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<body class='hmmessage'><div dir='ltr'>Hi all,<br><br>today I've finished the work on the shape merger.<br>The algo works quite simple:<br>1) if two similar shapes (same type, name, min+max resolution) share<br>one or more identical points, both are combined.<br>In the combined shape, the longest sequence of identical points is removed.<br>This reduces the number of points and the number of shapes.<br>On the other hand, it makes shapes larger, so that it is more likely that<br>many smaller landuse=forest shapes are combined and appear at<br>lower resolution levels.<br><br>2) After merging, all points on (almost) straight lines are removed.<br>This reduces again the img size and has a very nice side effect:<br>Connected buildings look much better.<br>Two screen shots show what I mean:<br>Area in OSM:<br><a href="http://www.openstreetmap.org/node/21030850#map=17/53.06636/8.79033" target="_blank">http://www.openstreetmap.org/node/21030850#map=17/53.06636/8.79033</a><br>Screenshots:<br><code>http://files.mkgmap.org.uk/download/170/r2961.png</code><br><code>http://files.mkgmap.org.uk/download/171/r2966_mergeshapes.png</code><br><br>I see no big change in the runtime , I guess the additional cpu time that is needed for the<br>merged is gained back because less data is written, the img size is 2-3% smaller<br>compared to trunk.<br><br>Any feedback is welcome.<br><br>Gerd<br><br><br> </div></body>
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