mapimages have different hue (off-colour)

Jacob Delfos jacob.delfos at MAUNSELL.COM
Mon Jan 24 21:27:52 EST 2005


Steve,

I don't think this is related, because I'm not working in indexed colour. 
I did realise one thing I changed recently; I updated my graphics card drivers. I know that that SHOULD not have any effect on the physical image being generated, but.... it would explain why I saw this problem before with two machines where the only difference was that they had different hardware.
Is there any connection between graphic card drivers and mapserver? As far as I know, the drivers shouldn't have anything to do with that. Just that I can't think of anything else.

Tried viewing the mapimage in photoshop, but no difference. It seems like it uses a whole different library to compress to jpg. If I generate the same image from our production server, it creates a proper image. The good image is smaller in filesize than the bad image, but looks proper, and has a higher count of individual colours.


Jacob




-----Original Message-----
From: Stephen Woodbridge [mailto:woodbri at swoodbridge.com] 
Sent: 24 January 2005 22:47
To: Jacob Delfos
Cc: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] mapimages have different hue (off-colour)


What version of mapserver are you running?
Have you looked at this bug?
http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=306
Have you tried viewing it on another system, or viewed it in another 
program like photoshop?

-Steve W.

Jacob Delfos wrote:
> Hi All,
>  
> Got an interesting problem, which I hope someone recognises; My mapimage 
> has changed hue in the last weeks. I am not sure what I changed to cause 
> this. Perhaps an external program changed something about how my 
> computer creates images. However, even if I restore the gdal12.dll file 
> that I used previously (or any other of the many versions I have), my 
> image is still off-colour. It is greenish/yellowish compared to the 
> normal colour. It is still 24bit jpeg, though. But the mapimages from 
> all php_mapscript based sites that I run from this machine have suddenly 
> got this greenish tint.
>  
> I suspect it may be something about the overal system, because I once 
> noticed how different machines (a win2k desktop, and an XP laptop) 
> generated slightly differently coloured mapimages (different hue, 
> different saturation), even though both machines were installed with the 
> exact same mapserver files. I tried running the site using a browser on 
> the host and on a different machine, but both images look greenish.
>  
> Does anyone know what could affect the hue of the mapimage? Something 
> global?
>  
> regards,
>  
> Jacob
>  
>  
> JACOB DELFOS
> SPATIAL INFORMATION ANALYST
> Maunsell Australia Pty Ltd
> 629 Newcastle Street, WA 6007
> PO Box 81, WA 6902
> Leederville
> Western Australia
> ABN 20 093 846 925
>  
> Tel     + 61 8 9281 6185
> Fax    + 61 8 9281 6297
> jacob.delfos at maunsell.com <mailto:jacob.delfos at maunsell.com>
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