Image resolution

[Jacob Delfos]

Lluís,

If you are using PNG, it is possible you only get 256 colours. Put these statements in your mapfile (comment out your existing outputformat and imagetype, if any), and check whether it gets any better:

OUTPUTFORMAT
  NAME jpeg
  DRIVER "GD/JPEG"
  MIMETYPE "image/jpeg"
  IMAGEMODE RGB
  EXTENSION "jpg"
  FORMATOPTION "QUALITY=80" 
END

IMAGETYPE jpeg

When I mentioned about changing the image size, I meant in your template. Do you have an "<image" statement around your [img] parameter, and if so, is the width of it the same as the mapimage in your mapfile?

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



-----Original Message-----
From: Lluís Garcia i Mestres [mailto:lluisgm at gmail.com] 
Sent: 19 April 2005 15:40
To: Jacob Delfos
Cc: MAPSERVER-USERS at lists.umn.edu
Subject: Re: [UMN_MAPSERVER-USERS] Image resolution

I didn´t change the image size, it's the original from the tfw. My tif
is a composition of 6 RGB and is displayed as a raster layer in the
correct position. The resolution of the image and the map is the
same:72 dpi.

The output format is png, and I think the problem should be there.

Lluís


On 4/19/05, Jacob Delfos <jacob.delfos at maunsell.com> wrote:
> Is your map-image being displayed at its normal resolution, or did you
> specify a size for the image ( <img width=x height=x ) which does not match
> your map-image size?
> Or are you by any chance using GIF as an output format? Or another format
> that is not rgb? Sometimes using indexed colour (8bit, 256 colours) can
> create the illusion of reduced resolution, because pixels of similar colour
> get merged.
>  
> Regards,
>  
> Jacob
>  
>  
>  
> -----Original Message-----
> From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
> Behalf Of Lluís Garcia i Mestres
> Sent: 18 April 2005 22:04
> To: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: [UMN_MAPSERVER-USERS] Image resolution
>  
> Hi 
>  
> I'm working with a tif file of 0,5 meter per pixel. I don't know why,
> when I check this tif out of mapserver the quality is greater than
> when I display it in my mapserver application. I´ve try with different
> resolution in the map file but the quality is still the same.
>  
> Thanks
>  
> Lluís
>
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