Last year I got assistance from StackExchange to write a Python script for ArcGIS 10.0 which loops through SelectLayerByLocation with buffer until it returns no new rows. Then it uses the selection for further processes.
We've just upgraded to ArcGIS 10.2.1 and I've discovered that the script no longer works :(
I can see in the Python window that the SelectLayerByLocation is running and the count increases, but the process stalls as soon as no new rows are returned. For example with the dummy data below, I get ...Row Count = 16.... ...Row Count = 18... ...Row Count = 18... The selected points are highlighted on screen, but the process hangs at that point. The script completes if the SelectByLocation detects no other sites within the distance (inDis2) of the selected site (fcFarmInterest), so I suspect the loop is the problem.
## Title: Autozone
## Function: Expanding selection of sites from a given site.
## Version: ArcGIS 10.0
## Author: Liam Mason, with assistance from dklassen @ GIS StackExchange
## Date: 5 August 2014
#Import ArcPy site package
import arcpy
# Overwrite files
arcpy.env.overwriteOutput = True
# Parameters
# Workspace setting
workSpace = r"C:\GIS\Autozone"
# Site ID as string
inSite = 'FS0501'
# Distance as string
inDis = '800'
# Name of farm data feature layer
farmData = "farms"
# Location of clipping shape shapefile
clipShape = "ClippingShape"
# Location for buffer to be saved into
outBuffer = r"C:\GIS\Autozone\Outputs\buffer.shp"
# Add meters to distance value
inDis1 = inDis + " meters"
# Convert distance value into integer, multiply by two, then remove a single unit. Convert back to string and add meters.
inDis2 = str((int(inDis)*2)-1) + " meters"
# Where query, adding inSite string as criteria.
where = '"Site_No" = ' + "'%s'" %inSite
# Set the workspace environment setting
arcpy.env.workspace = workSpace
try:
# Make a feature layer with all the farms
fcFarmsAll = farmData
#Select only marine farms, create output, then clear selection.
fcFarmsMarine = arcpy.SelectLayerByLocation_management(fcFarmsAll,"WITHIN", clipShape)
fcFarmsMarineOut = arcpy.CopyFeatures_management(fcFarmsMarine,r"\Working\marineFarms.shp")
arcpy.SelectLayerByAttribute_management(fcFarmsAll,"CLEAR_SELECTION")
# Make a feature layer with all the marine farms
fcFarms = arcpy.MakeFeatureLayer_management(r"\Working\marineFarms.shp", "MarineFarms")
#Select site of interest and create shapefile
fcFarmInterest = arcpy.Select_analysis (fcFarms, r"\Working\farms_Select.shp", where)
#Apply a selection to farms layer
fcFarms1 = arcpy.SelectLayerByLocation_management(fcFarms,"WITHIN_A_DISTANCE", fcFarmInterest, inDis2)
#Apply a further selection to farms layer
fcFarms2 = arcpy.SelectLayerByLocation_management(fcFarms1,"WITHIN_A_DISTANCE", fcFarms1, inDis2, "ADD_TO_SELECTION")
#Count selection
initial_getCount = int(arcpy.GetCount_management(fcFarms2).getOutput(0))
#Add one to selection count
getCount = initial_getCount + 1
#Loop through selection
while getCount > initial_getCount:
fcFarms3 = arcpy.SelectLayerByLocation_management(fcFarms,"WITHIN_A_DISTANCE", fcFarms2, inDis2, "ADD_TO_SELECTION")
initial_getCount = getCount
getCount = int(arcpy.GetCount_management(fcFarms3).getOutput(0))
#Buffer selection
arcpy.Buffer_analysis(fcFarms3,r"\Working\farms_buffer.shp", inDis1,"FULL","ROUND","ALL")
#Clip buffer
arcpy.Clip_analysis(r"\Working\farms_buffer.shp",clipShape,r"\Working\buffer_clip.shp")
#Break clipped buffer into multiparts
arcpy.MultipartToSinglepart_management(r"\Working\buffer_clip.shp",r"\Working\buffer_multi.shp")
#Make a feature layer for multipart buffer
fcBuffer = arcpy.MakeFeatureLayer_management(r"\Working\buffer_multi.shp","BufferTemp")
#Select buffer part with site of interest
fcBufferSelect = arcpy.SelectLayerByLocation_management(fcBuffer,"INTERSECT", fcFarmInterest)
#Export buffer to file, reselect sites within this buffer
fcBufferSites = arcpy.CopyFeatures_management(fcBufferSelect, r"\Working\buffer_sites.shp")
fcBufferSites1 = arcpy.SelectLayerByLocation_management(fcFarms,"INTERSECT", fcBufferSites)
#Buffer new selection, clip, break into multiparts, select and extract buffer part with sites
arcpy.Buffer_analysis(fcBufferSites1,r"\Working\farms_buffer1.shp", inDis1,"FULL","ROUND","ALL")
arcpy.Clip_analysis(r"\Working\farms_buffer1.shp",clipShape,r"\Working\buffer_clip1.shp")
arcpy.MultipartToSinglepart_management(r"\Working\buffer_clip1.shp",r"\Working\buffer_multi1.shp")
fcBuffer1 = arcpy.MakeFeatureLayer_management(r"\Working\buffer_multi1.shp","BufferTemp")
fcBufferSelect1 = arcpy.SelectLayerByLocation_management(fcBuffer1,"INTERSECT", r"\Working\buffer_sites.shp")
# Check for existence of old buffer in ArcMap before deleting
##if arcpy.Exists(outBuffer):
##arcpy.Delete_management(outBuffer)
#Export final Buffer to file
fcFinal = arcpy.CopyFeatures_management(fcBufferSelect1, outBuffer)
#Select sites within buffer
fcFarmsFinal = arcpy.SelectLayerByLocation_management(fcFarmsAll,"INTERSECT", outBuffer)
#Delete working files
arcpy.Delete_management(r"\Working\farms_buffer.shp")
arcpy.Delete_management(r"\Working\farms_buffer1.shp")
arcpy.Delete_management(r"\Working\buffer_clip.shp")
arcpy.Delete_management(r"\Working\buffer_clip1.shp")
arcpy.Delete_management(r"\Working\buffer_multi.shp")
arcpy.Delete_management(r"\Working\buffer_multi1.shp")
arcpy.Delete_management(r"\Working\farms_Select.shp")
arcpy.Delete_management(r"\Working\buffer_sites.shp")
arcpy.Delete_management(r"\Working\marineFarms.shp")
except:
print arcpy.GetMessages()
