I haven’t covered geotagging — adding location data to digital photos (and then doing neat things with that data) — as much as I’d like to, and I’ve got a lot of links on the subject gathering dust in my files. But in the meantime here are a couple of recent items worth mentioning.

The first step in any geotagging enterprise is to add latitude and longitude data to the photo. Once that’s done, you’ve got several options. Many people (myself included) use Flickr for sharing online photos; it’s easy to tag the photos, so it’s easy for geotagging services to use Flickr as a starting point. (They also tend to use Google Maps, whereas Flickr is now owned by Yahoo!; you may safely assume that any “official” geotagging service from either Google or Yahoo! will break that link.)

But to tag your photos with lat/long coordinates, you have to know them — so you have to find them in a mapping service and plunk them in manually. This page automates it somewhat: you find your location on the included (mashed-up) Google Map, and copy the tags and description (it creates a link to a Google Map location) over to your Flickr photo. Via Flickr’s Cartography group.

Meanwhile, Richard wrote me last night to tell me about his page on geocoding photos, which points to some of the more automatic ways of geocoding photos rather than manually adding them: built-in camera interfaces, cellphones, GPS receivers. The upshot is that we probably won’t have to geotag our photos forever; we’ll expect our cameras to do it for us.