Import a 10m DEM with vertical units in decimeters

Summary

The normal process of importing a 10m DEM with vertical units in decimeters does not produce the proper floating point grid in ArcView. This article shows how to convert the DEM file. This process requires the use of ArcView's Spatial Analyst and ModelBuilder extensions.

Procedure

1. Make sure you have the Spatial Analyst and ModelBuilder extensions turned on in your project.
2. With your view active, click Model > Start ModelBuilder.
3. Select Add Process > Data Conversion > DEM to GRID.
4. Click Next on the DEM Conversion window that pops up.
5. Select the DEM file to convert.
6. Click Next.
7. Click the Classify button in the Define Legend Table.
8. Change the number of classes to at least six and ensure that there are a minimum of three decimal places.
9. Click Next.
10. Select the desired color scheme for the output.
11. Click Next.
12. Select the extent of the output theme.
13. Click Next.
14. Set the cell size of the output theme.
    
    

    Note:
    Make sure the map units are set to Meters if you wish to have the vertical units converted to meters.

    
    
15. Click Next.
16. Document the data.
    
    

    Note:
    It is a good idea to also include the location from where the data was downloaded (in the Reference URLs tab), as well as any other comments about the data.  This may be useful in the future.

    
    
17. Click Next.
18. Name the output theme.
    
    

    Note:
    The first box is for naming the output grid as it appears in your view.  The second box is for giving a name to the data that is stored on your hard drive.

    
    
19. Click Finish.
20. Select Run from the Model menu or click the Run Model button.
    
    
21. Click OK and let the process run after you tell it where to store a new folder that would serve as your workspace and give the model that you are running a name.
22. Make sure the legend values contain the proper floating values since the newly converted DEM will appear in your view.
    
    

    Note:
    Incorrect vertical values were originally discovered when the same DEM was converted to a lattice in Workstation ArcInfo using the DEMLATTICE command.