Hill Shading
You can use hill shading to emphasise the contours of a ground model displayed on the GeoPlan Window. Hill shading simulates a light source (the sun) which you can point towards your model:
- from any direction around the horizon
- from any angle between horizontal (0°) and directly overhead (90°)
You can also exaggerate the vertical scale to make contours stand out more clearly. InfoWorks ICM calculates the expected luminosity of each surface based on its angle relative to the light source. Increasing the vertical exaggeration effectively exaggerates these angles, and therefore increases the contrast between surfaces.
To control hill shading you need to load a Ground Model on the GeoPlan and then display the Ground Model. Then:
- Right click on the GeoPlan Window and choose Properties from the popup menu. This displays the GeoPlan Properties Dialog.
- Switch to the General Page. The hill shading options are set on this page.
- Use the On check box to switch hill shading on and off.
- Set the horizontal angle in the Azimuth box. 0° means the light source is pointing from the top of the view.
- Set the vertical angle in the Altitude box. 90° is directly overhead.
- Set the Vertical Exaggeration to give the best effect.
- Use the Apply button to test your changes until you get the desired effect.
- Click OK when finished.
The best effects from hill shading need to be found by trial and error, and will vary depending on the ground model.
Vertical exaggeration can emphasise valleys really well as long as you choose your Azimuth carefully. However, from some angles, depressions in the terrain can appear like hills, giving the effect that the topology is reversed. This is a strange effect of human perception - a well known optical illusion!
The only way to get round this is to make sure you know where the high and low points of your ground model are, and then choose settings that give a true representation of the terrain for the viewer.
