[OSM-dev] Cutting up an image into tiles
Ludwig M Brinckmann
ludwigbrinckmann at gmail.com
Wed Feb 28 12:35:03 GMT 2007
The question is of course whether the image has been orthorectified or not.
I assume it is actually a mosaiced image assembled from multiple arial
photos that has been corrected for distortions due to terrain and the
photographic process. The process behind this is most likely to be much
better than anything you can do by hand -- better not cut it up, as you will
not improve anything.
If it is a tiff image it might be a geotiff -- ie a tiff images with tags
that give coordinates. The program gdalinfo (part of the GDAL suite or
FWTools -- a suite of geotools that solves all dependencies). If gdalinfo
spews out some coordinates, you are most likely to have a orthorectified
image. Which could then just be used with mapnik or mapserver
On 2/28/07, Nick Black <nickblack1 at gmail.com> wrote:
> I have a TIFF image map of the Isle of Man at approximately 1:25,000
> scale. The IoM Gov have given dervative rights to OSM to use it to
> produce data from. I need to cut the image up into smaller tiles,
> which I was then planning on rectifying using the metacarta rectifier,
> then using the JOSM WMS plugin the trace the roads.
> So can anyone point me in the direction of some guidelines about
> scripting ImageMagick / Rmagick , or something the cut the image up -
> which shouldnt be too hard to do? I dont have access to the TIFF
> right at the moment, but its big. Over 80mb I think.
> Nick Black
> dev mailing list
> dev at openstreetmap.org
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