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I have a KMZ file that contains several image overlays (RF coverage plots).

I would like to convert the image overlays to polygons to decrease loading time in Google Maps.

Currently I'm tracing a rough outline of the image but that is labor intensive and not very accurate.

Is there a way to automatically convert a image to a polygon?

I have Google Earth and Manifold GIS. ArcScan looks promising but it is outside of my budget.

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up vote 6 down vote accepted

You can use GDAL tool inside Quantum GIS. Its free and it works fine. Install Quantum GIS and Gdaltools and you'll have a set of tool for raster/image processing. The one you want would be vectorize (gdal_polygonize). Cheers

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It couldn't taking kmz file as input??? – satya chandra Nov 5 '13 at 10:47

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