1. Python, Toolboxes, Tools & Script Tools
Accessing ArcGIS Geoprocessing tools with Python
Creating a toolbox
Adding script tools to a custom (TBX) or Python (PYT) toolbox
Tool and parameter messages
Error trapping

2. ArcToolbox & Geoprocessing*
ArcToolbox
Toolbox * *
Tool
Toolset
Tools may have same name if they are in different toolboxes Example: Clip_analysis
Clip_management
System tool
Model
Toolboxes, Toolsets, Tools
depend on license
Example:
Excel Toolset
Script
GIS4201 Week 3 2

3. Finding tools

4. Accessing ArcGIS Geoprocessing tools
GUI
Python Window
Models
Scripts
Run in PythonWindow, PyScripter/IDE, or command line
GIS4201 Week 3 4

5. Using ArcGIS tools with Python
To use any tool …
import arcpy
arcpy.<ToolName>_<ToolboxAlias>(args)
OR …
from arcpy.ToolboxAlias import as abbrev
ToolName
ToolboxAlias

6. Using ArcGIS tools with Python
Open the tool and get Tool Help

7. Using ArcGIS tools with Python
… and scroll down to Syntax and Code samples

8. Tool Result object Result inputCount: Integer maxSeverity: Integer
messageCount: Integer
outputCount : Integer
resultID: String
status : Integer
cancel() : Void
getInput(index : Integer) : Recordset or String
getMapImageURL({parameter_list}, {height}, {width}, {resolution}) : String
getMessage(index : Integer): String
getMessages({severity : Integer}) : String
getOutput(index : Integer) : Object
getSeverity(index : Integer) : Integer

9. Creating script tools To create a script tool, you need three things:
A toolbox
A precise definition of the parameters of your script

10. Create a script From scratch … Using ModelBuilder
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Create a script
From scratch …
Write and debug in PyScripter
Use sys.argv for script parameters/arguments to start
Once script is working, add it to a toolbox …
Using ModelBuilder
Create a model
Export to Python
Edit in PyScripter (might not work in ModelBuilder after edit)

11. Create a Toolbox Create a custom toolbox (.tbx)
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Create a Toolbox
Custom location
Create a custom toolbox (.tbx)
Or a Python Toolbox (.pyt)
Default location
C:\Users\<username>\AppData\Roaming\ESRI\Desktop10.2\ArcToolbox\My Toolboxes

12. To create a script tool, you need three things:
A toolbox
A precise definition of the parameters of your script
Custom or Python?
If you use or are planning to use significant validation code in your script tool, almost certainly you will find the experience more straightforward in a Python toolbox.

13. Creating Custom/Python Toolbox
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Creating Custom/Python Toolbox
Custom (.tbx)
Define Toolbox Alias, Description, Help, etc.
Add script to Toolbox (“separate” from .tbx)
Define parameters (Input/Output, Type, etc.) using wizard
Python (.pyt)
Add script to .pyt (“embedded” in .pyt)
Define parameters by editing functions within .pyt

14. Define Toolbox Alias & Description
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Define Toolbox Alias & Description
Alias in Properties window of PYT is read-only.
Change in PYT file …

15. Add script tool to Custom Toolbox
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Add script tool to Custom Toolbox
TBX

16. Add script tool to Python Toolbox
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Add script tool to Python Toolbox
PYT
The tools attribute of the Toolbox contains a list of “Tools” in the Python Toolbox.
Change the name of the default (Tool) to a new name.

17. Add script tool to Python Toolbox
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Add script tool to Python Toolbox
The execute method in the Tool class is run when the tool is executed. The source code for the script can be in this function, in a function called by statements in execute, or in an imported module.

18. Defining input parameters - TBX
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Defining input parameters - TBX
Like sys.argv without 1024 byte
limit and only used in script tools

19. Defining input parameters - PYT
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Defining input parameters - PYT
The list of parameters is defined in the getParameterInfo method of the tool.
Create a parameter using the arcpy.Parameter class Change params from None to a list (or not). As long as the function returns a list, the tool will work.
The Parameter filter property can be used to constrain values:

20. Defining input parameters - PYT
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Defining input parameters - PYT
The datatype of a Parameter is defined by a datatype keyword. The complete list is in ArcGIS help …

21. Value Lists Value Lists constrain values in scripts … TBX PYT
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Value Lists
Value Lists constrain values in scripts …
TBX
PYT

22. Defining output parameters
To create a script tool, you need three things:
A script
A toolbox
A precise definition of the parameters of your script
Defining output parameters
Tools should have an output esp. when the output could be used as input to another tool in ModelBuilder
TBX
PYT
The output parameter and dependency on an input parameter is defined in getParameterInfo.
parameterType = "Derived" direction = "Output"
paramOut.parameterDependencies = [paramIn.name]
# Set output parameter #
arcpy.SetParameterAsText(1, outFCName)
Ref: Setting output parameters …
Ref: Defining parameters in Python Toolbox

23. Using script tool parameter values in the script
Custom Toolbox (TBX)
In script associated with script tool (separate or embedded in TBX)
Python Toolbox (PYT)
In PYT file, class definition associated with the script tool …

24. Tool Messages
Refer to Writing messages in script tools in help.arcgis.com

25. Parameter messages
Used for warnings or errors when parameter values change (before tool is executed)

26. Error trapping
GetMessages(2)  Messages with severity of 2 = Error Messages

27. Enable PYT editing in PyScripter
Change “Open dialog Python filter” from
Python Files (*.py;*.pyw)|*.py;*.pyw to
Python Files (*.py;*.pyw;*.pyt)|*.py;*.pyw;*.pyt