by Felix Andrew
Geotagging
"is the process of adding geographical identification metadata to various media such as websites, RSS feeds, or images and is a form of geospatial metadata. This data usually consists of latitude and longitude coordinates, though it can also include altitude, bearing, and place names."
Geocoding
"is the process of assigning geographic identifiers (e.g., codes or geographic coordinates expressed as latitude-longitude) to map features and other data records, such as street addresses. You can also geocode media, for example where a picture was taken, IP addresses, and anything that has a geographic component."
- Wikipedia
How to tag your images
There are several ways to geotag photographs.
Cameras
Newer cameras have global positioning system (GPS) units built into them. When a photo is taken, it is automatically stamped with the camera's location. This method produces the most accurate results.
Handheld GPS units
Many handheld GPS units will record a route which can be uploaded to your computer. Special software can interpret these routes and compute your location at any given time. The software can then use the date and time on the photos to update the photo's GPS information.
Hardware devices
There are a small number of dedicated GPS units made specifically for still cameras. The Sony GPSCS1KA and GiSTEQ PhotoTrackr are examples. These units do not need to be attached to the camera—they can be kept in a bag or somewhere more convenient. They record their location periodically. When you have finished shooting, the GPS information is attributed to the images using the provided software.
Software only
Several applications allow you to add GPS information to photographs without using a GPS device. These tools allow the user to search on a map for a location and then apply the GPS coordinates to the photographs.
Many asset managers, including Expression Media, allow users to geocode their assets by entering city, state, and country information.
Geotagging in Expression Media 2
Virtual Earth window
Expression Media 2 introduces a new palette window called "Virtual Earth." This is accessible from the Window menu. The Microsoft Virtual Earth service is used to display GPS and map information. This requires that you have a connection to the Internet.
This user interface (UI) is split into two parts: the main map and the map controls. The information in the map is provided by Virtual Earth—which is used by sites like Live Search Maps.
Map controls
A few of the Virtual Earth controls are useful for geotagging your photos.
The first is the Interactive Search check box, which turns on the search fields for the map.
For this tutorial, we will focus on using the Where control. Type in the location name of a photo shoot and click Find. The map will move to that location.
The other controls on the map which help with geotagging are 3D and Aerial. 3D changes the view allowing the map to be viewed in three dimensions. Aerial uses photos which will help you find locations more precisely.
The information panel
GPS data is stored in exchangeable image file format (EXIF) data, as shown here:
EXIF data is typically considered read-only. Fortunately, the Annotations section geocoding fields have been extended to include Latitude and Longitude. This allows you to correct or add GPS locations to your existing photos.
Tutorial 1
Getting used to the map features
For this tutorial you will need two photos without GPS data in them.
Drag the two files into Expression Media and open the Virtual Earth window. Clear the Auto Move check box, and select the Interactive Search check box. Put the map into Aerial mode by clicking on Aerial.
In the Where box, type "Redmond, WA" and click Find. You should see an image like this:
In the thumbnail view, drag the first image onto the title of the window. A push pin should now appear on the map.
In the search box, type "Dulwich, UK" and click Find, and then drop the second image onto the map. The map should move to a new location, and look something like this.
Select the first image. You'll notice two things. The push-pin vanishes, and the Annotations panel should display data for latitude and longitude.
As you click between the two images, the push pin will become visible and then disappear. To have the map always show the location of the selected image, simply select the Auto Move check box. Moving between the two locations becomes more dramatic when the 3D map display is selected.
Tutorial 2
How to fine tune your locations
Select the first image. The map should move to Redmond. Clear the Auto Move check box. Drag the second image to the map. Check to see if the coordinates of both images are now identical.
Zoom the map in as far as it will go, the map should look something like this:
Move the mouse off the push pin, and slide the map a bit down and to the left. Drag the second image to the map. It will look as if the pin has moved. Now when you select both images you should see two push pins.
Tutorial 3
Geocoding GPS to city and country
GPS information is very convenient to use with services like Virtual Earth. However, typing in the city and country information for each image can be quite tedious. Using the customization features of Expression Media, you can access the GPS data and convert it to city and country information. There are several services which will do this.
Learn how to install a custom GPS script.
Tutorial 4
HTML galleries
Another way to leverage the GPS information is to produce an HTML gallery which uses the Virtual Earth experience to show off your trips.
