This is a great how-to on building a GPS system for your DSLR camera. The pictures are tagged with the exact GPS coordinates for later reference. Nice work!
This version eliminates the need for the expensive MC-35 and even the special 10-pin connector. I’ve opted for a quick GPS receiver and encased everything in a small black box with a flash shoe mount. Because it is powered through the camera’s power source, a switch on the side of the box turns off the GPS. Version 3 should include a battery, rechargeable through a USB connection.
DIY camera GPS project for Nikon DSLRs – Link