ArcPy ArcMap – Writing Python Script with Open Variables for ModelBuilder

arcmaparcpymodelbuilderparameters

I have the following script:

import arcpy
from arcpy import mapping

arcpy.env.workspace = r"C:\GIS\Test"
mxd = arcpy.mapping.MapDocument(r"C:\GIS\Test\Mxd_to_shape.mxd")
df = arcpy.mapping.ListDataFrames(mxd)[0]

#Variables
shp_input = "hellow.shp"
layer_output = "test"

arcpy.MakeFeatureLayer_management(shp_input,layer_output)
layer = arcpy.mapping.Layer(layer_output)
arcpy.mapping.AddLayer(df,layer,"AUTO_ARRANGE")

mxd.saveACopy(r"C:\GIS\Test\Mxd_a_shape2.mxd")
del mxd

arcpy.AddMessage("Ended process")

As you can see, I have defined variables in the previous script.
However, I need these variables to remain "open" to later transform the script into a sub-tool of a ModelBuilder model.
The need is that apparently having the pre-set variables in the script, wanting to change them as parameters in ModelBuilder does not work.

Best Answer

I recommend reviewing the ArcMap help topic on Integrating scripts within a model:

Python or other language scripts can be integrated into models by making the script into a script tool and adding the script tool to a model. This can be used when Python or other scripting language logic is needed to enhance a model or to access an external package or program from within ArcGIS.

The starting place for integrating scripts within models is the actual script. The script must be written in such a way that it can be integrated into the geoprocessing framework. For more information, refer to Writing a Python script.

Once the script is written, a script tool can be created and added to a toolbox. This script tool can be added to a model and used to bring additional functionality to the model.

Related Solutions

[GIS] Converting ModelBuilder to Python Script

I see several items that will need to be cleaned up. Going from top to bottom...

You need to use the entire toolbox path to import it. A stand-alone script won't know how to find it just by name. Also, open your toolbox properties and make sure you have given it an alias. That way you won't have to type out the whole name every time you use a tool from it.
The For loop will need to be put in python. The iterator is a modelbuilder-only tool. Python can't use it. It looks like you are iterating through a range? If so, that would be "for x in range(1, 20):"
You will need to fix your local variables so python can use them. The reason why you have a bunch of variables that all look alike is because your model is a chain. If your workflow processes are all using the same input, you don't need all the separate variables in python. So pare them down to one.
In your processes, you will need to change the input parameters so python can use them.

For example, instead of "%Value%", you will just put Value, i.e., instead of

 arcpy.Select_analysis(ElevationContourRingSimply, fdcb_Value_, "GRIDCODE <= %Value%")

you will put

 arcpy.Select_analysis(ElevationContourRingSimply, fdcb_Value_, "GRIDCODE <= " + str(Value))

or if GRIDCODE is a text column

 arcpy.Select_analysis(ElevationContourRingSimply, fdcb_Value_, "GRIDCODE <= \"" + str(Value) + "\"")

If you want to be able to input different parameters, you will need to add user input code at the top of the script. (Param1 = arcpy.GetParameterAsText(0)) If you do that, since you are making a stand-alone script (not running out of an ArcGIS toolbox), you will need to add code to check the user's inputs to make sure they are something that will work. Running scripts out of a toolbox saves you a lot of coding.
You will also want to add some error control. This comes in the form of a try, except, finally statement.

If you know ahead of time that your final tool will be a script tool, it is more efficient to code it as such from the beginning. Making a model first doesn't save you any time or effort. The only reason I ever do that is if the ESRI documentation on a tool is not very clear (at least to me), and I need to see how a working model actually shows up in python.

I hope this is helpful and gets you started.

ArcPy SQL – Using Variables in SQL Expression in ArcPy Script

The problem is in "arcpy.GetParameterAsText(0)" return a string to variable. When you try concatenate string to parse in SQL, you need include single quote between the strings.

Try this way:

SQL = "gridcode >= '" slp_min + "' AND gridcode <= '" + slp_max + "'"

Now, if values was float or integer, try change the variable attribution casting the type, like this:

slp_min = float(arcpy.GetParameterAsText(1))

slp_max = int(arcpy.GetParameterAsText(2))

Then you try concatenate like you write before.

Best Answer

Related Solutions

[GIS] Converting ModelBuilder to Python Script

ArcPy SQL – Using Variables in SQL Expression in ArcPy Script

Related Question