[GRASS-user] r.patch, images vs coloured elevation data, aerial photo mosaic

[John Stevenson]

Hi,

I have two questions, first a specific one, secondly a more general one.

1)  I have some aerial photos that I want to mosaic.  I am able to do 
this with r.patch.  However, the photos only cover about half of the 
region.  In the remainder of the region, I would like to show a shaded 
relief map as a background to give context to the photos.  When I 
include the shaded relief map in the list to patch, it comes out as 
varying shades of red.  My question is therefore, what do I have to do 
to the shaded relief map to turn it into an 'rgb image' that I can 
include in r.patch.

2)  More generally, what is the best way of converting a good-looking 
map into a georeferenced image e.g. by converting the elevation data 
into rgb pixel colour data.  Currently I would use d.out.file then 
gdal_translate, but that is dependent on the screen resolution.

Cheers

John

-- 


Dr John Stevenson
Postdoctoral Research Associate
School of Earth, Atmospheric and Environmental Sciences
Williamson Building (Room 2.42)
University of Manchester
Manchester M13 9PL, UK
tel. +44(0)161 306 6585; fax. +44(0)161 306 9361;
john.stevenson at manchester.ac.uk