Choose pollutant coefficient type based on a shapefile.


Add ability to choose which pollutant coefficient type (1-4) is used for a particular pollutant based on attributes within a shapefile. This should be specified for each pollutant individually, perhaps with an option to use a previously identified selection.

The simplest way to do this would be to require the shapefile to have an attribute with an integer value 1-4 in it. Then pick type 1-4 based on this value. Different pollutants could have different attributes within the same shapefile. I suggest this as an initial approach rather than using a calculate on the fly approach where the user sets upper and lower bounds and the program figures out which polygons are which.