Orthophoto basics WAS: [Mapserver-users] Raster geotiff turnsbackground yellow

[Charlton Purvis]

Before I submit my resignation to the IT world as a faithful servant
(before everyone makes me leave), I want you to know that I have enjoyed
the ride and have learned a lot.  Upgrading GD and getting MS 3.6 and
3.7 happy w/ PHP again (thanks to the upgrade) has rekindled my faith in
automation.

But any advice that I have ever given will probably best be ignored, or,
if you're inclined to find the safest route, do the opposite.  Why?
Because after hours and hours of frustration and too many copies of the
same data, I realized that my SHAPEPATH was pointing to one of my old
directories that had only a subset of my data (of COURSE that was the
data that rendered correctly), while the new orthos were off somewhere
else.  Hmm.  That might explain a few things.

Thanks to those who empathize.

Shamefully yours,

Charlton

-----Original Message-----
From: Frank Warmerdam [mailto:warmerdam at pobox.com] 
Sent: Tuesday, July 15, 2003 3:28 PM
To: Charlton Purvis
Cc: randy james; mapserver-users at lists.gis.umn.edu
Subject: Re: Orthophoto basics WAS: [Mapserver-users] Raster geotiff
turnsbackground yellow

Charlton Purvis wrote:
>> MAP
>    ...
> 
> IMAGETYPE jpeg
> 
> OUTPUTFORMAT
>   NAME jpeg
>   DRIVER "GD/JPEG"
>   MIMETYPE "image/jpeg"
>   IMAGEMODE RGBA
>   EXTENSION "jpg"
> END

Charlton,

As noted by others for GD 2.0.x you should get something at least 2.0.11
or
later.  Earlier versions have serious problems with alpha blending a few
other things.

I would also note that JPEG does not support IMAGEMODE RGBA only RGB.  I
am
not sure what will happen if you get this wrong.  Likely nothing
terrible,
just that the alpha is lost when writing out to the JPEG file, but it
might
is possible it could cause other problems.

However, I am doubtful whether the GD version or the IMAGEMODE thing are
your problem if you are getting other layers OK with this OUTPUTFORMAT
configuration.

Have you tried this map with "shp2img" and with debugging all turned on?
Do
you get any messages?
eg.

shp2img -all_debug 1 -m my.map -o out.jpg

Best regards,

-- 
---------------------------------------+--------------------------------
------
I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent