[Mapserver-users] how to creat reference map?

[Thorsten Fischer]

On Wed, 2003-05-21 at 17:36, Dylan Keon wrote:
> What I do is create a minimal mapfile containing just the layers I want 
> visible in the reference map.  I use the same EXTENT as my regular 
> mapfile, but make the SIZE small (like 150x150).
> 
> Run shp2img against that mapfile, and you'll end up with a great 
> reference map image.  For example:  shp2img -m foo.map -o refmap.png

This will most likely be error-prone.

Consider you have such an EXTENT entry in your mapfile:

EXTENT 5.0 5.0 10.0 15.0

Now you set your SIZE as this:

SIZE 150 150

As you can see, the ratio of the extents is 1:2, while the ratio of your
image size is 1:1. The image will be padded, and most of all, the EXTENT
in your mapfile will not be the extent of the resulting image. That's
why I suggested to read the [imgext]/[mapext] in an cgi application for
the actual value of the resulting map image.


hth,

thorsten