Turning code into a script and parameterizing?

Question

I have python code that I want to turn into a script.

I want the end user to be able to navigate to the feature class the code should be run on.

The code I have currently speaks to a specific feature class and doesn't allow for picking what feature class the code is to be run on.

How do I change my code so I can have the parameters in the script allow the end user to pick what feature class the code should be run on?

This is the piece of code I need to change to allow the end user pick the feature class..

What do I need to change in my code to allow for the peramiters I set up in the script to replace this line of code? I need fc to equal the input the end user selects not a specific feature class as the code currently stands

Answer 1

That line of code simply has to be changed to:

fc = arcpy.GetParameterAsText(0)  # 0 assumes that it is the first parameter defined on your tool dialog

but you also need to configure the parameter on your tool dialog.

I recommend reviewing:

• Accessing parameters in a script tool
• Understanding script tool parameters.

Answer 2

You want to make use of Python functions. This allows you to make dynamic tasks and allows for code re-usability.

If you are wanting to make an input optional, say related to your question Calculating geometry for feature class with x/y and Lat/Long values in different projections? you could do this:

import arcpy

def getLatLong(fc, lat_field, long_field):
    """add lat/long fields

    fc -- path to feature class or shapefile
    lat_field -- latitude field to populate
    long_field -- longtitude field to populate
    """

    # add fields if they don't exist
    fieldList = [f.name for f in arcpy.ListFields(fc)]
    for f in [lat_field, long_field]:
        if f not in fieldList:
            arcpy.management.AddField(fc, f, 'DOUBLE')

    # populate lat/long fields
    wgs = arcpy.SpatialReference(4326)
    fields = ['SHAPE@XY', lat_field, long_field]
    with arcpy.da.UpdateCursor(fc, fields, spatial_reference=wgs) as rows:
        for row in rows:
            row[1:] = row[0] 
            rows.updateRow(row)

if __name__ == '__main__':

    fc = r'C:\TEMP\UofM_cc.shp'
    getLatLong(fc, 'Latitude', 'Longitude')
    print 'done'

Because this is a Python function, you can pass any point feature class in you want and it will do the coordinate conversion.

This could also be used for a script tool where you could pass in parameters like this:

getLatLong(*[arcpy.GetParameterAsText(i) for i in range(arcpy.GetArgumentCount())])

And thanks to Paul for mentioning the spatial_reference option for the update cursor. I always forget about that!