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Geological 3D Mapping

Some customers, often geologists, have requested the ability to create map projects involving multiple 3D surfaces - typically using multiple Digital Elevation Models or other grid data. This could involve, for example, an aerial image draped on a 3D DEM surface topology layer with other layers perhaps representing underground bedrock, hydrology, infrastructure, or modelled hydrocarbon and mineral deposits. Recently implemented support for "geological" 3D maps enables using multiple, vertically spaced DEMs and other layers in the same project.

The features to create geological 3D maps reside in the layer properties control, so readily available to users of the GIS Editor and developers working with the GIS Developer Kernel.

In most situations, the steps to create geological 3D maps are as follows.

1. For one DEM layer, select in its layer properties the 3D option "Treat layer as Elevation Model (DEM)". Most often, this layer represents the surface topology. An aerial image or other layer(s) can be draped on this DEM layer and rendered in 3D.
2. In the 3D control panel for the Elevation Model (DEM) layer, set the "Wall" property to "off" (default setting is "texture").
3. For other layers in the project (DEM and other), select in layer properties the 3D option "Treat layer as 3D Objects".

Explanations:

• General advice is to: 
  1. apply ”3D -> Treat layer as Elevation Model (DEM)” option only to the DEM layer over which another layer(s) will be draped (typically this is the surface topology layer) and
  2. select “3D -> Treat layer as 3D Objects” option for all other DEM or grid layers.
• If the "Treat as Elevation Model (DEM)" option is selected for multiple DEM layers, the Z value for each X,Y position is taken from the last drawn (i.e., top most) such DEM layer and draping of other layer(s) is performed on that DEM.
• The walls of any DEM layer with "Treat layer as Elevation Model (DEM)" option selected, if drawn, will cover surfaces existing below that layer. Disable wall drawing by setting this DEM layer's “Wall” property to “off”.
• The "Treat layer as 3D Objects” option is used to separate multiple DEM surfaces in a project.
• A DEM layer treated as 3D Objects is displayed as a surface without walls. This ensures an aerial image or other layers will not be draped on this surface.
• The vertical level of each layer is managed by adjusting its 3D FalseZ property, such as to reflect true vertical distances or optimized presentation.
• If necessary, adjust the “Base plane” level or disable “Base plane” drawing in the 3D control panel.

Aerial image draped on a DEM surface layer. DEM walls cover layers beneath.
 

Draped Elevation Model with wall drawing turned off and a below-surface grid layer.
 

DEM or 2D layers can also be above the surface Elevation Model layer, such as to model air pollution or other atmospheric data.

2D pixel layer rendered above the draped DEM surface layer.