[GRASSLIST:118] Re: making a "true-color" landsat composite

[Dylan Beaudette]

Ian,

Thanks for the pointers. In the past, I was not performing any "enhancements" 
to the landsat scenes as there were so many of them, and they looked good 
enough. However with Markus' latest script, I think that I will re-compile 
arizona! good thing that I hadn't started on Nevada yet!

Cheers,

Dylan

On Tuesday 14 March 2006 12:44 pm, Ian MacMillan wrote:
> Dylan, I am not sure if you have this problem, but you might want to
> watch out with the colors when you patch landsat tiles together.  The
> colors tend to get screwy since the the shots were each taken at
> different times of day, different days of the year, etc.  I have found
> that it is best to enhance each tile separately, then patch them
> together at the end, rather than patching all band 1's, all band 2's
> etc.  You probably already knew this, but thought I would add my two
> cents.
>
> -Ian
>
> On Mar 14, 2006, at 10:04 AM, Dylan Beaudette wrote:
> > Markus,
> >
> > Nice images!
> >
> > a couple things:
> >
> > 1. the link at the top of the page had some interesting polar plots.
> > For hard copy I found that ps.rose in the GMT suite produces excellent
> > results as well:
> > http://169.237.35.250/~dylan/NPS/day100.png
> >
> > 2. the color boost technique -- is your script available on the GRASS
> > wiki somewhere, or in the grass scripts dir in a recent CVS branch?
> >
> > This looks like it will do the trick, now the only problem is that I
> > have just put together the entire state of Arizona with the poor
> > looking imagery!
> >
> > thanks for the tips,
> >
> > Dylan
> >
> > On 3/14/06, Markus Neteler <neteler at itc.it> wrote:
> >> Dylan Beaudette wrote:
> >>> Hi everyone,
> >>>
> >>> I was working on constructing some "true color" landsat composite
> >>> images today
> >>> from bands 3,2,1 -- and came across some strange inconsistencies.
> >>> Data from
> >>> one source produces "nice" true color images:
> >>>
> >>> http://casoilresource.lawr.ucdavis.edu/drupal/node/211
> >>>
> >>> whereas, another source produces somewhat muddy true color
> >>> composites. I tried
> >>> playing a bit with an equalized grey colormap for each band via
> >>> r.colors
> >>> color=grey.eq with the following results:
> >>>
> >>> http://casoilresource.lawr.ucdavis.edu/drupal/node/215
> >>>
> >>>
> >>> Does anyone have any tips on how to tweak color ramps for the
> >>> various bands so
> >>> as to get a better looking "true color" composite?
> >>
> >> how do you like this LANDSAT:
> >>  http://mpa.itc.it/markus/grass61/demos/
> >>  -> LANDSAT 7 color boost
> >> ?
> >>
> >> Markus
>
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-- 
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341