I have two polygon feature classes: Basins, and Nexrad. Nexrad contains a field called 'value' which contains floating point numbers. I am trying to populate a new field with the sum of 'value' for all intersecting nexrad polygons for each basin feature. I am trying to loop through each basin, select all nexrad polygons that intersect the selected basin, calculate the sum of the 'value field in nexrad, and add that sum to a new field in the basins. Right now my script loops through correctly but only adds the sum from the last 'select by location'.
# Import Modules
from arcpy import env
# Set environment and workspace
env.workspace = r"W:\Citrix\34000s\34624\001\GIS\RainfallDepthTool\RainfallDepth_NK.gdb"
arcpy.env.overwriteOutput = True
print ("Environment set!")
# Set ariables
basins = r"W:\Citrix\34000s\34624\001\GIS\RainfallDepthTool\RainfallDepth_NK.gdb\Basins"
nexrad = r"W:\SAN\34000s\34624\001\DataIn\NEXRAD_9_22\shp\hourly\KEWX_N1P_20180922_075800.shp"
# Add a field to the basins to be populated with Nexrad polygon value
# Create Feature Layers
print ("Layers created!")
field = 'Shape@'
with arcpy.da.SearchCursor('basinLyr', field) as cursor:
for row in cursor:
# Get geometry to use in select by location
geom = row
# Select nexrad polygon that intersect the selected basin
x = arcpy.SelectLayerByLocation_management('nexradLyr', 'INTERSECT', geom, '', 'NEW_SELECTION')
# Calculate the sum of the 'value' field in the selected nexrad polygons
field = arcpy.da.TableToNumPyArray (x, 'value')
sum = field['value'].sum()
print ('Field Calculated!')