ModelBuilder is Esri’s graphical interface for making models. You can drag and drop tools from the Catalog window into the model and “connect” them, specifying the order in which they should run.
Although this is primarily a programming course, we’ll spend some time in ModelBuilder during the first lesson for two reasons:
ModelBuilder is a nice environment for exploring the ArcGIS tools, learning how tool inputs and outputs are used, and visually understanding how GIS modeling works. When you begin using Python, you will not have the same visual assistance to see how the tools you’re using are connected, but you may still want to draw your model on a whiteboard in a similar fashion to what you saw in ModelBuilder.
ModelBuilder can frequently reduce the amount of Python coding that you need to do. If your GIS problem does not require advanced conditional and iterative logic, you may be able to get your work done in ModelBuilder without writing a script. ModelBuilder also allows you to export any model to Python code, so if you get stuck implementing some tools within a script, it may be helpful to make a simple working model in ModelBuilder, then export it to Python to see how ArcGIS would construct the code. (Exporting a complex model is not recommended for beginners due to the verbose amount of code that ModelBuilder tends to create when exporting Python).