How To Add Values to an Attribute Field Based on a Selection - Python

Question

Alright another problem that I have. I am trying to give a priority ranking to lots based on various criteria. Basically I have 7 areas that are criteria, if lots overlap each other the criteria is added up and given a sum value (so the highest number could be 7). Now I am trying to create a python script that basically goes through my criteria and adds a value to a field added to an attribute table

For example, I would do a select by location for lots that are within 30m of wetlands - if YES then the field "CRITERIA" would be given a 1, if no it would be a 0 this same selection idea would be done for the rest of my criteria - then what I need is to have it total up the 1's that are in each row into a separate "RANKING" field.

Answer 1

If you select features in a layer, Field Calculator will only run on the selected features. So here's what I would do:

#Names of layers in table of contents
Lots_lyr = "Lots"
CriteriaList = ["Criterion1","Criterion2","Criterion3","Criterion4","Criterion5","Criterion6","Criterion7"]

#Add field that contains the sum of criteria
arcpy.AddField_management(Lots_lyr,"CriteriaSum","SHORT")

#Loop through 7 criteria layers
for Criterion in CriteriaList:

    #Select lots within range
    arcpy.SelectLayerByLocation_management(Lots_lyr,"WITHIN_A_DISTANCE",Criterion,"30 meters")

    #Increment sum for selected lots via field calculator
    arcpy.CalculateField_management(Lots_lyr,"CriteriaSum","!CriteriaSum! + 1","PYTHON")

Note: I have not tested this myself