New to grass -- a couple of questions

Stephen Griffiths griffiths at
Thu Jun 1 18:47:17 EDT 2000

Hi all,

I am new to Grass so please forgive to simple nature of my questions.

I have been trying to read my DEMs and Ortho images into grass.  I have
used "".  This has worked fine if the data is in an 8bit
unsigned binary format -- thats ok for the image, but not the DEM.  How
can I read the DEM in as 16bit unsigned or even better 32bit float?  My
DEM's are all in 32bit float flat binary raster format.  I really do not
want to convert them to some other format first.

It there a way to have grass generate a null value mask raster given a
closed polygon (vector) such that outside the poly the values are null,
while inside the poly the values are 1?  Then could I multiply the mask
raster with the DEM (image) raster to null the result outside the
project bounds?  Nulling the raster outside the bounding polygon would
help out greatly.

Can grass mosaic multiply images together?  How does grass do this?
Does it use a seam line defined by the user, or some other method?

Finally, I have tried running NVIZ put had no success.  I have a RH6.0
linux box with a 16bit color depth display.  I can increase the color
depth to 24bits if I reduce the screen res.  Is there something I am

Thanks in advance for any help.

Stephen Griffiths
Spectral Imaging Solutions Inc.

Live life now, procrastinate later.

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