Building a terrain dataset using the New Terrain wizard

Lidar data, stored as either LAS files or ASCII files can be converted into multipoint features classes and managed in a geodatabase feature dataset. These multipoint feature classes can then be added to a terrain dataset using the New Terrain wizard in ArcCatalog or the Catalog window.

Terrain datasets can be generated from several different types of data. Such data can include lidar points, sonar points, breaklines and points derived from stereo photography, and other forms of survey data. The feature class geometry types supported for terrain datasets include points, multipoints, lines, and polygons.

Learn more about how to use the ASCII 3D to Feature Class tool

Learn more about how to use the LAS to Multipoint tool

Using the New Terrain wizard in ArcCatalog or the Catalog window

ArcCatalog or the Catalog window provides access to the New Terrain wizard to create terrain datasets. The New Terrain wizard is part of the ArcGIS 3D Analyst extension. To ensure you have the ArcGIS 3D Analyst extension installed and enabled, verify the extension name is checked in the Customize > Extensions dialog box. The New Terrain wizard is recommended for creating a terrain dataset interactively. For data automation, accomplished via scripts and/or models, use the terrain-related geoprocessing tools found in the 3D Analyst toolbox. For more information on using geoprocessing tools see: Building a terrain dataset with geoprocessing tools.

The following must be prepared prior to using the New Terrain wizard:

Step 1: Starting the New Terrain wizard

Accessing the New Terrain wizard in ArcCatalog or the Catalog window

Steps:
  1. Right-click the feature dataset to display the context menu.
  2. From the context menu, click New > Terrain.

Starting the New Terrain Wizard

Step 2: Using the New Terrain wizard—Terrain characteristics

The following must be included on the New Terrain dialog box:

Steps:
  1. Type a name for the terrain dataset.
  2. The feature classes within the feature dataset where the terrain is created are listed in the selection window. Choose the feature classes that are to be used to generate the terrain dataset by checking the check boxes next to the feature classes.
  3. Type the point spacing of the mass points.
NoteNote:

In most cases, the point spacing is supplied by the vendor along with the point data files. If the point spacing is not known, the Point File Information tool can provide a point spacing for the supplied data files.

Terrain characteristics

Step 3: Using the New Terrain wizard—Feature class characteristics

On this dialog window, determine how each feature class contributes to the definition of the surface within a terrain dataset. Each separate feature class requires settings. Use the drop-down menus by clicking in the table to choose the desired setting. Click the Advanced button to expose the advanced terrain settings for each feature class.

Normal settings:

Advanced settings:

Feature class characteristics

Step 4: Using the New Terrain wizard—Pyramid type

This step defines the pyramid type to use to build the terrain dataset. Pyramids allow the creation of a multiresolution TIN-based surface, which improves overall efficiency. They are used as a form of scale-dependent generalization of the mass points data.

Steps:
  1. Select a pyramid type to use to create the terrain pyramid levels.
    • Z Tolerance—Pyramid level resolution defined by the overall vertical accuracy at an associated scale range relative to the full-resolution data
    • Window Size—Pyramid level resolution defined by an equal-area window size at an associated scale range
  2. If the window size pyramid type is selected, indicate the point selection method to be used in the selection of the data point in each window.
  3. If the window size pyramid type is selected, optionally indicate whether further point thinning is required using the Secondary thinning method. The Secondary thinning method is used to further thin mass points over relative flat surfaces. A thinning threshold is required to specify the maximum difference in z a point can be from the selected window size point to be thinned out of the terrain.

Select pyramid type

Step 5: New Terrain wizard—Terrain Pyramid Properties

The terrain pyramid levels are created for a terrain dataset on this dialog box. The column indicating maximum scale is a reference scale threshold. A pyramid layer is used to represent a terrain dataset between its reference scale and the reference scale of the next coarsest level.

The column indicating the pyramid type will change depending on the identified pyramid type.

Steps:
  1. Click either the Calculate Pyramid Properties or Add button to add pyramid levels to the terrain pyramid levels window. Clicking the Calculate Pyramid Properties button will estimate default values.
  2. Refine and correct the pyramid levels based on knowledge of the data by highlighting the value and modifying it.

Terrain pyramid properties

Step 6: New Terrain wizard—Summary of terrain settings

The summary dialog box displays the settings that are to be used to build the terrain dataset.

Steps:
  1. Evaluate the selected settings for the terrain. If modifications are required, click Back to complete any changes.
  2. If the terrain is ready to be built, click Finish.
NoteNote:

Once the Finish button is clicked, a message appears showing the progress of the terrain build process.

Summary of terrain settings

Related Topics

2/10/2012