Assigning different classes using ArcGIS Field Calculator

Dastageerkhan

below is the code with what I have come up with. I have two columns, one name First_kopp that have the classes CT, WT, ST ranging from 1-9, and the second column is named First-fros. There are conditions that have to be met based on both columns as expressed in the code below, however, thiS Code does not seem to work:

def reclass(FIRST_KOPP , FIRST_FROS):
   if 'CT' in FIRST_KOPP: 
               return "High frost risk"
   elif 'ST1' or 'ST2' or 'ST3' in FIRST_KOPP:
               return "Frost free"
   elif 'ST1' or 'ST2' or 'ST3' in FIRST_KOPP and 'Moderate frost risk' or 'High frost risk' in FIRST_FROS:
               return "Low frost risk"
   elif 'ST4' or 'ST5' or 'ST6' or 'ST7' or 'ST8' or 'ST9' in FIRST_KOPP:
               return "Frost free"
   elif 'WT' in FIRST_KOPP and 'Frost free' in FIRST_FROS:
               return "Low frost risk"
   else:
               return FIRST_FROS

 

CodyScott

Two parts are going on here. 

First the in check is going to be True every time as it is written. So regardless of the value given it should return either "High frost risk" "Low frost risk" when using "CT" or anything else respectively. Updating, as dan mentioned, to checking if the value is in a list will solve this check.

 

Second part is based on the elif for ST1. When it sees ST1, ST2 or ST3 it proves True and it is going to step into that block. So it will never reach the next check, which incorporates the FIRST_FROS variable.

Two possible solutions.

1. invert the elif statements so your FIRST_FROS check comes before the check without FIRST_FROS.

2. add a nested if within the ST1... check to see if that FIRST_FROS check is True or not.

Option 1

 

 

def reclass(FIRST_KOPP , FIRST_FROS):
    if FIRST_KOPP in ['CT']: 
        return "High frost risk"
    elif FIRST_KOPP in ['ST1', 'ST2', 'ST3'] and FIRST_FROS in ['Moderate frost risk', 'High frost risk']:
        return "Low frost risk"
    elif FIRST_KOPP in ['ST1', 'ST2', 'ST3']:
        return "Frost free"
    elif FIRST_KOPP in ['ST4', 'ST5', 'ST6', 'ST7', 'ST8', 'ST9']:
        return "Frost free"
    elif FIRST_KOPP in ['WT'] and FIRST_FROS in ['Frost free']:
        return "Low frost risk"
    else:
        return FIRST_FROS

 

 

 

Option 2

 

 

def reclass(FIRST_KOPP , FIRST_FROS):
    if FIRST_KOPP in ['CT']: 
        return "High frost risk"
        
    elif FIRST_KOPP in ['ST1', 'ST2', 'ST3']:
        if FIRST_FROS in ['Moderate frost risk', 'High frost risk']:
            return "Low frost risk"
        else:
            return "Frost free"

    elif FIRST_KOPP in ['ST4', 'ST5', 'ST6', 'ST7', 'ST8', 'ST9']:
        return "Frost free"
        
    elif FIRST_KOPP in ['WT'] and FIRST_FROS in ['Frost free']:
        return "Low frost risk"
    else:
        return FIRST_FROS