Get Buildings That Intersect Floodplains for Each Municipality Python Script Sample for Blog

buildings_intersect_floodplains_by_municipality.py

# import arcpy and os modules
import arcpy, os

# Create text file for logging results of script
logFile = r'[path]\[to]\[folder]\Buildings_Intersect_Floodplains_Report.txt'
# variable to store messages for log file. Messages written in finally statement at end of script (not shown in sample)
logMsg = ''
# output location for shapefiles
out_folder_shp = r'[path]\[to]\[folder]\Buildings In Floodplains\Geodata'
# building footprints
bldg_footprints = r'[path]\[to]\[folder]\Geodata.gdb\Building_Footprints'
# fema floodplains
fema_floodplains = r'[path]\[to]\[folder]\Geodata.gdb\Floodplains'
# municipalities
muni = r'[path]\[to]\[folder]\Geodata.gdb\Municipality'
# municipalities fields
muni_fields = ['MUNI_NAME']
# create feature layer for municipalities
arcpy.MakeFeatureLayer_management(muni,'municipality')
# create feature layer for buildings
arcpy.MakeFeatureLayer_management(bldg_footprints, 'buildings')
# create feature layer for floodplains
arcpy.MakeFeatureLayer_management(fema_floodplains, 'floodplains')

# Create Search Cursor for Municipalities
# add message
logMsg += 'Creating search cursor on {}\n'.format(muni)
# create search cursor
with arcpy.da.SearchCursor(muni,muni_fields) as cursor:
   # loop through each record in municipalities layer
   for row in cursor:
      # add message
      logMsg += '\nSelecting buildings that intersect {}\n'.format(row[0])
      # attribute selection on municipality
      # SQL query
      where_clause = "MUNI_NAME = '{}'".format(row[0])
      arcpy.SelectLayerByAttribute_management('municipality', 'NEW_SELECTION', where_clause)
      # select buildings that have centroid in municipality
      arcpy.SelectLayerByLocation_management('buildings', 'HAVE_THEIR_CENTER_IN', 'municipality', selection_type='NEW_SELECTION')
      # get count of buildings that intersect municipality
      match_count_bldg = int(arcpy.GetCount_management('buildings')[0])
      # make sure features are selected before moving forward
      if match_count_bldg > 0:
         # select from selected buildings that intersect floodplains
         arcpy.SelectLayerByLocation_management('buildings', 'INTERSECT', 'floodplains', selection_type='SUBSET_SELECTION')
         # get count of selected buildings
         match_count_blg_floodplains = int(arcpy.GetCount_management('buildings')[0])
         # make sure features are selected before moving forward
         if match_count_blg_floodplains > 0:
            # add message - number of buildings in municipality
            logMsg += '\nThere are {} buildings that intersect floodplains in {}\n'.format(match_count_blg_floodplains, row[0])
            # export layer
            arcpy.CopyFeatures_management('buildings', os.path.join(out_folder_shp, 'Buildings_Intersect_Floodplains_{}.shp'.format(row[0])))
         else:
            logMsg += '\nNo buildings that are within {} intersect floodplains\n'.format(row[0])
      else:
         logMsg += '\nThere were no buildings that have their centroids in {}\n'.format(row[0])
      # end if/else
   # end for
# end with cursor