[mapserver-users] anti-aliasing (was differing image size with different mapserver versions)

[Richard Greenwood]

Oops - typo there, reducing the colors from 256 to *125* reduced the image
size by about 15%.

On Tue, May 18, 2021 at 12:11 PM Richard Greenwood <
richard.greenwood at gmail.com> wrote:

> Bob - I think GD was quite unpopular with the developers. Thomas Bonfort
> was pretty adamant about removing it. I'm hoping that there may be options
> in AGG.
>
> Seth - FORMATOPTION "COMPRESSION=9" only reduced the size by about 3% in
> my lines and text test case.
>
> Even - the default AGG/PNG8 has QUANTIZE_FORCE=on and QUANTIZE_COLORS=256.
> I think I remember you saying somewhere that reducing the number of colors
> mostly just reduced the pallet size and that's pretty much what I see. e.g.
> reducing the pallet from 256 to 15 colors reduces the image size by about
> 15% in my lines and text test.
>
> Thanks all for the suggestions.
> Rich
>
>
> On Tue, May 18, 2021 at 11:49 AM Even Rouault <even.rouault at spatialys.com>
> wrote:
>
>> Forcing paletted images using QUANTIZE_FORCE=on and decreasing the number of colors with QUANTIZE_COLORS can also help:
>>
>>  FORMATOPTION "QUANTIZE_FORCE=on"
>>  FORMATOPTION "QUANTIZE_COLORS=200"
>>
>> Le 18/05/2021 à 19:30, Seth G a écrit :
>>
>> I've not used it but the following might help for the AGG/PNG driver:
>>
>> FORMATOPTION "COMPRESSION=9"
>>
>> https://mapserver.org/mapfile/outputformat.html
>>
>> The default is 6.
>>
>> --
>> web:http://geographika.co.uk
>> twitter: @geographika
>>
>>
>> On Tue, May 18, 2021, at 7:16 PM, Basques, Bob (CI-StPaul) wrote:
>>
>> All,
>>
>>
>>
>> I know the GD stuff has been a long running conversation in the MapServer
>> realm, but does this indicate that maybe discussing something on adding GD
>> back in might be prudent?  Or are there methods to get down to these
>> previous files sizes with the newer approaches?
>>
>>
>>
>> I have the same concerns related to image size from the performance side,
>> and running on Mobile in our case.
>>
>>
>>
>> Bobb
>>
>>
>>
>>
>>
>> *From: *mapserver-users <mapserver-users-bounces at lists.osgeo.org>
>> <mapserver-users-bounces at lists.osgeo.org> on behalf of Richard Greenwood
>> <richard.greenwood at gmail.com> <richard.greenwood at gmail.com>
>> *Date: *Tuesday, May 18, 2021 at 11:50 AM
>> *To: *"mapserver-users at lists.osgeo.org" <mapserver-users at lists.osgeo.org>
>> <mapserver-users at lists.osgeo.org> <mapserver-users at lists.osgeo.org>
>> *Subject: *[mapserver-users] anti-aliasing (was differing image size
>> with different mapserver versions)
>>
>>
>>
>> *Think Before You Click: *This email originated *outside *our
>> organization.
>>
>>
>>
>> Thanks to several helpful replies to my previous thread I know that the
>> increased image size between MapServer 6 with the GD driver and MapServer 7
>> with the AGG driver is due to differences in anti-aliasing (and lack of) in
>> the two drivers. (AGG features anti-aliasing and sub-pixel resolution
>> <https://en.wikipedia.org/wiki/Anti-Grain_Geometry>).
>>
>>
>>
>> Gamma setting from 0-1 affects the size of a filled polygon layer by a
>> factor of almost 3x. But gamma has no effect on text, lines, and polygon
>> outlines. So images comprised of these types of features are approximately
>> 2x larger with the AGG/PNG8 driver than with the GD/GIF driver.
>>
>>
>>
>> Where else should I be looking to reduce my images sizes? I serve rural
>> areas with poor internet so in my case, smaller image sizes are more
>> important than higher quality images.
>>
>>
>>
>> Thanks,
>>
>> Rich
>>
>>
>>
>> --
>>
>>
>> Richard W. Greenwood, PLS
>> www.greenwoodmap.com
>>
>>
>> _______________________________________________
>> mapserver-users mailing list
>> mapserver-users at lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
>>
>>
>> _______________________________________________
>> mapserver-users mailing listmapserver-users at lists.osgeo.orghttps://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
>> -- http://www.spatialys.com
>> My software is free, but my time generally not.
>>
>> _______________________________________________
>> mapserver-users mailing list
>> mapserver-users at lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/mapserver-users
>>
>
>
> --
> Richard W. Greenwood, PLS
> www.greenwoodmap.com
>


-- 
Richard W. Greenwood, PLS
www.greenwoodmap.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/mapserver-users/attachments/20210518/bbe9c61d/attachment.html>