<div dir="ltr"><div style><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">Apologies for a second message, the previous one did not make it to the list (the attachement exceeded 50KB).</span></div>
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px"><div style><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">Hopefully, this time will make it.</span></div><div><span style="font-family:arial,sans-serif;font-size:12.727272033691406px"><br>
</span></div><div><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">----</span></div>Thanks very much for these hints.</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">What I would <really> want to achieve is a sort of a spline contour.</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<br style="font-family:arial,sans-serif;font-size:12.727272033691406px"><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">In the mean time, I've played with QGIS (and </span><a href="http://mapshaper.org/" target="_blank" style="font-family:arial,sans-serif;font-size:12.727272033691406px">mapshaper.org</a><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">), both of</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">them make a good job to simplify the Shape file, but the number of</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px"><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">vertices is still too high for a webpage (my intention is to simply</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">make an interactive map with coloured polygons function of some social</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">indicators). The geographical information is of a little interest</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px"><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">here, but very important are:</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">- visual appeal</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px"><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">- size of the map, given that it's included in a webpage (a small SVG</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">definition is perfect)</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px"><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">From QGIS, I've exported a SVG file and at a first impression it has</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">way too many details. A "smooth" contour would be ideal, something</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">like in the attached print screen (not sure if it will go through the</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">r-sig-geo archive, though).</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px"><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">Will play with rgeos::gSimplify and GRASS, if this would be achievable.</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<br style="font-family:arial,sans-serif;font-size:12.727272033691406px"><span style="font-family:arial,sans-serif;font-size:12.727272033691406px">Best wishes, thanks again,</span><br style="font-family:arial,sans-serif;font-size:12.727272033691406px">
<span style="font-family:arial,sans-serif;font-size:12.727272033691406px">Adrian</span><br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Oct 30, 2013 at 11:42 PM, Roger Bivand <span dir="ltr"><<a href="mailto:Roger.Bivand@nhh.no" target="_blank">Roger.Bivand@nhh.no</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Wed, 30 Oct 2013, Alex Mandel wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On 10/30/2013 01:59 PM, Adrian Dușa wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Dear All,<br>
<br>
A question from a very beginner with maps and geographic data.<br>
I have a map with many (too many) vertices which I would like to use<br>
interactively over a web page. What I need is to simplify that map,<br>
make it <similar> to the original one but discarding 90% of the<br>
current information.<br>
<br>
I read that is possible using QGIS (which I have installed), but I<br>
wonder if it would be possible in R. I would gladly use an R function<br>
instead of learning how to use QGIS.<br>
<br>
Thanks in advance,<br>
Adrian<br>
<br>
</blockquote>
<br>
Not an R method but way easy, <a href="http://www.mapshaper.org/" target="_blank">http://www.mapshaper.org/</a><br>
<br>
</blockquote>
<br></div>
but no documentation anywhere, not on github either, but you get what you might expect, maybe?<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
A quick search shows several R packages that also have the<br>
Douglas-Peucker algorithm. Look at 'shapefiles' or 'cshapes' packages<br>
</blockquote>
<br></div>
The obvious choice is rgeos::gSimplify, unless you need to preserve topology accurately (which mapshaper doesn't do either) - GEOS will have shared nodes, but not all on an arc will be shared. If you need simplified arcs, use GRASS from R.<br>
<br>
Hope this helps,<br>
<br>
Roger<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Enjoy,<br>
Alex<br>
<br>
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</font></span></blockquote><span class="HOEnZb"><font color="#888888">
<br>
-- <br>
Roger Bivand<br>
Department of Economics, NHH Norwegian School of Economics,<br>
Helleveien 30, N-5045 Bergen, Norway.<br>
voice: <a href="tel:%2B47%2055%2095%2093%2055" value="+4755959355" target="_blank">+47 55 95 93 55</a>; fax <a href="tel:%2B47%2055%2095%2095%2043" value="+4755959543" target="_blank">+47 55 95 95 43</a><br>
e-mail: <a href="mailto:Roger.Bivand@nhh.no" target="_blank">Roger.Bivand@nhh.no</a><br>
</font></span></blockquote></div><br><br clear="all"><div><br></div>-- <br><div dir="ltr">Adrian Dusa<br>University of Bucharest<br>Romanian Social Data Archive<br>1, Schitu Magureanu Bd.<br>050025 Bucharest sector 5<br>
Romania<br>Tel.:+40 21 3126618 \<br> +40 21 3120210 / int.101<br>Fax: +40 21 3158391</div>
</div>