[GRASSLIST:111] Re: making a "true-color" landsat composite

[Ian MacMillan]

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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