[GRASSLIST:64] making a "true-color" landsat composite

GRASS GRASS user
1

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?

Thanks!

--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341

2

2006/3/13, Dylan Beaudette <dylan.beaudette@gmail.com>:

Hi everyone,

I was working on constructing some "true color" landsat composite images today

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?

Hi Dylan, I think i had the same issua a while ago. I got stuckand
left the issue behind, as it is a 'pet' project

Carlos Grohmann pointed me to OSSIM, but I didn't go after it, so I
can't say anything about it.

--
Paulo Marcondes = PU1/PU2PIX
-22.915 -42.229 = GG87vc (http://www.amsat.org/cgi-bin/gridconv)
Debian GNU/Linux = http://rj.debianbrasil.org = http://www.debian.org

3

Dylan, are you sure that you used 3,2,1? Could it be that another band is accidentally subbed in? If not, what I usually do with my landsat images if they look funky is to use d.histogram (or whatever that is now) to look at the color ramp. I then stretch the colors with r.recode.

An alternate method is to average bands 2 and 4 using r.mapcalc and then using that in the green channel. It tends to make 'true' color images a bit more vibrant.

Hope that helps,
Ian

On Mar 13, 2006, at 6:55 PM, 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?

Thanks!

--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341

-------------------------------------------------------------
This message has been scanned by Postini anti-virus software.

4

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?

You have to set the color range 0,255

r.colors image.red color=rules << EOF
0 black
255 white
EOF

etc for all three. The color=grey rules will "zoom" to the extents of
the data. You need to force black as 0 and white as 255.

Also, i.oif is a good tool for selecting the three bands with the
greatest spectral difference. Switch out those three in d.rgb 'til it
looks best..

Hamish

5

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

6

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@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

7

Dylan,

On Tue, Mar 14, 2006 at 10:04:52AM -0800, 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

yes, there is also some R extension for that.
I just thought to have it directly in GRASS (6.1-CVS).
Someone may change the xgraph output to d.graph for consistency,
cannot be hard (hey, maybe you?).

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?

Sure...

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!

Sorry - I had written the script three weeks ago but didn't advertise it
yet.

I have added parser support today, get it now from
http://mpa.itc.it/markus/grass61/demos/
-> i.landsat.rgb

6.1-CVS is needed as it uses a new feature of r.univar.sh.

thanks for the tips,

cheers

Markus

Dylan

On 3/14/06, Markus Neteler <neteler@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
>

--
Markus Neteler <neteler itc it> http://mpa.itc.it
ITC-irst - Centro per la Ricerca Scientifica e Tecnologica
MPBA - Predictive Models for Biol. & Environ. Data Analysis
Via Sommarive, 18 - 38050 Povo (Trento), Italy

8

Markus,

I believe the climatol R package will do rose plots.

Tom

Markus Neteler wrote:

Dylan,

On Tue, Mar 14, 2006 at 10:04:52AM -0800, 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
    
yes, there is also some R extension for that.
I just thought to have it directly in GRASS (6.1-CVS).
Someone may change the xgraph output to d.graph for consistency,
cannot be hard (hey, maybe you?).

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?
    
Sure...

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!
    
Sorry - I had written the script three weeks ago but didn't advertise it
yet.

I have added parser support today, get it now from
http://mpa.itc.it/markus/grass61/demos/
-> i.landsat.rgb

6.1-CVS is needed as it uses a new feature of r.univar.sh.

thanks for the tips,
    
cheers

Markus

Dylan

On 3/14/06, Markus Neteler <neteler@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

--
Thomas E Adams
National Weather Service
Ohio River Forecast Center
1901 South State Route 134
Wilmington, OH 45177

EMAIL: thomas.adams@noaa.gov

VOICE: 937-383-0528
FAX: 937-383-0033

9

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@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

-------------------------------------------------------------
This message has been scanned by Postini anti-virus software.

10

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@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

-------------------------------------------------------------
This message has been scanned by Postini anti-virus software.

--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341

11

Thanks again Markus:

your new i.landsat.rgb script did wonders on these images!

examples:

original made with r.composite:
http://casoilresource.lawr.ucdavis.edu/drupal/node/217

new one made with i.landsat.rgb:
http://casoilresource.lawr.ucdavis.edu/drupal/node/216

Cheers!

Dylan

On 3/14/06, Dylan Beaudette <dylan.beaudette@gmail.com> wrote:

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@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
>
> -------------------------------------------------------------
> This message has been scanned by Postini anti-virus software.

--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341