[GRASS-user] Raster file from ascii file and flattening Africa .... :)

[Corrado]

Dear friends,

I am a kind of advanced newbie, if that makes sense.

I have a text file of the form

coordinate x,coordinate y,cat={real number between 250 and 450}

where coordinate are expressed in latitude and longitude. The files represents 
measurements of the size of a skulls on sites all over Africa.

From it, I would like to build a raster file, 100 km by 100km.  There are 2 
problems:

1) Unfortunately,  in some 100km x 100km squares, there is one of the points 
whilst in others there are maybe 20. How do I average, so that in each square 
I only have 1 value representing the average?
 
2) How do we "flatten" Africa so that we may use 100km x 100km squares instead 
of 1 degree x 1 degree, without committing a geographical crime? What we need 
is to respect the areas ....

Best regards and apologies for the silliness of the questions.
-- 
Corrado Topi

Global Climate Change & Biodiversity Indicators
Area 18,Department of Biology
University of York, York, YO10 5YW, UK
Phone: + 44 (0) 1904 328645, E-mail: ct529 at york.ac.uk