Let’s start by opening a tool from the Catalog window and running it using its graphical user interface (GUI).
- If by chance you still have the Buffer tool open from the previous section, close it for now so you can add some data.
- Create a folder on your machine at C:\WCGIS\Geog485. If you use a different path, be sure to substitute your path in the following examples.
- Download the Lesson 1 data and extract Lesson1.zip into your new folder so that the data is under the path C:\WCGIS\Geog485\Lesson1. This folder contains a variety of datasets you will use throughout the lesson.
- Open ArcMap and create a new empty map.
- Click the Add Data button and browse to the data you just extracted. Add the us_boundaries and us_cities shapefiles.
- Open the Catalog window if necessary and browse to the Buffer tool as you did in the previous section.
- Double-click the Buffer tool to open it.
Examine the first required parameter: Input Features. Click the Browse button and browse to the path of your cities dataset C:\WCGIS\Geog485\Lesson1\us_cities.shp. Notice that once you do this, a path is automatically supplied for the Output Feature Class. The software does this for your convenience only and you can change the path if you want.
A more convenient way to supply the Input Features is to just select the cities map layer from the dropdown menu. This dropdown automatically contains all the layers in your map document. However, in this example we browsed to the path of the data because it’s conceptually similar to how we’ll provide the paths in the command line and scripting environments.
- Now you need to supply the Distance parameter for the buffer. For this run of the tool, set a Linear unit of 5 miles. When we run the tool from the other environments, we’ll make the buffer distance slightly larger so we know that we got distinct outputs.
- The rest of the parameters are optional. The Side Type and End Type parameters apply only to lines and polygons, so they are not even available for setting in the GUI environment when working with city points. However, change the Dissolve Type to ALL. This combines overlapping buffers into a single polygon.
- Click OK to run the tool.
- The tool should take just a few seconds to complete. Examine the output that appears on the map, and do a “sanity check” to make sure that buffers appear around the cities and they appear to be about 5 miles in radius. You may need to zoom in to a single state in order to see the buffers.
- Click the Geoprocessing menu and click Results. This window lists messages about successes or failures of all recent tools that you've run.
- Expand the Buffer tool until you can see all the messages. They list the tool parameters, the time of completion, and any problems that occurred when running the tool. (See Figure 1.1.) These messages can be a big help later when you troubleshoot your Python scripts. The text of these messages is available whether you run the tool from the GUI, from the Python window in ArcMap, or from scripts.