Creating Spatial Feature Classes Based on Proximity, Overlay, and Attributes - Introducing Geographic Information Systems with ArcGIS - page 414

2. Start ArcMap with a new Blank map. In the folder

___IGIS-Arc_ YourInitials \Trivial_GIS_Datasets

you will find a file geodatabase named Buffer_TicTacToe.gdb. Find the feature class named
TicTacToe (in TicTacToe_FDS). Display it in ArcMap. Set the map units and display units to
Meters. After setting Distance to Meters in the Measure window, determine the width of
TicTacToe: _____________ meters. Open the attribute table from the T/C. How many lines
are there? ________ Identify some of them. What is the length of each? ____________
meters.

The concept of buffering is pervasive in GIS. Over the years, ESRI has developed several tools to do the
operation. For geodatabases, we will explore two of them. The one we will use first is called the Buffer
Wizard. It is not automatically available in ArcMap or ArcToolbox, so you will have to add it. In addition to
getting the wizard, you will also learn something of the way the software can be customized. The Buffer
Wizard will be added to the Tools menu in the following step.

3. In ArcMap select: Customize > Customize Mode > Commands > tools (from the Categories
list). Click Buffer Wizard in the Commands list. Drag it to the Geoprocessing menu on the Main
menu, but don't let go of it yet. The Geoprocessing menu will open. Drag it down to just barely
below Buffer and release the mouse button. The wizard is now one of the geoprocessing tools
you can use. Close the Customize dialog box.

4. Click on the Buffer Wizard tool. Use it to buffer the lines of TicTacToe, making a File
Geodatabase Feature Class named TicTacToe_BUF with the following characteristics:

A specified distance of 5 meters (you have to set the buffer distance units)

❏

❏ Barriers not dissolved between buffers

Saved in ___IGIS-Arc_ YourInitials \Trivial_GIS_Datasets \Buffer_TicTacToe.gdb\
TicTacToe_FDS

❏

with the name TicTacToe_BUF (Careful: it's not a shapefile.)

5. TicTacToe_BUF should appear on your ArcMap display, probably in brown. If necessary, drag the
T/C entry TicTacToe_Buf below TicTacToe. Make sure you can see both feature data classes,
changing the line color and/or width of TicTacToe as necessary. This image should give you a
good idea of what buffering is all about. Note that the ends of some buffers cover the ends of
others, and that the buffer distance is applied around the endpoints of the lines. Turn off
TicTacToe. Note that each of the 12 lines is buffered. Open the polygon Attribute Table
of TicTacToe_BUF. What are the names of the fields? _______, _______, _______, _______,
________. How many polygons are there in TicTacToe_BUF? _____. Identify records to determine
which polygon is which. What is the area of each polygon, to one decimal place? _________.
Why isn't the buffer 1000 square meters (100 meters long times 10 meters wide)? __________
_______________________________________________

Some points are important here: