Canon
GP-E2
GPS receiver
This hotshoe mounted GPS receiver is compatible with the EOS 1D-X, 7D, and 5D Mark III DSLRs. It automatically appends latitude, longitude, altitude, and viewing direction to the EXIF data of your images. It also features a logging mode, which lets you review your route once the data is downloaded to your computer, and can synchronize your camera's clock with the GPS clock signal for maximum accuracy.