[mapserver-users] advantages of having the map file header extent the actual bounding box instead of EXTENT -180 -90 180 90 # World

[Stephen Woodbridge]

John,

I believe that the EXTENT in the MAP object is used as the default 
extents if non is explicitly or implicitly defined by other parameters. 
For example if you use:

http://server/cgi-bin/mapserv?map=/path/to/my.map&mode=map

Then you would get the EXTENTs and the SIZE for the image corrected for 
aspect ratio mis-matches.

Similarly,

shp2img -m /path/to/my.map -o junk.png

would like-wise generate the same image.

-Steve

John Mitchell wrote:
> Hi,
> 
> What are the advantages or disadvantages of having the map file header 
> extent the actual bounding box of the raster data that is displayed 
> instead of the world wide extent 
> (i.e. -180 -90 180 90 ). I have listed the top of a map file below as an 
> example with the world wide extent.
> 
> Thanks,
> 
> John
> 
> MAP
> 
>  # all temp files get prefixed with this string
>  NAME All_Raster_Layers_ignore
> 
>  # always returns a map
>  STATUS ON
> 
>  # image format options
>  OUTPUTFORMAT
>   NAME png
>   DRIVER "GD/PNG"
>   MIMETYPE "image/png"
>   IMAGEMODE RGB
>   EXTENSION "png"
>  END
> 
>  # projection of the INTERFACE that this mapfile supports
>  PROJECTION
>   "init=epsg:4326"
>  END
> 
>  # minx miny maxx maxy
>  EXTENT -180 -90 180 90 # World
> 
>  # units of map/app
>  UNITS DD
> 
> 
> 
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