Terrain layer properties in ArcMap
You control all aspects of a terrain layer in ArcMap through the Layer Properties dialog box.
To access terrain layer properties in ArcMap, right-click the terrain layer in the table of contents and click Properties.
The General tab on the Layer Properties dialog box allows the display name and description to be modified. You can also set a scale range in which to display the terrain layer.
The Source tab shows the bounding extent of the terrain data along with its source and coordinate system.
The Symbology tab offers methods for representing a terrain layer. Terrains represent continuous surfaces such as elevation. The surface is represented as a set of facets formed by connecting data points at nodes to create adjacent triangles (TIN-based technology). Typically, you display a terrain dataset using color-shaded relief to depict elevation. You can also display the internal structure of a terrain—for example, nodes and edges—independently or on top of the shaded relief display.
Several symbology renderers exist for terrain datasets. By default, ArcMap displays the face elevation and breakline edges of the terrain.
Changing the symbology renderer for a terrain dataset
- Click the Add button.
- Click the renderer that represents the terrain feature you want to display and click Add.
- Click Dismiss when you are finished adding renderers. The list updates to show what you want to draw.
- Click an element in the Show list.
- Click the Up or Down arrow key to change the element's draw order.
The terrain features at the top of the list draw on top of those below them.
- Click OK.
The Display tab controls how the terrain dataset data is displayed as the view is changed in ArcMap.
Options include terrain preference settings, adding MapTips, displaying terrain resolution in the table of contents, scaling symbols, and layer transparency settings.
Rendering preference options
Use default drawing behavior—By default, the rendering performance is set to Use default drawing behavior, in which the terrain is displayed according to its pyramid definition. The current display scale determines which pyramid level to use.
Always use resolution—Always use resolution sets the terrain resolution to use a specific pyramid level. Once you have selected this option, choose the desired pyramid level resolution from the drop-down list. This option overrides the pyramid level definition and always displays the terrain at the selected resolution regardless of the map scale as long as the point limit is not exceeded.
Apply point limit—Apply point limit sets a size limit to the number of points used in the triangulation of the terrain layer surface. The default value is 800,000. If, for a given display extent, use of the settings would result in a surface that exceeds the specified point count, the layer will switch to a more generalized pyramid level. When this occurs, an asterisk will be displayed next to the resolution listed for the layer in the document's table of contents. To see the graphic, you'll need to make sure the resolution option on this tab is checked and the layer in the table of contents is maximized.
Lock surface—Lock surface will freeze the current state of the terrain surface. The purpose of this tool is to enable you to define a work area, of a reasonable extent and resolution, which you can subsequently zoom in on and pan around without repeatedly incurring the cost of surface regeneration or retrieving and triangulating measurements. To do this, first zoom to the extent of your work area and select the appropriate pyramid resolution on this dialog box, then increase the point limit (for example, a few million), if necessary, and click Apply. This might take a few minutes depending on how much data needs to be retrieved. When it is done, check the Lock surface check box. You can now zoom in and around your work area. This way, you pay a onetime, up-front cost in time, and subsequent maneuvers around your work area are faster.
Maintain Surface—Maintain Surface allows you to use the terrain dataset surface for analysis while the surface is not rendered in the display window. To turn off the display of the terrain dataset and maintain the underlying surface for analysis, uncheck all the renderers on the Symbology tab and check Maintain Surface on the Analysis tab. The terrain dataset will be updated and available for interpolation when panning and zooming around, even though it is not visible. If Lock Surface is engaged, all other properties, including Maintain Surface, are suspended.
The Analysis tab offers settings for using the tools on the 3D Analyst toolbar. By default, the analysis tools are only enabled when the terrain dataset is at full resolution (0).
Clicking the drop-down arrow allows you to set a resolution threshold for the interactive tools on the 3D Analyst toolbar. The tools are only enabled for use on this terrain surface when its display resolution is equal to or better than what's specified here.