Playing around with Google Earth

Notes:

You can easily move placemarks by accessing their 'properties' then clicking and dragging. You can NOT easily move polygons in the same manner. Maybe that should be a design consideration.

Found a great application that makes all sorts of graphs in GE, called GE-Graph.
He (?) makes the circles as groups of 21 points (first and last the same), so not a true circle.

If you want multiple placemarks within the same file, they must be enclosed by a <Document></Document> tag. Otherwise, GE complains about having too many 'roots'.

Within the <Document> tag you can define a lot of styles using <style id="foo"></style> then reference those styles in the document using <styleUrl>#foo</styleUrl>.

Within a <Placemark> you can only have one point, polygon, etc. Otherwise, it only shows the last one. Unfortunately you can't click on polygon's to view their properties or description. It seems like the easiest way is to create two placemarks for each location. One that is a point, that the user can click on easily, the other the pie chart. Put these data in different folders (<Folder></Folder>) so you can easily turn off the labels.