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Topic: Getting DEM Digital Elevation Model Maps
Replies: 1   Last Post: Oct 12, 2011 6:27 AM

 Messages: [ Previous | Next ]
 Oliver Posts: 30 Registered: 4/14/09
Getting DEM Digital Elevation Model Maps
Posted: Oct 12, 2011 6:18 AM

Hi All,

I'm trying to get some digital elevation maps of the area round Los Angeles and Phoenix, Az.

I've tried sources from links on this page, but I can't find any good data. I keep getting redirects to old servers that say this map data is obsolete. It's driving me nuts!
(http://www.mathworks.co.uk/support/tech-notes/2100/2101.html)

I found some data from
http://store.usgs.gov/

but when trying to read it with....
----------
[Z,refvec] = usgsdem('sf_south.dem',1);
----------

i get...
----------
??? Error using ==> usgsdem>usgsdemf at 84
Ground planimetric coordinates not in arc-seconds. Try USGS24KDEM
----------

So i try...
----------
[Z,refvec] = usgs24kdem('sf_south.dem',1)
----------

i get Z and refvec output as 1393x1111 matrices,
tried this....

----------
mapshow(Z,refvec)
??? Error using ==> checkrefmat at 23
Function MAPSHOW expected its second input argument, R,
to have size [3,2].
----------
usgs24kdem must be wrong as refvec is only meant to be [3,2].

and using imagesc(Z) it's just a matrix with a gentile gradient going down the Cols (37.7505 to 37.6245) the Rows are all the same values.

Any ideas or help where I can just get some simple elevation data?? Lat Long Height

Date Subject Author
10/12/11 Oliver
10/12/11 Oliver