[GRASS-dev] Re: [GRASS-SVN] r44252 - grass/branches/releasebranch_6_4/imagery/i.atcorr

[Markus Neteler]

On Mon, Nov 8, 2010 at 10:28 AM,  <svn_grass at osgeo.org> wrote:
...
>   grass/branches/releasebranch_6_4/imagery/i.atcorr/6s.cpp
>   grass/branches/releasebranch_6_4/imagery/i.atcorr/main.cpp
> Log:
> i.atcorr: be less verbose, fix when elevation is not given
> (merge r44250 from devbr6)
...

Just curious about this change:

> Modified: grass/branches/releasebranch_6_4/imagery/i.atcorr/main.cpp
> ===================================================================
> --- grass/branches/releasebranch_6_4/imagery/i.atcorr/main.cpp  2010-11-08 09:27:08 UTC (rev 44251)
> +++ grass/branches/releasebranch_6_4/imagery/i.atcorr/main.cpp  2010-11-08 09:28:04 UTC (rev 44252)
...
> @@ -331,7 +330,8 @@
>                G_set_f_null_value(&buf[col], 1);
>                continue;
>            }
> -           alt[col] /= 1000.0f; /* converting to km from input which should be in meter */
> +           if (ialt_fd >= 0)
> +               alt[col] /= 1000.0f; /* converting to km from input which should be in meter */
>
>             /* check if both maps are active and if whether any value has changed */
>             if((ialt_fd >= 0) && (ivis_fd >= 0) && ((prev_vis != vis[col]) || (prev_alt != alt[col])))

If no elevation is available, perhaps better issue a warning/fatal error?
I am not very familiar with this code so I dunno but in general
performing atmospheric
correction without DEM can lead to nonsense. But perhaps my observation is
not applicable in this code chunk.

Markus