Reflectance Shading Methods
There are four reflectance methods available for color relief layers using Reflectance for the Terrain representation. To set the Reflectance method, click on the color relief layer to select it. In the Properties window, click on the General tab. Change the Terrain representation to Reflectance and change the Reflectance method to the desired method, described below.
Simple
Simple is the fastest of the shading methods, but produces a rather crude image. With Simple, the Horizontal (azimuth) and Vertical (zenith) values are fixed at 135 and 45 degrees, respectively, and cannot be changed.
Peucker’s Approximation
Peucker’s approximation uses a piecewise linear approximation. This method gives somewhat better results than the Simple method, but redrawing the map takes slightly longer. With Peucker’s approximation, the Horizontal (azimuth) and Vertical (zenith) values are fixed at 135 and 45 degrees, respectively, and cannot be changed.
Lambertian Reflection
Lambertian reflection assumes an ideal surface that reflects all the light that strikes it and the surface appears equally bright from all viewing directions. The Light Position Angles section allows the Horizontal (angle) and Vertical (angle) values to be specified with this option. This is the default Reflectance method.
Lommel-Seeliger Law
The Lommel-Seeliger law method is based on an analysis of light scattering from a surface. This method is a compromise between an ideal diffuser and a real surface. With some surfaces, this may actually give better results than the Lambertian reflection method. The Light Position Angles section allows the Horizontal (angle) and Vertical (angle) values to be specified with this option.