A GPS in a camcorder can store the location of where the photos were taken (also called GeoTagging). This allows you to see where you have taken photos in the world or organize your photos by locations.
Optical zoom means that the lense physically extends to magnify your subject. A motor controls the lens movement. When you press the switch to "W" or "T," the subject is either magnified or reduced in size. The "W" stands for "wide-angle" (reduce). The "T" stands for "telephoto" (magnify). Optical zoom always give better quality than digital zoom.