I am trying to make a map in QGIS 2.0.1 ( running on my Mac OS X Maveriks) with the proportionally sized (graduated) pie-charts. I have started with the csv conversion to kml just to place my sample sites on the map, and I am wondering if I can just modify this csv adding some extra columns indicating i) sample size and ii) percentage of each sector for the pie chart. Or there is much less complicated way?
Ok, after a few hours I found a solution:
No need to convert a csv file to kml for downloading to the QGIS, use the "Add Delimiter Text Layer" tool directly on the csv instead;
There is an annoying bug in Mac OS X - QGIS 2.0.1, which is not widely known (bug described here): when saving a csv in the TextWrangler in the saving options do not use "Line breaks: Classic Mac (CR)", but rather "Line breaks: UNIX (LF)" or "Line breaks: Windows (CRLF)", the Encoding was "Unicode (UT-8)" in my case;
When you import your csv to the QGIS described in 1), created in the manner described in 2), go to "Properties" > "Diagrams" > click "Display Diagrams" > choose "Piecharts" in the "Diagram type" > in the "Appearence" menu go to "Attributes" add the csv's columns you would like to build your pie chart with > in the "Size" unflag the "Fixed size" and voila!
Hope it will save someone's time struggling with mapping in QGIS.