Default display

On the Default display page, you can set up how to display rasters and digital elevation models (DEM).

When a raster is displayed, an initial map layer is created automatically. You can control the default appearance of the map layer based on the metadata or the red, green, and blue (RGB) values you specify. That is, when the data has appropriate metadata, such as, wavelength, you can use it to determine the default display. Alternatively, when the data does not have appropriate metadata (or you perhaps do not want to use it), you can specify implicitly the RGB combination you want to use with multichannel datasets.

You can also control how to display a DEM by default. You can select from various map-layer types. With shaded-relief types, you can select additional options for illumination and contour.

To set up the default display of RGB data using associated metadata
- Select the Use metadata (when present) check box.
  Note: With this check box selected, the metadata of the first file read is used and applied to each subsequent image.
To specify the default RGB values
1. In the Red box, type or select a number for the channel that will provide the red display value.
2. In the Green box, type or select a number for the channel that will provide the green display value.
3. In the Blue box, type or select a number for the channel that will provide the blue display value.
To set up the default display of a DEM
- In the Default display for DEMs list, select the display type you want.
  - Grayscale shaded relief displays the digital elevation model (DEM) with grayscale hill-shading. The light source is from the top-left. It and the elevation values are used to cast the shadows.
  - Fixed color shaded relief displays the DEM with color hill-shading. The light source is from the top-left. It and the elevation values are used to cast the shadows. Colors are interpolated across elevation values to give a smooth gradation.
  - Dynamic color shaded relief displays the DEM using color hill-shading. The light source is from the top-left and elevation values are used to cast the shadows. The color display of the DEM is rerendered automatically as you pan or zoom in the viewer so that the colorization is applied only to the pixels being viewed currently.
  - Contoured color shaded relief displays the DEM using color hill-shading. A light source and the elevation values are used to cast the shadows. The colors are not interpolated; that is, the definition of the various contour intervals is crisp. DEM pixels within one interval use the same color in the map. If necessary, you can select additional options, such as adjusting the interval.
  - Grayscale displays the DEM as grayscale.
  - Pseudocolor displays the DEM as pseudocolor.
  With a selected shaded-relief type, you can click Options to set up the illumination source and contour, as applicable.