It is common now to assign metadata to web pages. This data provides extra information on the content, and is often automatically generated by the software used to create the page. For example, most blogging applications add the time and date the post was published, and the name of the author. It is usually also possible to add keywords to articles, videos, podcasts and photos to give an indication of the kind of information contained on the page. Adding these tags, as they are also known, helps search engines to index the content, and makes it easier for people to find.
Increasingly, geospatial data, usually latitude and longitude coordinates, are added to web pages, which can help anyone looking for information from a specific location. This can be especially useful for photographs since geotagging can give the exact location of where the photograph was taken.
A series of geotagged photos could be used to show the state of a rural road system, or record changes to an area over several years. The photos could show, for example, if deforestation has taken place in one area, or illustrate the changes in the crops of a particular field over a single growing season. Geotagging is also a useful way to organize photos.
There are three main ways of geotagging photos:
1. GPS-enabled camera
There are several digital cameras now available that will automatically tag your photo with the GPS (global positioning system) coordinates of where the picture was taken. The cameras usually come with software that will plot the photos onto a map, showing the location of where the photo was taken. Most of these cameras are still expensive, however (over US$ 1000), but cheaper models are gradually becoming more available, such as the Nikon Coolpix P6000 and the Samsung ST1000 GPS-enabled camera (both around US$ 500). The iPhone 3GS will also geotag photos taken with the device.
2. Camera plus GPS receiver
If you have a digital camera and a separate GPS receiver you can log your location when you take a photo. If the clock on your camera is synchronized with the clock on the GPS receiver, you can easily match the data later. A simple way to do this is to use software such as Geotag. The program is written in Java and will run on most operating systems. It can be downloaded for free, or you can run it straight from the website, http://geotag.sourceforge.net. With the Geotag window open, add the photos and the log file from the GPS receiver. The program will then match the two and show the photos at their locations on a map.
Even if you do not have a GPS receiver, there are a few websites which allow you to add location information to photos. The advantage of this method is that you can give the exact location of the subject of the photograph. For example, a photo of a distant mountain can be placed at the location of the mountain, whereas a GPS-enabled camera will only give the coordinates of where the photo was taken. It is also possible to scan old photos and set their location with these services.
Click ‘upload your photos’, then log in with a Google username or create an account. In the next window, click ‘browse’ and add the photo from your computer hard drive or memory card. When the photo has been uploaded, click ‘map this photo’, then type in the location of the nearest town or village in the search box provided. You will then see that location plotted on a map with a marker. Click the marker with your mouse and move it to the location of the photo. Click ‘save position’. You can then give the photo a title, add other tags and a comment or description. When you click ‘save’ you will then see your photo on the map. By clicking the link ‘in Google Earth’ you can download a file that will let you view the photo on the Google Earth program.
Log in to Flickr, or sign up for a new account. Click on ‘upload photos’ and follow the instructions to upload your photos to the site (there are three ways to do this). After uploading the photos, click ‘organize and create’ then ‘your map’. The next window will show the uploaded photos in a row below a map. Type the name of a nearby town or village in the box ‘find a location’, then click and drag the photo to the exact location on the map. Click ‘edit photo’ to add tags and a more detailed description.
Another simple way to geotag photos in Flickr is to use the loc.alize.us application. Go to the home page www.loc.alize.us and click ‘create’. Click and drag ‘localize bookmarklet’ to the bookmark toolbar of your browser. Go to a photo page on Flickr and click the bookmarklet. A box will open where you can enter the nearest place name, address or GPS data, if available. A map then shows the location. Zoom in, if necessary, and move the cross to the exact location of the photo. Click ‘save location’ and then enter a title for the photo.
It is also possible to drag your photos to a location on a map with the Geotag program.
Photos uploaded to Flickr, Panoramio and other photo sharing sites can be viewed by anyone with internet access unless you change your default privacy settings. Flickr also provides the possibility to change the privacy settings for individual photographs: click ‘organize’, ‘your map’ and then double-click the photo to edit the privacy settings.