Fundamentals of displaying surfaces in 3D
The ArcGIS 3D Analyst extension and ArcMap give you a variety of ways to symbolize and display the different types of GIS surface formats, such as rasters, TINs, terrain and LAS datasets. Rasters, TINs and LAS datasets can be easily displayed inside ArcScene using different symbology options.
Continuous rasters, also known as surface data, can be stretched to improve contrast. Categorical rasters, or discontinuous data (such as a lake because of its definable boundary with the surrounding landscape), can be symbolized using their unique values. Multiband rasters, such as satellite images and some aerial photographs, can be displayed as a red, green, and blue (RGB) composite or as a single stretched image. Feature data can be dynamically displayed as a raster. You can render cells with no data and background cells in different ways.
ArcScene and ArcMap allow you to symbolize TIN surfaces using the elevation values, aspect, or slope of each TIN facet. You can also show the nodes and edges of the TIN in several different ways. TINs cannot be displayed as visual layers in ArcGlobe.
Terrain datasets cannot be dynamically displayed in ArcScene but only in ArcMap and ArcGlobe.
LAS datasets can be displayed in both ArcScene and ArcMap.
You cannot add a mosaic dataset to ArcScene, but only in ArcMap and ArcGlobe.
All displayed raster and surface layers must have their base heights defined within the 3D view. Surface layers can reference themselves or other surface data to get this information. Discontinuous, or discrete, raster data must refer to separate elevation data or use a constant value or expression to define its z-values.
Examples of continuous data include these:
- Elevation data
- Temperature data
- Fire risk data
Examples of discontinuous data include the following:
- Thematic land-use data
- Rasterized feature data
- Remotely sensed image data
- Scanned maps
You can make all surfaces transparent and add depth and realism to a surface by shading it based on its position relative to a light source. You can also manipulate the appearance of the surface by setting the layer properties such as base resolution.
Note:Like all GIS data, surfaces should have a coordinate system defined. However, unlike traditional 2D GIS data, surfaces have the added spatial effect of defining Z (height) values, and this should be taken into account when deciding upon the coordinate system. It is recommended that the XY units and the Z units be the same - for example, a UTM (meter-based) raster surface should also model height values in meters.
Learn more about defining the coordinate system of raster surfaces.
Unexpected results may occur if you're using a geographic coordinate system in ArcScene.
Displaying raster surfaces in ArcScene
Layer properties help define how your raster surface will be displayed in 3D. Access the Layer Properties dialog box by right-clicking the layer in the table of contents and clicking Properties.
Raster data can be either continuous or discontinuous. Continuous raster data represents a surface. This surface may be a traditional elevation surface, or it may represent an analysis surface, such as the relative fire risk for a region. Discontinuous raster data, on the other hand, represents discrete blocks of information, such as an aerial photograph.
All supported raster data formats can be displayed in ArcScene as floating or draped layers. Only a continuous, single-band raster can be used as an elevation source for itself or other layers.
When displaying rasters in 3D, you need to set the base heights for the layer by defining its 3D layer properties. In ArcScene, to display a raster surface in 3D, the elevation values must come from a provided surface. A floating layer requires layer properties that directly specify its elevation source, which may be a constant value, a separate 3D surface data source, or itself. If the base surface is a raster, you can also set the resolution of the source raster.
Learn the steps to display raster surfaces in ArcScene
There are three symbology layer options by which to symbolize rasters:
- Grouping their values into a number of classes
- Stretching the values to enhance contrast
- Assigning each unique value in the raster to a color
How you display a raster depends on the type of data that it contains and what you want to show. Some rasters have a predefined color scheme; for others, ArcScene will choose an appropriate display method that you can adjust as needed. You can change display colors, group data values into classes, or stretch values to increase visual contrast.
For multiband rasters, you can choose three bands to display together in an RGB composite. This drawing method often improves your ability to distinguish features in multispectral images.
For complete details on display and symbology options for raster layers, see Displaying rasters and Improving the display of raster data.
Displaying TIN surfaces in ArcScene
TINs are made up of triangular facets and the nodes and edges that make up the triangles. They may also contain breaklines—lines that follow sets of edges that play important roles in defining the shape of the surface. Examples of breaklines are ridgelines, roads, or streams.
A TIN is used to describe a surface and does not necessarily have to be displayed in the 3D view. You can simply drape other data, such as an aerial photograph, over it to see the topography. However, you have the option to display the TIN as a layer in ArcMap or ArcScene if you want to. This may be required if you do not have other data to drape over the full extent of the TIN.
You can display just one type of TIN feature—for example, just the triangles—or all the TIN features. You can also symbolize each feature type using separate symbology. TIN nodes and triangles can be tagged with integer values to allow you to store additional information about them. These integer values can be used as lookup codes—for example, to indicate the accuracy of the input feature data source or the land-use type code for areas on the surface. The codes can be derived from fields in the input feature classes. You can symbolize tagged features with unique values.
For steps on displaying TIN surfaces by symbolizing different features, refer to the following topics:
Displaying terrain surfaces in ArcScene
A terrain dataset is a derived data source, calculated based on participating point, line, and polygon feature classes. It is displayed similarly to TINs, where the symbology is made up of triangular facets and the nodes and edges that make up the triangles.
By default, terrain layers cannot be directly displayed or used as elevation sources in ArcScene. If you want to consume a terrain dataset in ArcScene, you will need to export your area of interest to either a raster or a TIN.
To generate resourceful surface models for a 3D scene, export the terrain dataset or a portion of the terrain dataset that you want to work with in ArcScene using the 3D Analyst geoprocessing tools. You can use either the Terrain To Raster or Terrain To TIN tool to complete the conversion.
Displaying LAS dataset surfaces in ArcScene
A LAS dataset stores reference to one or more LAS files on disk, as well as to additional surface features. The LAS dataset can be displayed as either a surface or as points. The surface-based layer type is similar to TIN or terrain dataset layers in that it supports multiple display renderers. You can view the triangles colored by elevation range, slope, aspect, and contours. You can see the breaklines, triangle edges, and nodes of the triangulated surface. When a LAS dataset is added to ArcScene, the minimum bounding boxes representing the extents of each LAS file in the LAS dataset are shown each time the LAS data is drawn in the scene. These boxes disappear once each LAS file is loaded or reloaded.
For steps on displaying LAS dataset surfaces in ArcScene, refer to the following topics: