Vertical Display Options

The Vertical Display options allow you to control how terrain elevation data is

displayed. The configurations can be adjusted to suit your needs. If you want to change colors, simply click on the color swatch to change it.

Shader Options. To view terrain elevation data, you can choose several algorithms from the dropdown menu to color and shade the loaded elevation data. Selecting the Select built-in shader as default radio button will allow you to choose from the following algorithms:

 Atlas Shader. The Atlas Shader is the default shader, and generally provides good results for any loaded elevation data.

 Color Ramp Shader. The Color Ramp Shader displays ramps of color: blue for low elevations to red for the highest elevations.

 Daylight Shader. The Daylight Shader colors all elevations the same shade and is only useful while Hill Shading is enabled.

When using this shader, you may customize the following options:

 Surface Color: sets the calculated surface intensity color.

 Global Shader. The Global Shader shades elevation datasets that cover large areas of the Earth such as Terrain Base and GTOPO30, to provide stunning results for these datasets.

 Gradient Shader. The Gradient Shader moderates coloring with elevation between the low elevations and the high elevations.

The actual colors ramped between can be selected in the Shader Options panel:

 Low Color: Sets the lowest elevation value color.

 High Color: Sets the lowest elevation range color.

 HSV Shader. The HSV Shader maps the elevations onto the HSV (hue saturation value) color space.

Mapping can be configured in the Shader Options panel:

 Low Color Start (Advanced): Sets where the lowest elevation will be on the HSV color range.

 Value (Advanced): Modifies the HSV value parameter.

 Saturation (Advanced): Modifies the HSV saturation parameter.

 Range: Modifies how much of the full HSV range is to be used--increasing this value leads to color wraparound.

 Reverse Colors: Reverses the orders of colors used for shading.

 Slope Shader. The Slope Shader colors loaded terrain data by the slope of the terrain rather than the absolute elevation. This shader allows you to identify the portions of the terrain that are relatively flat versus those that are relatively steep.

The definitions of "flat" and "steep" are the configurations for the Shader Options panel:

 Minimum Slope -> Slope Value: Allows you to set the slope at or below whichever Minimum Slope Color is used.

 Minimum Slope -> Color: Specifies the color with which all parts of the terrain with a slope at or below the Minimum Slope Value will be shaded.

 Maximum Slope -> Slope Value: Allows you to set the slope at or above whichever Maximum Slope Color is used.

 Maximum Slope -> Color: Specifies the color with which all parts of the terrain with a slope at or above the Maximum Slope Value will be shaded.

 Smooth Gradient: Specifies that all portions of the terrain with a slope between the Minimum Slope Value and the Maximum Slope Value will be colored with a smooth gradient of colors that vary with the slope from the Minimum Slope Color to the Maximum Slope Color.

 Custom Color: Specifies that all portions of the terrain with a slope between the Minimum Slope Value and the Maximum Slope Value will be colored with a single color that can be modified with the Select button.

Alternatively, you can choose to use custom shading created from system plot bands.

110  Main Project Windows

Hill Shading. Select the Enable Hill Shading option to view elevation data as a

shaded relief. With the option on, shadows will be generated using the loaded elevation data along with the remaining settings on this panel. The Vertical Exaggeration setting is used to control the exaggeration of relief features.

When this option is turned off, the map will appear flat, with elevations distinguished only by color. Selecting the Select custom shader as default radio button will open Shader Options similar to those shown in the dialog below:

When using this option, select a plot band from the dropdown menu, and the current configurations for that plot band will appear in the frame below. To change the configurations, click Edit and the following window will appear:

Light. The Lighting Direction option sets the position of the light source (the "sun") for hill shading. Note that cartographic azimuth and altitude are used. 0 azimuth means the sun is to the north, 90 azimuth means the sun is to the east, etc. An altitude of 90 means that the sun is directly overhead, while an altitude of 0 means the sun is on the horizon.

Use the Ambient Lighting option to brighten up dark datasets or to dim bright datasets.

Water Display. The Water Level setting controls the level at which water is displayed.

The default is set at an elevation of 0 meters above sea level. Use this to simulate different flood and sea level change scenarios.

The Water Transparency setting controls the clarity of the water displayed if configured to show water. Clearer water allows more underlying reliefs to show through, while opaque water allows none.

112  Main Project Windows