Group items tagged

"Tixik Heatmaps - Lets you add a basic heat map to a simple Google Maps display."

"The OpenHeatMap site lets you create heat maps and choropleths from uploaded spreadsheet data (CSV format), or Google Docs Spreadsheet data (which makes it continuously updatable). It supports location coding by latitude/longitude coordinates, or by a large number of name/code attributes (e.g. address, FIPS code, zip code, state, province, country). And as a bonus, you can also have time as a variable, letting you create animated heatmaps or choropleths."

This FAQ describes the Diigo Educator "upgrade" which is free and available by applying following the link on this page.