Add Topography

Add topography from a Digital Elevation Model (DEM) is used to update the topography of the data.

To do this, first select the data, processing or model selection node in the workspace explorer and then select Add (Elevation Model) either on the Data Processing or Inversion ribbon.

• If a data node was selected, all existing processing nodes on that data node will be updated. Any processing nodes added to the data node later, will need to have the topograpy added again.
   
• If a processing node was selected, only that one node will be updated. If the GPS position of a processing node later is reprocessed, this will overwrite the topography.
   
• If a model selection node was selected only the models in that model selection will be affected. This used to work differently. It used to also affected all models in the databases from which the model selection was made and any new model selection made from the same models, but that is no longer the case.

There are two ways to add topography from a DEM. It can be done with a DEM from External Grid File or with a DEM node from Workspace.

• When done from an external (surfer) grid file, both the path to the grid file and the coordinate system of the grid file must be given.
   
• When done from a DEM node (AddDEMNode), the coordinate system is already know, so it is enough to select the DEM node from the dropdown.

In either case the grid will be loaded and its extend can be compared with the extend of the data points in the lower part of the window.

There are two ways to handle data points not defined in the grid, they can left unchanged or set to 0 with the dropdown. The later option is often relevant near sea level.