<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Com diu a baix, comparar superfícies amb una projecció de tipus Mercator és agosarat. Però com a divertimento està molt bé!<br><br><h3 style="margin-left: 40px;">Shape Distortion</h3>
<p style="margin-left: 40px;">If you draw the outline at a given latitude in the Reference map, and
then view the outline at a different latitude in the Comparison map,
the relative orientation of the marker positions will be distorted. This
distortion occurs for two different reasons.</p>
<p style="margin-left: 40px;">First, Google Maps uses a
<span class="extlink">Mercator projection</span>
for its maps. By design, this projection distorts distances at different latitudes. Distances are magnified at higher latitudes.</p>
<p style="margin-left: 40px;">Second, my calculation of comparison marker positions attempts to
preserve true distances between markers. These calculations account for
the fact that units of longitude have different lengths depending on
latitude. The calculations somewhat reverse Mercator distortions of
horizontal distances, but not vertical distances.</p><br><br>--- On <b>Wed, 2/23/11, Raf Roset <i><rafroset@gmail.com></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>From: Raf Roset <rafroset@gmail.com><br>Subject: [Geoinquiets Barcelona] comparar zones<br>To: barcelona@lists.osgeo.org<br>Date: Wednesday, February 23, 2011, 11:05 AM<br><br><div id="yiv512154232">Per comparar superfiícies a Google Maps <a rel="nofollow" target="_blank" href="http://mapfrappe.com/index.html?show=2385" style="display: inline;" id="yiv512154232permURL" class="yiv512154232validPermaLink">http://mapfrappe.com/index.html?show=2385</a> (no som res!)<br><br>Raf<br>
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