine)

# Smooth the line for a nice finished product
smoothLine = unpro + "Smooth"
alg = "PAEK" # algorithm for smoothing
tolerance = 5 # tolerance for smoothing
arcpy.SmoothLine_cartography(ptsToLine, smoothLine, alg, tolerance)
print(smoothLine + " Processed")

# delete intermediate data
arcpy.Delete_management(ptsToLine)
arcpy.Delete_management(project)

# use iteration to create a trail name for a new field
trail = smoothLine[:-12]
trail2 = ""

for i in range(len(trail)):
if (trail[i].isupper()):
trail2 += " "
trail2 += trail[i]
else:
trail2 += trail[i]
trailName = trail2[1:]
print(trailName)

# use cursor to add trail name field to smooth line fc
nameField = "TrailName"
arcpy.AddField_management(smoothLine, nameField, "TEXT")
print("Trail Name field added")

with arcpy.da.UpdateCursor(smoothLine, nameField) as cursor:
for row in cursor:
row[0] = trailName
cursor.updateRow(row)
print(trailName + " added")
del cursor, row

except:
print("Something went wrong check your unprocessed point list" + "\n" + unprocessedPoints)

print("Processing Complete")

 

Tonyalmeida

i would start with checking your workspace. Also, if you arcpy.ListFeatureClasses() returns none, might be an issue. Try this,

import arcpy

# set workspace
wksp = arcpy.env.workspace = arcpy.GetParameterAsText(0)
print(f"Workspace: {wksp}")

# define variables for point and line features
pnt = "Point"
gpsPointList = arcpy.ListFeatureClasses(feature_type=pnt)
print(f"GPS Point List: {gpsPointList}")

if gpsPointList is None:
    raise Exception("No point feature classes found in the workspace.")

gpsPointList = list(gpsPointList)
line = "Line"
existingLines = arcpy.ListFeatureClasses(feature_type=line)
print(f"Existing Lines: {existingLines}")

if existingLines is None:
    raise Exception("No line feature classes found in the workspace.")

existingLines = list(existingLines)