Creating a Surface

Share:

After loading your point elevation layer (e.g. from a DEM), you can display it as a surface. All of Maptitude’s surface operations are on the Tools->Surface Analysis sub-menu. Select 3d Map from this sub-menu to display the Create 3D View dialog box:

The Create 3d View with one 3d layer defined

Press the green ‘+’ button to set the 3d layer, or the ‘tools’ button to edit an existing layer. This will display the following dialog box:

Adding a 3d surface layer

The radio button along the top allows you to select the 3d layer type. As well as a 3d surface, it is possible to add models (i.e. buildings) and building footprints.

The surface will be drawn as a 3d surface with an image layer. Set the image layer by selecting the current map view.

For the surface, select the point elevation layer (Grid Layer), the layer’s elevation field (Elevation), and the units for this field. The dialog box should now look something like the image above.

Back on the Create 3D View dialog box, the Background tab can be used to select any background or sky effects. We will ignore these for now. Select the Options tab:

Setting the elevation exaggeration factor

Here you can set the lighting and fog parameters. We will use the default lighting and not use any fog. By moving the light source (i.e. by changing the time and day), it is possible to move the surface shadows and bring out different subtle variations. Fog can also be used to hide distant objects such as the edge of the surface. Both effects can be combined if you are trying to visualize a landscape.

We will, however, change the Elevation Exaggeration Factor. Due to the way the human eye works, surfaces tend to look flatter on the computer screen or on paper, than they do in reality. The solution is to apply a deliberate vertical exaggeration. This is partly a personal choice and may require some experimentation. Here we set the Exaggeration Factor to 2.0, i.e. all elevations are multiplied by 2.

Press OK to create the surface. This may take some time if your elevation layer contains a lot of data points. This is a good reason to limit the extents and/or horizontal resolution of your elevation layer.

Here is the resulting surface:

The initial view of the new surface. Colors are taken from the original map view.

The tools in the top right corner allow you to navigate the surface, by rotating it, etc. Alternatively you can use the top eight buttons on the 3d Toolbox (displayed by selecting 3d Toolbox on the Surface Analysis sub-menu):

The 3d Surface Toolbox

The imagery for the surface is the same imagery as the source map. Hence most of it is colored as per the source elevation layer (green for low elevation through to magenta for high elevation). Overlying map text (eg. Texas) is also painted on to the surface. Generally you should be careful to position and enable your layers, so that only the required layers are visible before creating your surface. For example, you might want to draw rivers and major roads, but not state names.

By using the navigation controls, it is possible to zoom in on an area of interest (e.g. the Guadalupe Mountains on the Texas / New Mexico border):

The surface zoomed into an area just south of Guadalupe Mountains,TX (magenta). Click for larger view.

Note that some subtle surface features are visible in the foreground, although the bright green colors do not aid with the visibility of these features. If required, careful color choice and light positioning should help to bring these features out.

Leave a Reply

 

 

 

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code class="" title="" data-url=""> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong> <pre class="" title="" data-url=""> <span class="" title="" data-url="">