Help with USGS DEM files

Started by batzilla, January 01, 2007, 02:18:54 am

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batzilla

Hi all- I am a Mac user and I love Terragen 2 and was hoping someone could tell me how to use USGS DEM files. I understand you need some kind of converter? I also see that if I were on a PC this would be no problem but being on a Mac, I can't find any program that'll do what I THINK I need.

Total newbie here. BTW, i'm using a PPC Mac and not the newer Intel machine.

Also, any good links to where I can download the USGS files? Are they expensive? Any particular type of file I should be aware of?

Thanks for any insight!

batzilla

WOW TIM!! Thanks for the links!

I think I may have found a program similiar to 3DEM for *classic* OS 9 running on my OSX. If it works out i'll report back here for others to know.

I really appreciate you taking the time to help out. I hope I can return the favor someday!

FrankThomas

Here's a link to a pretty good source of DEM data (it's the one I use most of the time)

It'll download the files in .tar.gz format - won't cost anything for slow downloads but you can buy faster downloads if you want to

http://data.geocomm.com/

PatrickH

I use this site to get real-world heightfeild info:
http://seamless.usgs.gov/website/seamless/viewer.php

You can download selected areas (really cool because there's no stiching involved- unless you want a larger chunk of land- there's a limit on the area you can select).  You can download in NED elevation data in GeoTIFF, ArcGRID, and BIL?, and Gridfloat formats.  Not sure which app you could use to convert to .ter on your Mac, but maybe there's something.

Patrick

FrankThomas

am I the only one who just can't get on with the seamless site ? I dunno - must be something about the interface just leaves me cold :)

FrankThomas

yup - I download as .bil which 3DEM is quite happy with

PatrickH

It took a little while to get used to the seamless site.  The tuts posted above helped.  Now i love it but maybe there's something better that i don't know about.  I just love that you can select whatecer area and not have to worry about stitching.  Are there other sites that let you just select the area you want like the seamless site does?
Patrick

Oshyan

The seamless site is really one of the best interfaces to worldwide DEM data that exists. I know, I've looked. But it does take some getting used to. The thing of it is there's tremendous power, flexibility and access to data there. So it can be overwhelming. If you can just find a basic path through to the files you want then you can follow that in the future and it should be fairly easy. The main thing is to determine what data type you need, which will depend on the applications available to you. I do strongly encourage buying Global Mapper if you are serious about using DEM's. It's pricey, but for the money I don't think you can buy any other app that better supports a variety of real-world raster and vector formats, including virtually every known DEM format and direct Terragen .ter export as well.

- Oshyan