<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>I have been using the GDAL utilities. But ran into a snag. We create KML overlay files, basically KML file that geolocates a PNG on google maps. This PNG is a vector image as well as can have 1 or two colors other than the transparent background. We used gdal to convert this to a GEOTIFF using the gdal_contour and this work quite well, its ignores the colors for the most part, as all we want is a poly of the colored areas, don't care about what color. gedal_polygonize, sees all colors and seams much more rough. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>in both cases, we generate a KML shapefile, but it appears they create line entries vs polygons.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>We also use ogr2ogr to simplify the KML as well. Can anyone give me some better method to get a pologyon for only the colored areas , ignoring changes in color.?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'><b><u><span style='font-size:10.0pt;color:black'>Dennis Burgess,</span></u></b><b><i><span style='font-size:10.0pt;color:#002060'> </span></i></b><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>