USGS NEDs?

[charland]

I'm going to try to add distant mountains to the route I'm working on. The route started as the FJGv2 and I added the ACN route and there was no problem with the old NEDs I used. When I extended the route south east from Amsterdam I had to download a new NED that would not mesh with the older NEDs even though they were all 1/3 Arc, but after I added the new terrain everything was good.

I can't open both NEDs in DEMEX at the same time because of whatever is causing them not to work together. This afternoon I went to the USGS and downloaded two NEDs to cover the entire route and had planned to make my distant mountains with them. Neither will open in DEMEX, saying there is some error in one of the fields.

I looked on Google hoping to find an older site with 1/3 arc NEDs but can't find any. Where are people getting them now?

Paul :-)

[scottb613]

Hi Paul,

Doesn't the USGS have geotiffs available again. Even with the memory constraints in DEMEX - you should be able to load two at 1/3 arcsec. I thought it loaded right out of the box - perhaps you need to run it through VT Builder?

Regards,
Scott

[eric]

Can't help with sourcing the DEM's, as I've pretty much given up on both Demex and Mosaic. As Scott mentioned, the memory issue just got to be too much of a hassle.

I've used TSRE to do distant mountains using HGT file data. It seems to work pretty well and I haven't had any white void issues.

[charland]

There's and idea, run it through VT Builder, thanks Scott, I'll give that a try.

What's a HGT file Eric?

Paul :-)

[charland]

Hi Scott,

I did download GeoTIFFs from the USGS website this afternoon, the are 1/3 arc minutes like every other GeoTIFF I've used over the years but they will not open in DEMEX. They will open in VT Builder and when I try to export them as GeoTIFFs to see if they will open in DEMEX an error occurs and I just get a big blank TIFF with no data in it.

Paul :-)

[scottb613]

Hi Paul,

Sorry the NED term confused me - I thought it was another format.

Hmm - I'll let you know if I think of anything else.

Regards,
Scott