[GRASS-dev] r.in.xyz upgrade

[Volker Wichmann]

Hi,

I have upgraded r.in.xyz to allow for the following aggregate functions:
- skewness
- median
- percentile
- trimmed mean

To make this possible, I created singly linked lists for all points 
falling into a cell. I followed a suggestion of Glynn and used arrays 
instead of pointers and stored the head of each list in a raster map 
([GRASS-dev] storing pointers in CELL_TYPE maps? (from April 2007)). The 
linked lists are then used to calculate the corresponding statistics 
before binning the values.
So far we encountered no problems with this approach in our working 
group, but I'm not sure about some details. Maybe there should be some 
more checks, e.g. to prevent the index to overflow because of too many 
cells.

If you are interested I'd like to share the code. Maybe it would be best 
to send a copy to Hamish first?

Volker