Resize/colorize data points on a map
This is a special version of the GPS Visualizer map input form that's designed for plotting quantifiable data on a map. You can colorize and/or resize the points according to a generic frequency field named "N", or you can use a more typical field, such as altitude, population, or category.
If you have TRACK data, or if you DON'T need to automatically colorize/resize your data points by a particular parameter, you'll probably be better served by the normal Leaflet/Google Maps form, the Google Earth KML form, or the JPEG/PNG/SVG form. If you want your map to load markers dynamically (e.g., from a Google Docs spreadsheet), you definitely need to use the standard HTML map form.
The coordinates of your data can be given as latitude/longitude, as geographic places (city-state pairs, states, or countries), U.S. ZIP codes, or Canadian postal codes. For instance, if you wanted to see how many people in each ZIP code responsed to a survey you sent out, this would be a minimal valid .csv file: zip,N
Please contact Adam Schneider, using the address on the bottom of this page, if you have any questions about how this form works!