ModelBuilder

ModelBuilder is an application in ArcMap to create, edit, and manage models. ModelBuilder is also known as a visual programming language from constructing and executing simple workflows to develop and run reusable and complex geoprocessing workflows and models.

Key Components


Models are workflows that string together sequences of geoprocessing tools, feeding the output of one tool into another tool as input. Model elements are the data and tools to work with, and are a basic building blocks of models. There are three type of model elements :


 * Tools
 * Tool elements are created when a tool is added from ArcToolbox. They perform several operations on geographic or tabular data.


 * Variables
 * Variables are elements in a model that hold a value or a reference to data stored on disk. There are two types of variables in models which are data and values. Data variables include field information, spatial reference, and path, while values variables contain anything but references to data stored on disk such as strings, numbers, and Booleans.


 * Connectors
 * Lines that connect data to tools are called connectors. The connector arrows display the direction of processing.

The ModelBuilder toolbox
The ModelBuilder toolbox contains of tools that support building models. Users can iterate the entire model or just an individual process using Iterators. ModelBuilder also has a set of supporting tools called Model Only tools.

Iterators
The Iterator toolset comprises of iterators that assist to repeat a process or set of processes on a set of inputs. Refer to the following An overview of the Iterator toolset Help page for more information on twelve iterators of ModelBuilder.

The Model Only toolset
The Model Only toolset comprises of tools that used to control the flow of processing. Some of the tools are simple support utilities. These tools are only used in ModelBuilder and not for Python scripting. Refer to the following An overview of the Model Only toolset Help page for more information.

Understanding process state
In a model, the sequence of processing is indicated by connector lines. A model process consists of a tool and all variables connected to it. There are four different processes when running a model, explained as such in the diagram on the left. Almost all ArcGIS system tools are empty (without color) when first added to a model. A process is ready-to-run when all required parameter values have been specified in the model. Ready-to-run processes are symbolized in color. Input data elements are blue, tool elements are yellow or orange, and output data (derived data) elements are green.

Advantages


The following are advantages of using ModelBuilder :


 * ModelBuilder is an easy-to-use application.
 * Users can create own tools with ModelBuilder and use them in Python scripting and other models.
 * ModelBuilder and scripting allow users to integrate ArcGIS with other applications.