[mapserver-users] Re: Use of palette file: Problems with changingcolors when tiling

[Steve Lime]

Correct. My palette creation process has been to:

1) create a master image that shows as many possible rendering outputs as possible as a 24-bit PNG. 

2) use a tool to reduce the colors in that image to the desired number and create a 8-bit file. In my case
I use PhotoShop and produce a gif. Here's a link to the one I used for our rec. compass app but after 
color reduction to 128 colors.

  http://maps.dnr.state.mn.us/compass/remove/compass_color_master.gif 

3) extract a palette from the 8-bit image. I wrote a little perl script that processes gdalinfo output.

4) my outputformat block is like so:

  OUTPUTFORMAT
    NAME png
    DRIVER "AGG/PNG"
    MIMETYPE "image/png"
    IMAGEMODE RGB
    EXTENSION "png"
    FORMATOPTION "INTERLACE=OFF"
    FORMATOPTION "PALETTE_FORCE=TRUE"
    FORMATOPTION "PALETTE=/mapserver/compass/compass.palette"
  END
 
I've not had problems with this method...

It's possible there's a bug but it's going to be difficult to fix without a good test case.

Steve

>>> On 11/6/2009 at 9:52 AM, in message
<a4cd3760911060752i609ad757g9872b8ff5a9b5c27 at mail.gmail.com>, Espen Isaksen
<espen.isaksen at gmail.com> wrote:
> Sorry, this still creates trouble. And you have omitted
> 
> FORMATOPTION 	 "PALETTE_FORCE=TRUE"
> 
> on this one. That means it does not use the palette file right?
> 
> Espen
> 
> 
> 2009/11/6 Stephen Woodbridge <woodbri at swoodbridge.com>:
>> Espen,
>>
>> Try using this:
>>
>>    OUTPUTFORMAT
>>        NAME agg
>>        DRIVER "AGG/PNG"
>>        MIMETYPE "image/png"
>>        IMAGEMODE RGB
>>        FORMATOPTION "INTERLACE=false"
>>        FORMATOPTION "QUANTIZE_FORCE=ON"
>>        FORMATOPTION "QUANTIZE_DITHER=OFF"
>>        FORMATOPTION "QUANTIZE_COLORS=256"
>>        FORMATOPTION "PALETTE=/data/maps/palette.txt"
>>    END
>>
>> And see if it does what you want. Also note that I use "ON" and note "TRUE"
>> as the value of "QUANTIZE_FORCE", but I'm not sure if the matters or not.
>>
>> -Steve
>>
>> Espen Isaksen wrote:
>>>
>>> Yes, that is what we have been doing all along. I guess I never should
>>> have mentioned our testing with putting lots of colors in the palette
>>> file, as it just confuses people :-)
>>>
>>> So forget our testing, we have only put the colors we use in the
>>> mapfile once in the palette file(attached in the first mail), and the
>>> error in the color is like on the map I attached(first mail).
>>>
>>> Espen
>>>
>>>
>>>
>>> 2009/11/6 Thomas Bonfort <thomas.bonfort at camptocamp.com>:
>>>>
>>>> Stephen Woodbridge replied to this thread, and gave the correct usage
>>>> of the palette file: set the same colors in your palette file as in
>>>> your mapfile.
>>>>
>>>> regards,
>>>>
>>>> thomas
>>>>
>>>> www.camptocamp.com 
>>>> +33 5 16 57 01 02
>>>>
>>>>
>>>>
>>>> On Fri, Nov 6, 2009 at 14:24, Espen Isaksen <espen.isaksen at gmail.com>
>>>> wrote:
>>>>>
>>>>> Justed wanted to bring this question into attention again since we did
>>>>> not get a solution to the problem, and we have not found one either.
>>>>>
>>>>> Could this possibly be a bug in Mapserver? Should we report it?
>>>>>
>>>>> Espen
>>>>>
>>>>>
>>>>>
>>>>> 2009/10/28 Espen Isaksen <espen.isaksen at gmail.com>:
>>>>>>
>>>>>> Hi!
>>>>>>
>>>>>> We are testing out using a palette file in our outputformat to
>>>>>> decrease file size in the png output. Most of the time this works
>>>>>> great, but some times when we are tiling the data we get some errors.
>>>>>> The color seem to shift to a similar color from one tile to another.
>>>>>>
>>>>>> We have added the colors we use in the map file in the palette.txt
>>>>>> file. The documentation says it needs 256 colors in the map file, but
>>>>>> we do not use that many colors right now. (we tried adding the same
>>>>>> color more than one time, but that created other problems....)
>>>>>>
>>>>>> I have attached a png file showing the problem across a lake. The
>>>>>> color on the right side is the correct color and the color we have
>>>>>> added to the palette file. The color on the left side of the lake is
>>>>>> not something we have set.
>>>>>>
>>>>>> I have also added the palette.txt file and the outputformat we use is
>>>>>> this:
>>>>>>
>>>>>>        OUTPUTFORMAT
>>>>>>                       NAME             "png"
>>>>>>                       DRIVER           "AGG/PNG"
>>>>>>                       MIMETYPE         "image/png"
>>>>>>                       IMAGEMODE        "rgb"
>>>>>>                       EXTENSION        "png"
>>>>>>                       FORMATOPTION     "PALETTE_FORCE=TRUE"
>>>>>>                       FORMATOPTION     "PALETTE=/data/maps/palette.txt"
>>>>>>                END
>>>>>>
>>>>>> Does anybody know why this happens in Mapserver and how to fix it?
>>>>>>
>>>>>> Espen
>>>>>>
>>>>> _______________________________________________
>>>>> mapserver-users mailing list
>>>>> mapserver-users at lists.osgeo.org 
>>>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users 
>>>>>
>>> _______________________________________________
>>> mapserver-users mailing list
>>> mapserver-users at lists.osgeo.org 
>>> http://lists.osgeo.org/mailman/listinfo/mapserver-users 
>>
>>
> _______________________________________________
> mapserver-users mailing list
> mapserver-users at lists.osgeo.org 
> http://lists.osgeo.org/mailman/listinfo/mapserver-users