[GRASS5] Bug? In d.his

[Michael Barton]

Glynn,

I'm not sure I understand. D.his is simply reading 0's on greyscale (0-255)
images as NULLs on my machine. I can check to see if that's the case for
another machine.

Maybe this is what you need:

Put a shaded relief map in the Hue channel
Put a greyscale drape map (with some 0 values in it) in the Intensity
channel
Display

There will be clear/white areas where there are 0's in the greyscale drape
map.

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
Arizona State University
Tempe, AZ 85287-2402

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton



> From: Glynn Clements <glynn at gclements.plus.com>
> Date: Mon, 20 Mar 2006 13:18:54 +0000
> To: Michael Barton <michael.barton at asu.edu>
> Cc: grass developers list <grass5 at grass.itc.it>
> Subject: Re: [GRASS5] Bug? In d.his
> 
> 
> Michael Barton wrote:
> 
>> I discovered this when I tried to drape an orthophotoquad over a DEM for a
>> class presentation. There were a series of clear areas. When I displayed it
>> with d.rast, they were black. I queried them and they had values of 0, not
>> NULL. 
>> 
>> I ran r.nulls anyway, just to be sure, reassigning any NULLs back to 0 for
>> the orthophoto, making sure that it created a NULL bitmap. D.his still shows
>> areas with a value of 0 as clear, while d.rast does not.
> 
> Can you provide a recipe to reproduce this?
> 
> -- 
> Glynn Clements <glynn at gclements.plus.com>