What does it show?
Hotmap shows where people have looked at when using Virtual Earth, the engine that powers Live Search Maps: the darker a point, the more times it has been downloaded. Each square represents one unit of imagery, called a "tile". When the program starts, it shows tiles at zoom level 11, which has tiles at a resolution of 74 meters-per-pixel. At the closest in, Virtual Earth has tiles at zoom level 19, 0.3 meters-per-pixel. You can look at higher- or lower-resolution points with the "select data level" indicator at the top.
A sample of imagery and a relative sense of what was in a given spot is available at each scale by right-clicking on the map. The "locator map" shows imagery at the specific point clicked.
This data is based on a sample of tile logs on servers from January through July of 2006; it is not live. It combines server hits from road, aerial, and hybrid imagery in one view.
What are the controls?
Hotmap shares many controls with the Virtual Earth system, but adds a control for the data level in the top left, and allows the user to right-click to examine a specific point.
How does it work?
Hotmap is a mash-up of data over the original Virtual Earth tiles. Hotmap generates new image tiles based on data stored in a database, and superposes them over Virtual Earth, using the AddTileLayer method.
Who made this?
Hotmap was created by Danyel Fisher, in the VIBE Group at Microsoft Research, using data provided by the Virtual Earth team. Thanks to Virtual Earth, Paul Johns and Aaron Hoff for help with the public deployment.