[GRASS5] [bug #2061] (grass) r.los needs FP update

[Glynn Clements]

Markus Neteler wrote:

> > > Subject: r.los needs FP update
> > > 
> > > grass binary for platform: Compiled from Sources
> > > 
> > > After inspection of the source code (due to unsatisfying results)
> > > it seems that 'r.los' only works with CELL elevation data:
> > > 
> > > src/raster/r.los/cmd/main.c:
> > >          /*  allocate buffer space for row-io to layer           */
> > >          cell = G_allocate_cell_buf();
> > >          /*      open elevation overlay file for reading         */
> > >          old = G_open_cell_old (elev_layer, old_mapset);
> > > etc.
> > > 
> > > The module should be fixed to also accept FCELL/DCELL DEMs.
> > > However, I have no clear idea how much work is needed for
> > > that as segmentation is used internally.
> > 
> > It should probably be changed to just use either FCELL or DCELL
> > internally. I don't see any reason to preserve the underlying data
> > type.
> 
> Sounds good - but the segment library (src/libes/segment/) seems
> to be limited to CELL.

That contradicts the documentation, which implies that the cells may
have arbitrary size; i.e. a cell is just "len" bytes, where "len" is
given in the call to segment_format(). Cursory examination of the code
supports the documentation.

-- 
Glynn Clements <glynn.clements at virgin.net>