Steve: actually tim's implementation creates a new point layer , dynamically creates images for each pie chart, and associates each of the points with its corresponding image. The overhead is quite noticeable for more than a bunch of pies to be generated.
<br><br>Steve and Daniel: the url type symbol does seem promising feature-wise. but once again the overhead of network request and probably two intermediate files (one for owt, one for MS) seems quite important.<br><br>tb
<br><br><div><span class="gmail_quote">On 6/9/06, <b class="gmail_sendername">Steve Lime</b> <<a href="mailto:Steve.Lime@dnr.state.mn.us">Steve.Lime@dnr.state.mn.us</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Thomas: I hadn't looked at Tim's implementation but "thought" he was using<br>the pie chart demo I had put together. That is a native implementation. It<br>would be helped by a startangle parameter which would make data setup more
<br>intuitive. (this is what got RFC percolating in my head)<br><br>As for bar charts, I was thinking about that too. With attribute bindings for size<br>this is almost doable with styles now. That is, each style could represent a bar.
<br>with offsets applied to form the chart. The missing piece is that MapServer<br>locks the symbol aspect ratio for symbol scaling and/or allows only 1 size value.<br>One solution would be to allow size to set 2 values- width and height. With the second
<br>being optional. That would be a painful modification I think. A better option might<br>be to use with already present WIDTH parameter for markers, so the width would<br>define the marker width (if present) and size would represent height (which is what
<br>it really represents anyway). That would not be a difficult modification.<br><br>That would allow relatively simple charting, but for use as a marker that's really all<br>you could do.<br><br>One last idea would be to allow the use of a URL to define a marker. That would allow
<br>remote images to be used, but would also allow the use of external programs to do things<br>like charting (think OWTCHART) or custom markers. Allow that URL to be a template and<br>take item substitutions:<br><br> SYMBOL '
<a href="http://someserver.com/cgi-bin/charting?data=[X1],[X2],[x3],[x4]">http://someserver.com/cgi-bin/charting?data=[X1],[X2],[x3],[x4]</a>'<br><br>and you really have something interesting... With libcurl this might no be too bad.
<br><br>Steve<br><br>>>> thomas bonfort <<a href="mailto:thomas.bonfort@GMAIL.COM">thomas.bonfort@GMAIL.COM</a>> 06/09/06 7:37 AM >>><br>hi all,<br>I'd be interrested in having/adding pie charts or bar graphs to mapserver,
<br>in order to output thematic maps...<br>I've experimented with Tim Schaub's hack for pie charts which is very nice<br>but a bit too cumbersome for large datasets, and was wondering if this could<br>be natively done by mapserver...
<br>Could this fit in the symbology methods of MS, by defining a new type of<br>"dynamic symbol" which would resemble a pixmap symbol except that the pixmap<br>is generated from the input data?<br>I'd be willing to give a shot at this if you folks think this is worthwile.
<br>cheers,<br>tb<br></blockquote></div><br>