mapxy and scale with img.x and img.y

[Stephen Lime]

img.x and img.y (or imgxy) imply the use of an input image, that is, the user
is clicking in an image. In order to turn that click into a coordinate you need
image size and the extent of the image that was clicked in.

mapxy with scale/buffer implies you're NOT using an input image. If you don't
supply the imgext parameter (which defaults to -1,-1,-1,-1) you'll end up with 
some interesting results.

Bottom line: mapxy with scale/buffer and mapext are useful for initializing an 
application or using the software as an image/query engine. Img.x/y or imgxy etc 
are necessary when doing interactive apps. Be careful mixing the approaches.

Steve

The 2 techniques are mutually exclusive, with img.x/y taking precedent.

Stephen Lime
Internet Applications Analyst

Minnesota DNR
500 Lafayette Road
St. Paul, MN 55155
651-297-2937

>>> Nicolau Werneck <nwerneck at yahoo.com.br> 01/09/01 10:59AM >>>
OK, let's see if I can beat the record of newbie
questions!


Why don't img.x/y  work when whe call a map using
mapxy/scale pair instead of mapext?

the map i'm calling with mapxy and scale is comming
perfectely, but when I use mapxy, scale and img.x/y,
the resulting map points somewhere near the guinea
gulf (arount the 0,0 point!)

I know you may not have the answer. Probably it's jut
another stupididy  of mine, but writting helps a lot!
:>

thanks,
--Nicolau

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