ModelBuilder is a visual tool in ArcGIS Pro that allows for the creation, editing, and execution of automated geospatial analysis workflows. This tool enables the development of customized models that can be reused in other projects, thereby increasing efficiency in spatial data analysis. Additionally, it facilitates the integration of other tools, such as programming languages like Python and R.
Generally, it can automate geospatial processes, such as watershed delineation or the interpolation of precipitation and temperature data. In this example, the complete process of delineating a watershed, as described previously, is automated. This is useful for replicating the process for another watershed by only changing the input data, such as the DEM and discharge point.
Accessing ModelBuilder
In the Analysis tab within the Geoprocessing group, select ModelBuilder. This action opens a new tab where tools can be added sequentially. From the Geoprocessing panel, the Fill tool should be dragged into the window. Double-clicking the tool opens a configuration dialog. For this example, the file DEM_basin.tif is used as input, following previously explained configurations.
Workflow Automation with “ModelBuilder”.
Adding and Configuring Tools
The next step is to add the remaining tools in sequence, such as Flow Direction, Flow Accumulation, Con, and others, connecting each one. This process is intuitive, using the output of one tool as the input for the next. When configuring each tool, available Model Variables can be selected as input data.
For instance, to configure the Con tool, the result of the Flow Accumulation tool is used as input and linked with an arrow. Correctly configured tools appear in yellow; unconfigured tools remain gray. Input data appear in blue, and output data in green.
Configuring a tool in “ModelBuilder”.
Executing the Model
Once all tools are configured and connected in the ModelBuilder tab, additional options become available. These include exporting the model (e.g., as a Python script), customizing the display, and performing iterative functions for repetitive tasks.
To execute the model, click the Run button within the Run group. If the resulting layers do not automatically appear on the map, right-click on them and choose Add To Display.
Model for automating the procedure in watershed management.
Parameterizing the Model
If the model is intended to be used as a tool for similar processes, input and output parameters must be defined. Right-click on any parameter and select Parameter to activate it, which assigns the letter “P” to that element. This action ensures that the model awaits user input when executed.
It is also recommended to rename the parameters with descriptive names using the Rename option to facilitate understanding and usability of the model.
Creating Variables and Expressions
To create a variable from a parameter such as an expression, right-click on the desired tool (e.g., Con) and select Create Variable > From Parameter > Expression. This allows for the customization of settings like hydrological network density.
Model Properties and Execution Interface
To configure the title and other information for the model, go to the ModelBuilder tab, find the Model group, and click on Properties. Regularly saving progress with the Save button is recommended.
Using the Model > Open Tool button, the created tool can be accessed. This interface allows the user to select the DEM, set discharge points, define expressions, and specify names and directories for output layers.
Creation of a tool with “ModelBuilder”.
