[GRASS-dev] creating new modules

[Hamish]

Kirk Wythers wrote:

> The goal here is to write a module r.pnet. PnET is a general  
> ecosystem model that does carbon, water and nitrogen balance. It can  
> output things like gross and net primary production, net ecosystem  
> production, plant and ecosystem respiration, etc.
> 
> In it's present form PnET requires a file of vegetation parameters,  
> and a file of climate parameters (climate inputs are temporal, i.e.  
> daily time step would have one day of temps, precipitation, and solar 
> 
> radiation per line). However, on a spatial application such as this,  
> climate will vary both temporally and spatially, therefore I will  
> need a multidimensional data holder for climate inputs.
> 
> Presently the vegetation parameters are in individual files based on  
> cover type (for example, one file for oak, one file for maple, one  
> file for pine, one file for corn, etc...
> 
> I am envisioning a GRASS module that takes a input raster of land  
> cover, and for each pixel, gets the vegetation parameters associated  
> with the land cover type, gets climate data for the current time step 
> 
> (that day for example), then runs the PnET model for that pixel, then 
> writes it's output, before moving on to the next pixel.
> 
> Perhaps a good start would be to write some over simplified PnET code 
> into the "does nothing" portion of r.example and see if I can get  
> anything working?


How complicated is the PnET model? e.g. can you write a prototype using
r.mapcalc or a series of r.mapcalc commands? If the model is relatively
simple, that would be my first step.



Hamish