importing DEM, Landsat data

[de584438 at longs.lance.colostate.edu]

> 
> I will importing both DEM and Landsat data into Grass soon, but based
> on what I know so far, I see a problem. That is, the commands I have
> know about (m.dem.extract, i.tape.tm) assume the data is coming from tape.
> The data I have and will be getting are already on disk/diskette.
> The LandSat diskette, for example, has separate disk files for each of the
> bands and a separate header file as well. Are these files in need of
> processing to convert to Grass raster format, or are they already in that
> format? How do i proceed to import such files into a Grass database?
> 
> The DEM files are USGS dems and exist as indivual ascii files. Again, the
> m.dem.extract assumes it's reading a tpe not a disk file. How to proceed?
> 

	you have several options dependent upon what type of DEM data you have.  

		If you have 7 1/2 min quads and the data is on disk as
dem format, ie
		with the headers and all.  Remove the header and use
m.dem.extract.  When it asks 
		for the device specify the full path name to the file. 
I have done this numerous times.  

		If you have 3 arc second usgs dem data it is really dma
data.  use m.dmaUSGSread and
		m.rot90 and r.in.ll to bring this stuff in.  Again, you
can specify pathname and file.

		If your data is indeed ascii, ie just the numbers, look
at r.in.ascii.  You supply a header
		file prepended to the data that specifies
region,col,rows,and resolution.  then r.in.ascii 
		will bring it in.


good luck

dan