Introducing Geographic Information Systems with ArcGIS: A Workbook Approach to Learning GIS, 3rd Edition

Making a Terrain

Because of the very large data sets involved, making a Terrain is somewhat involved. Here is a summary of the steps that you will use.

• In the 3-D_Data folder in your own workspace you will navigate to Terrain_Data
• Examine TXT and XYZ files of LIDAR points
• Look at some ancillary files
• Make a geodatabase and feature dataset to hold the terrain.
• Import the ancillary files
• Determine the average point spacing of the LIDAR data
• Convert the XYZ data to multipoints and place them into the feature dataset
• Determine pyramid levels and make the Terrain feature class
• Build the Terrain feature class
• And finally you will examine the Terrain

Note: Another way to make a Terrain is to use what is called the New Terrain Wizard. You can find it by right-clicking the feature dataset name in the geodatabase (in our case you would right-click Zone in Example.gdb), click New, then Terrain to bring up a New Terrain window.9

In Chapter 2 you looked at a Terrain feature class in the area of a bend in the Kentucky River. In the following steps, you will actually produce a Terrain from basic LIDAR data and some ancillary data. One thing about LIDAR data is that the dataset is usually quite large. It is not unusual for a LIDAR file to contain tens of millions of points. The standard, public format of LIDAR data is the LAS file. It is a binary file that stores not only point coordinates (x, y, and z) but also intensity values. Because we are primarily interested in making a feature class ...