Aperture 3's Places is the slickest interface yet for geotagging photos, which means assigning location data to them. Importing a track from a GPS unit shows it overlaid in purple onto a Google map. Dragging a photo to a location on that track, if you know it, lets you assign those coordinates to the photo. Aperture then offers to assign coordinates to all the other photos in the group based on when they were taken and where on the track you were at that time. When you don't know the exact location of a photo, or if you managed to set your camera's clock correctly, you can drag a photo along the track until the photo time matches the track position time.