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I'm trying to update missing values in one .shp from another .shp. I'm using SelectLayerByLocation to identify the properties which lie within the boundaries of a suburb and then using a UpdateCursor to update the properties list with the suburbs. The code below doesn't iterate through the list correctly so all I get is the first value from the initial SearchCursor updating the properties list.

fc_P = propertyDataset
fc_S = suburbsDataset
LOCALITYList = []
query = '"LOCALITY" =\'\''
field_P = ["LOCALITY"]
field_S = ["ADMINAREA"]

arcpy.MakeFeatureLayer_management(fc_S,"Suburbs_layer")
arcpy.MakeFeatureLayer_management(fc_P,"Properties_layer", query)

arcpy.SelectLayerByLocation_management("Properties_Layer", "WITHIN", 
"Suburbs_Layer")

with arcpy.da.SearchCursor("Suburbs_layer",field_S) as Srow:
    for row in Srow:
        Suburb = Srow[0]



with arcpy.da.UpdateCursor("Properties_layer", field_P) as Ucursor:
    for Urow in Ucursor:
        Urow[0] = Suburb
        Ucursor.updateRow(Urow)

del Ucursor
del Srow

suburbs.shp attribute table properties.shp attribute table

  • You are not iterating over localitylist in the code you present (for locality in localitylist:) – BERA Apr 22 at 7:53
  • i was using the localitylist to get a count of properties updated later in the code. would it be best to append the list during the search cursor and then use that within the update cursor? – Brett Apr 22 at 7:57
  • Are you trying to update properties that does not have a suburb (ADMINAREA?)? A screenshot showing the attribute tables and maybe the map would help in understanding your question. – BERA Apr 22 at 8:04
  • thats exactly what i'm trying to do. the locality in the properties dataset is named adminarea in the suburbs dataset. some properties dont have localities/adminareas listed. – Brett Apr 22 at 8:20
  • when i run the code it grabs the result from the row 0 in the property .shp which is toowoomba city and uses that that to fill in the blanks. – Brett Apr 22 at 8:29
4

I think you should try using spatial join instead. That way you dont need to iterate Select Layer By Location and multiple cursors. The output can be written to in_memory so that it not saved to disk and the output is used to create a dictionary of objectids and their suburb.

Try code below, I have no data to try it on so you might get some errors:

import arcpy

propfc = 'Properties'
subfc = 'Suburbs'
propfc_suburbfield = 'LOCALITY'
subfc_suburbfield = 'ADMINAREA'

#Create feature layer of properties with LOCALITY shorter than 2 charachters
sql = "CHAR_LENGTH({0})<2".format(arcpy.AddFieldDelimiters(propfc, propfc_suburbfield))
arcpy.MakeFeatureLayer_management(in_features=propfc, out_layer='proplyr', where_clause=sql)

#Spatial join suburbs to properties layer
tempspatjoin = r'in_memory\spatjoin'
arcpy.SpatialJoin_analysis(target_features='proplyr', join_features=subfc, out_feature_class=tempspatjoin, join_type='KEEP_COMMON',\
                           match_option='WITHIN')

#Create a dictionary of property objectids and what suburb they are in
updatedictionary = {k:v for k,v in arcpy.da.SearchCursor(tempspatjoin,['TARGET_FID',subfc_suburbfield])}

#Update proplyr with suburbs from dictionary
with arcpy.da.UpdateCursor('proplyr',['OID@',propfc_suburbfield]) as cursor:
    for row in cursor:
        if row[0] in updatedictionary: #If this rows oid is in dictionary
            row[1] = updatedictionary[row[0]] #Update with suburb
            cursor.updateRow(row)

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