Rivers and KML
If you've been to the Telling River Stories website (http://www.riverstories.umn.edu), you've probably seen the colorful polygons over the states that you see on the zoomed-out version of the map. These polygons describe the states that border the Mississippi River, split into three groups.
Technically, this is accomplished by displaying a KML file, generated with Google Earth, on the map. At the moment we're considering the value of adding information to the KML file - first and foremost, a line tracing the river itself seems called for. Perhaps also a polygon that describes the boundaries of the Mississippi River watershed? At what point do we consider adding other rivers/tributaries?
We've got an interesting "feature" with our KML file at the moment. Different browsers seem to display the three state-polygons and the one river-line in a different order, so each time you refresh the page, the river may flow under -or- over a polygon. While conceptually interesting, and adding a lot of fun to page refreshing, this isn't a desirable feature.
I haven't yet found a way to force the display order of KML objects on all browsers, so perhaps they'll need to go into separate files.