[GRASS5] Re: d.his r.his question
glynn.clements at virgin.net
Wed Dec 12 12:40:33 EST 2001
Eric G. Miller wrote:
> > > > > I am actaully writing with a question about d.his (and r.his). In the
> > > > > past I used a modified version of d.his to create color shaded relief
> > > > > maps. In other words I fused a color raster (h_map) with a grey
> > > > > sun-illuminated raster (i_map). The new r.his seems to be (correctly)
> > > > > designed for imagery.
> > >
> > > Treating colour images as a single raster layer with R*G*B distinct
> > > categories is something of a kludge. In the absence of vector-valued
> > > cell maps (i.e. band-interleaved-by-pixel), the next best thing (IMHO)
> > > is separate R,G,B maps (effectively band-sequential).
> > >
> > > I'm having second thoughts about whether r.his and r.composite should
> > > have separate arguments for each channel, though. It might be better
> > > to just have input=/output= and require that the bands are called
> > > foo.r, foo.g and foo.b.
> > ... that's a good suggestions which reduces typing efforts.
> > eventually just:
> > input=name [prefix=name]
> > if !prefix
> > prefix=input
> > [...]
> Umm, wouldn't imagery groups work? Already set-up for specifying the
> RGB bands...
Probably. I wasn't familiar with imagery groups when I wrote this
stuff. Actually, I'm still not familiar with them. If that's deemed to
be the right way to go, I'll look into it.
However: should r.composite be retained? E.g. for the benefit of users
who aren't familiar with imagery groups, and are looking for an
r.<something> command to process their raster maps.
Glynn Clements <glynn.clements at virgin.net>
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