[mapserver-users] Difference in appearance between "mode=map" and WMS
Julien-Samuel Lacroix
jlacroix at mapgears.com
Mon Dec 8 13:39:17 PST 2008
Hi,
Did you try the other way around? Making the WMS request with a square BBOX?
Mapserver should return a valid image. Maybe others may help, I remember
a bug of a 1 pixel error in some cases, but I don't remember what it was
exactly.
Julien
Roger André wrote:
> Hi Julien,
>
> That makes sense, but it doesn't work. I modified my mapfile so that I
> now generate a 20_deg x 20_deg tile that is 600_pixels x 600_pixels. If
> I georeference that image using the extents, I still get incorrect
> placement. Maybe if I choose an output projection which always has
> square pixels, like spherical mercator (?) this will work. I'll give it
> a shot.
>
> Is there any way to give a WMS request via mapscript and NOT go through CGI?
>
> Roger
> --
>
>
>
> On Mon, Dec 8, 2008 at 12:25 PM, Julien-Samuel Lacroix
> <jlacroix at mapgears.com <mailto:jlacroix at mapgears.com>> wrote:
>
> Hi,
>
> I guess would be that the WMS use non-square pixels. So if your BBOX
> x/y (rectangle in your case) doesn't match you WIDTH/HEIGHT ratio
> (square in your case) the map will appear stretched. MapServer will
> actually stretch the map to fit the extent in the WIDTH/HEIGHT.
>
> The mode=map don't do that. If your extent doesn't have the same
> ratio, it adds some degree in your extent to fit the size.
>
> Make sure your BBOX and EXTENT are a square in your requests and retry
>
>
> Julien
>
> Roger André wrote:
>
> Hi All,
>
> I think I'm having an instance of cranial flatulation, but maybe
> not. Hopefully you can set me straight.
>
> I need to create an image with Mapserver using mapscript that I
> can then georeference manually and use in another application.
> It needs to look exactly the same as the image I can already
> generate via a WMS call that looks like this:
>
> http://localhost/cgi-bin/mapserv?map=/var/www/mapfiles/hydro/hydro.map
> &SERVICE=WMS
> &version=%221.1.1%22
> &REQUEST=GetMap
> &LAYERS=imagery
> &STYLES=&BBOX=-125,39,-108,54
> &WIDTH=600
> &HEIGHT=600
> &FORMAT=png
> &SRS=epsg:4326
>
> I'm testing my mapscript parameters using a simple "mode=map"
> call to Mapserver, and the results I'm getting so far don't
> match the appearance of the WMS output at all. My mapfile has
> the following extent and projection info in it:
>
> PROJECTION
> "init=epsg:4326"
> END
>
> EXTENT -125.0 39.0 -108.0 54.0
> SIZE 600 600
>
> In addition to the mapfile projection specification, I am also
> specifying the same projection info in each of my LAYERS as well.
>
> Is it possible to do what I'm trying to accomplish here?
>
> Thanks,
>
> Roger
> --
>
>
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>
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>
> --
> Julien-Samuel Lacroix
> Mapgears
> http://www.mapgears.com/
>
>
--
Julien-Samuel Lacroix
Mapgears
http://www.mapgears.com/
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