[mapserver-users] Re: quick question from mapserver beginner!

[Asuka Milano]

i hope this is the right way to reply, i just clicked on reply and sent 
it again to mapserver-users at lists.osgeo.org :) thanks for the comment, 
but i guess i didnt explain my situation well on my first post

BASELAYER: google hybrid
OVERLAY: my own mapserver map with a single LAYER - an image of a field

as you can see in the picture (here it is again: 
http://img688.imageshack.us/img688/5926/99138762.jpg), im really ok with 
rectangular shape of the overlay, the problem is that i want it to be 
smaller. i already made the layer small but the map itself with a black 
background remains big. in my case to start with, i can do fine with a 
map with just the size of its only layer. did i explain that well? :P

to make it clearer, imagine this sample scenario:
- google doesnt have a close up image of my house
- i have my own aerial high resolution image of my house so i want to 
overlay it above the image google provides
- problem: i already put my own image of my house above google's but the 
background of the map (which i assume is IMAGECOLOR 0 0 0) covers 
everything else
- i dont want to provide a raster of the entire world (im saying this 
because the black part covers almost the whole world), only of my house
- i believe it is possible to create a map with just a specific extent 
right? since there are SIZE and EXTENT values on the map file. but i 
dont know why it's not working for me


sorry if i misunderstood some stuff.. thanks again!

On 5/12/2010 8:28 PM, mattmendick wrote:
> You first have to make sure you are outputting the image as a png or some
> other image format that supports transparency. Like this, at the base of the
> mapfile:
>
>          OUTPUTFORMAT
>                          NAME mypng
>                          DRIVER "GD/PNG"
>                          IMAGEMODE RGB
>                          FORMATOPTION "INTERLACE=false"
>                          MIMETYPE "image/png"
>                          EXTENSION "png"
>          END
>          IMAGETYPE mypng
>
> Then, if your source image is not perfectly square, and has black in areas
> that you want to be transparent, you can use the "OFFSITE [R] [G] [B]"
> attribute. This tells mapserver that any color in the raster that matches
> the color in your OFFSITE parameter should be rendered transparent.
>
> ex:
>
> LAYER
>         NAME "blah"
>         DATA '/path/to/raster.tiff'
>         OFFSITE 0 0 0
> END
>
> This has worked for me in the past, I hope it works for you.
>
> -Matt Mendick
>