The ArcGIS software that you use in this course contains hundreds of tools that you can use to manipulate and analyze GIS data. Back before ArcGIS had a graphical user interface (GUI), people would access these tools by typing commands. Nowadays, you can point and click your way through a whole hierarchy of toolboxes using ArcCatalog or the Catalog window in ArcMap.
Although you may have seen them before, let’s take a quick look at the toolboxes:
- Open ArcMap.
- If the Catalog window isn't visible, click the Windows menu, then click Catalog. If you hover over or click the Catalog item on the right side of your screen, you can make the Catalog window appear. Optionally, you can "pin" it down so that it doesn't hide itself.
- In the Catalog, expand the nodes Toolboxes > System Toolboxes and continue expanding the toolboxes of your choice until you see some of the available tools. Notice that they’re organized into toolboxes and toolsets. Sometimes it’s faster to use the Search window (Geoprocessing > Search For Tools) to find the tool you need instead of browsing this tree.
Let’s examine a tool. Expand Analysis Tools > Proximity > Buffer, and double-click the Buffer tool to open it.
You've probably seen this tool in past courses, but this time, really pay attention to the components that make up the user interface. Specifically, you’re looking at a dialog with many fields. Each geoprocessing tool has required inputs and outputs. Those are indicated by the green dots. They represent the minimum amount of information you need to supply in order to run a tool. For the Buffer tool, you’re required to supply an input features location (the features that will be buffered) and a buffer distance. You’re also required to indicate an output feature class location (for the new buffered features).
Many tools also have optional parameters. You can modify these if you want, but if you don’t supply them, the tool will still run using default values. For the Buffer tool, optional parameters are the Side Type, End Type, Dissolve Type, and Dissolve Fields. Optional parameters are typically specified after required parameters.
Click the Show Help button in the lower-right corner of the tool (if it says Hide Help then you’re already viewing help). You can now click on any parameter in the dialog to see an explanation of that parameter appear in the right-hand window.
If you’re not sure what a parameter means, this is a good way to learn. For example, with the help still open, click the Side Type input box on the Buffer tool (right where it says "FULL"). The Help explains what the Side Type parameter means and lists the different options: FULL, LEFT, RIGHT, and OUTSIDE_ONLY.
If you need even more help, each tool is more expansively documented in the ArcGIS Desktop Help (with Python examples!). You could go directly to the Buffer tool help by clicking the Tool Help button in the tool dialog box, but in this course you'll often want to get to these help pages without opening the tool itself. Below are the steps for doing so.
- From the main menu of ArcMap, click Help > ArcGIS Desktop Help. Optionally, for the most up-to-date help, you can use Esri's Web-based help. (All links to the Help in this course will open the Web Help.)
- Under the Contents tab of the Help system, expand Desktop > Geoprocessing > Tool reference. Notice that the help topics in this section are organized into toolboxes and toolsets, paralleling the layout of the ArcGIS System Toolboxes.
- Continue navigating the help table of contents to Analysis toolbox > Proximity toolset > Buffer. Scroll through the entire topic examining all the information that is given about the Buffer tool. Here you get tips about what the Buffer tool does, how to use it, and how to supply all of its parameters.
- Still within the Buffer topic, scroll to the section marked Code Sample. Every tool's help topic has these programming examples showing ways to automatically run the tool. These examples are written in Python, and they will be extremely valuable to you as you complete the assignments in this course. Always check the Geoprocessing Tool Reference in the Help if you’re having trouble getting a tool to run in Python.