Selecting options for shaded relief

In the Shaded Relief Options window, you can set up how the imagery is illuminated and, if applicable, contoured.

With each available shaded-relief option, you can adjust the illumination according to azimuth and altitude.

Illumination is the location of the diffuse light source that is used for the hill shading. Azimuth is the angle from north of the light source. Altitude is the angle of the light source from the horizon.

Conceptually, to help you understand illumination, you can visualize a line that connects the position of the light source to the top-left pixel of the digital elevation model (DEM). The azimuth angle is the azimuth of this line in degrees clockwise from north (top of the image). The altitude is the angle of the line in degrees from the horizontal.

Note: The options under Contoured Color Shaded Relief are available only when shaded-relief type is contoured.

To adjust the light-source location
- Under Illumination, do one or more of the following:
  - In the Azimuth box, type or select the angle, in degrees, from north of the light source.
    The value you enter can be any number ranging from zero through 360.
  - In the Altitude box, type or select the angle from the horizon, in degrees, of the light source.
    The value you enter must be a number ranging from zero through 90.
To adjust the contour
- If available, under Contoured Color Shaded Relief, do one or more of the following:
  - To adjust the starting height of the contours, type or select the elevation you want in the Contour starting elevation box.
  - To adjust the step size of the elevation between contours, type or select the number you want in the Contour interval box.
    Pixels within one interval will use the same color in the map.
For example, with a starting elevation of 20 and an interval of 10, pixels ranging from 20 through 30 will be one color, and pixels ranging from 30 through 40 will be the next color, and so on. However, with a starting elevation of 7 and an interval of 10, pixels 7 through 17 will be one color, pixels 17 through 27 will be the next color, and so on.

Tip: Adjusting the elevation and interval can be useful when you want to have a nonzero baseline for your contours.
To preview your changes
- Click Apply.