Need Help MicroDem files for Tranz Dem


New member
I downloaded 2 Geotif NED 1 Arc second files for the United States they were generated from the seamless servor as a single selection of territory.
I merged them in MicroDem and than tried to load into TranzDem. I get the following error:

Dem grid not in Meters.

I went back into MiroDem and selected the the Overlay menu and went to grid options.

One col is this

I checked UTM

UTM grid interval (m) 20000
Lat/Long grid interval (O)

For the Label Grid option I selected UTM.

Info indicates Dem Height is in Meters.

File saved as MD DEM by Microdem. Am using Microdem 10.0 Alpha Build 2006.8.30.2

Transdem verision is

Error still occuring so I am stumped.

I don't know what TransDem expects. The error sounds like it's looking for input with a rectangular meter grid. The 1 arc sec is a long/lat grid which is not a rectangular meter grid. Changing the overlay grid in MD does not change the DEM data - it only changes the coordinate display in MD. To change the DEM requires resampling the data. MD can do this if that is required for TransDem. On new versions of MD (8 and abv IIRC) you access it thru the "Reinterpolate, UTM" option on the save file menu. Older versions used the resample option on the in/out or data manipulation menu. Geophil can probably walk you thru this if needed.

Bob Pearson
TransDEM can read NED DEMs in GeoTiff format. The NEDs have lat/long coordinates.

The normal procedure with two DEMs would be to open the first NED .tif in TransDEM which will automatically convert to UTM, then save the converted DEM. TransDEM always saves in MicroDEM format.

Repeat with the second DEM, and also save it.

Use the TransDEM "Add DEM" function to merge the first NED DEM, converted and saved before, into the second DEM. Save the merged result.

Hence, there is no need for MicroDEM for DEM merging.

Nevertheless you can do it in MicroDEM if you want to. You have to explicitly convert the DEM to UTM in MicroDEM, a step taken by TransDEM implicitly during the DEM file opening phase.

(BTW, the upgrade to TransDEM 1.2 is free, a few bugs have been fixed since

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...from my perch...

:cool: If you have TransDEM, everything else is redundant...

TransDEM, has it all, and since you paid for the program, you have all the tools needed!