[GRASS-user] Re: Need some help in converting a contour map to DEM map...

[Achim Kisseler]

> of the DEM after exagerating it.Now I am looking forward to drape an aerial
> image of the same area on the DEM that I have got. In order to do this I
> loaded the DEM map and then draped the imported aerial map (imported using
> r.in.gdal, but that single jpeg image(satimage.jpg) got imported into 3
> different maps namely satimage.red, satimage.green, satimage.blue, therefore
> is just draped only one of it on the DEM). The output view that I get seems
> okay but its too dark (black and white-- please see the attachment), though
> the original aerial image was colourful which I had imported. Why is it
> happening so?? Can any one help me with this.

Hi Nikhil,

take a look at
http://grass.fbk.eu/grass64/manuals/html64_user/imageryintro.html
it might give you a good introduction.
especially this part:

Visualizing (true) color composites
To quickly combine the first three channels to a near natural color 
image, the GRASS command d.rgb can be used or the graphical GIS manager 
(gis.m). It assigns each channel to a color which is then mixed while 
displayed. With a bit more work of tuning the grey scales of the 
channels, nearly perfect colors can be achieved. Channel histograms can 
be shown with d.histogram.

Regards,
Achim