[Freegis-list] Lat/Long to Pixel Conversion for the Web
bernhard at intevation.de
Thu Feb 26 17:42:07 CET 2004
On Sat, Feb 14, 2004 at 04:44:46PM -0600, Mike Anderson wrote:
> I am new to GIS so bear with me. I have a ton of devices that I have the
> lat/long coordinates for. What I would like to do is find the corresponding
> bitmap pixel coordinates for these lat/longs in order to (1) plot my
> devices on a scaled
> .gif and (2) generate a web imagemap behind a scaled .gif.
> So, I've got the lat/longs, I've got a scaled image, I can find several
> points on the image where I know the lat/longs AND pixel values (if that
> makes any difference).
Usually you have to do
1) georeference your image,
meaning that the software will know where each pixel is
GRASS can do that, but it might be a bit overkill for the task.
Maybe you can do a poor man solution involving step 2.
Try so many projectiong, until it roughly fits for the
purposes of drawing.
2) project your lat/long coordinates in the map coordinates
Your map coordinates are the pixel in this case.
A lot of Free Software can do this.
If you did 1) then displaying the points should be easy.
Check out igmt.
Professional Service around Free Software (intevation.net)
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