[GRASS-dev] r.watershed flow option

[Hamish]

Helena wrote:
> Maybe I am overlooking it but the man
> page for r.watershed does not say what units 
> the option "flow" should be in - I am guessing it is
> fraction of 1 (or percent given as decimal - e.g. 50% will
> be 0.5)
> 
> so should flow amount  read as fraction or something
> like that, so that if all rainfall turns to runoff = 1
> only 50% rainfall turns to runoff (rest is captured by
> vegetation or infiltrates) = 0.5

I don't think so, it seems to be reading the map as CELL, so
giving it input data in the range of 0.0-1.0 would be binary.


ram/init_vars.c

/* read flow accumulation from input map flow: amount of overland flow per cell */

 opened with
G_open_cell_old(run_name, "")
 read with
G_get_c_raster_row()
 into
G_allocate_cell_buf()

value set as
   wat[SEG_INDEX(wat_seg, r, c)] = buf[c];


after that I lose track of what it does.. maybe it is setting up
initial conditions??


> should some explanation go into manual?

once we know the answer, sure :)



Hamish