Difference between revisions of "HOWTO import USGS elevation data"

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== Importing USGS 1/3" NED datasets into GRASS ==
== Importing USGS 1/3" NED datasets into GRASS ==


1. Download the datasets you desire. '''''[link please]''''' They will arrive in a zip archive of a directory containing a subdirectory containing a file called w001001.adf, which is the main data file (tip: this is the biggest file).
1. Download the datasets you desire. They will arrive in a zip archive of a directory containing a subdirectory containing a file called w001001.adf, which is the main data file (tip: this is the biggest file).


2. '''Create a new GRASS location to work with the DEMs.'''
2. '''Create a new GRASS location to work with the DEMs.'''

Revision as of 01:35, 10 May 2007

The US Geological Survey offers a variety of digital elevation models through the "Seamless Distribution System. Here is an approach to working with them in GRASS.

Importing USGS 1/3" NED datasets into GRASS

1. Download the datasets you desire. They will arrive in a zip archive of a directory containing a subdirectory containing a file called w001001.adf, which is the main data file (tip: this is the biggest file).

2. Create a new GRASS location to work with the DEMs.
From a GRASS shell:

cd 18437824/18437824 (example directory names --- replace with your actual names)
r.in.gdal location=name_of_your_new_location in=w001001.adf out=dem

3. (re)Start GRASS in the new location.

4. Import additional files as needed:

r.in.gdal in=w001001.adf out=dem2
.. etc.

5. Use r.patch to combine the tiles into one continuous map, if desired.