Visualizing data in two dimensions (x,y) can be confusing enough. When the third dimension (z) is added, it is helpful to try and visualize what we you are about to see, before seeing it.

This page will help in visualizing the functionality of the DDD and aid in creating useful and comprehensible images.

Let's start with an orthogonal axis configuration, with a x, y, and z axis.

some axes

Important: The X Rotational axis runs left-right across the viewer's monitor. During any rotational movement, it is stationary and does not move.

If you were to place a two dimensional data set in x-y plane, you would get the following:

some data in the xy plane

This data can be numerical data derived by functions or obtained from satellite sensors. It is nothing more than an x-y array full of data values. We can use this array of values in two ways:
  1. Create a shaded relief surface, using the values in the array as "z". This surface can be shaded using different shading algorithms, light source models or another array.
  2. Use a x-y array as the shading factor for a shaded relief surface.

a cheesy shaded surface and a cheesy shaded surface with array as shading

In the case of this web interface, we can one or both methods. The array of DEM data values creates the surface, and if chosen, the satellite derived data can be used as the shading factors.

Axis Manipulations

There are two possible axis manipulations:

  1. A rotation about the Z axis will spin the data about the "z" axis.
  2. A rotation about the X axis will tilt the data and axis configuration about the "x" axis. This rotation is towards (positive values) or away (negative values) from the user.

mtdolan@mtu.edu