As I have promised in my article about Geotagging, today I’m writing about Geocoding. I won’t get too deep into Geocoding because you can find all the information you would want on Wikipedia. I want to write more about the relationship between Geocoding and Geotagging.
Definitions first…as usual
From Wikipedia we learn that: “Geocoding is the process of finding associated geographic coordinates (often expressed as latitude and longitude) from other geographic data, such as street addresses, or zip codes (postal codes). With geographic coordinates the features can be mapped and entered into Geographic Information Systems, or the coordinates can be embedded into media such as digital photographs via geotagging.”
There is also Reverse Geocoding which means obtaining geographic information from geographic coordinates. Just to make it simple, Geocoding means converting one set of geographic information, namely precise coordinates to another set of geographic information, namely location (country, city, state, etc) and reverse. I call Geocoding a transformation from location expressed in coordinates to location expressed in words … and the other way around.
What does Geocoding has to do with Photography?
Well, as you can imagine Geocoding algorithms are the heart beat of every application that deals with maps and directions. But what does Geocoding has to do with Photography ? Well, Geocoding algorithms can be used also in photography to compute one set of geographic information from another existing set of geographic information. If you have the Lat/Long you can compute the country/city/state location…and the other way around.
How do you do Geocoding ? Well you don’t…you needs some software program that will perform the conversion for you. However, you have to be able to get one set of information, whether manually or through some device that can obtain that automatically.
Geotagging and Geocoding are friends forever
In my previous article about Geotagging, I have explained that GPS coordinate information (Lat/Long) about an image can be saved in the EXIF portion of the image file. On the other hand, the human readable geographic information (Country, City, State/Subregion) metadata can be saved in the IPTC portion of the image metadata.
Geocoding algorithms can be used in software to transform one set of geographic information to the other. So, if you can provide the GPS Lat/Long in the EXIF metadata of the image file, the right software can just figure out the human readable geographic location metadata in the IPTC…and the other way around.
If you want to play with Geotagging your photos you can use a great little program that will take care of all the metadata for your pictures. I love this program and I will probably write a review of it soon.
I started using Picasa for geotagging my pictures. Ever since they have released version 3.5 (Read what’s cool in Picasa 3.5), Picasa makes it very easy to add geotags to your pictures. It’s just beautiful how they have incorporated Google Maps into Picasa.
Another way would be to download Geosetter and give it a shot. Just select some pictures on the left and then place a pin on the map where those pictures were taken. Then Click the top left button on the map toolbar. This will transfer the GPS coordinates into the EXIF portion of those images. Then on the Images toolbar click the pencil/paper icon and now you can obtain the country/city/state location that can be written to the IPTC. This program will also place the country and city into the IPTC keywords field as a bonus. Well…have fun and let me know what you think.