Geocoding is also known as geotagging which is the process of adding latitude/longitude coordinates to a photo file.
Cells phones typically do this unless you set them not to. Many cameras are also enabled with GPS receivers that will geotag files. Barring that convenience you can geotag photos in Photoshop, Lightroom or online on sites like www.geoimgr.com.
Geotagging photos documents your photo-taking trail, which can be a benefit or possibly not. Geotagging is great for any photo where you want to remember the location. Anyone with your file and the ability to read it will also know the location.
However there also may be times when you not want a viewer to know the location of the photos. A friend recently sent me photos her chanterelle hunting grounds. Chanterelles are delectable wild mushrooms prized by chefs and mushroom lovers. She was surprised when I sent back a map of the location. Now, I can go clean it out before she gets there! (more likely I’ll just take some photos).
