After reviewing all the possible related solutions to my problem, I could not piece together a solution to process and import multiple sets of groundwater analytical data that contains different data types from CSV format (example below) into ArcGIS 10.1 for heat mapping (or generating isoconcentration lines).
Ultimately, I need a CSV file that contains only numeric data types.
As you can see, I have integer, floating point, and non-numeric values (e.g. ND = not detected, NA = not analyzed).
I can substitute NDs with 0's, but I don't know how to handle the NAs since they have no value but cause ArcGIS to interpret my fields as strings.
If I substitute the NAs with no value, then when I export my data to a shapefile, it automatically populates the blank fields with 0's which is not accurate.
I want to find a solution where I don't have to manually add a new field for each constituent and run the field calculator to redefine my data types.
I was hoping to find a ModelBuilder solution, but I couldn't figure out how to avoid the string problem.
I am not opposed to using Python directly, but I am not an experienced user.