Blue Earth
Glazer's Camera

Bouncing Off the Satellites with GPS


You might have seen the television commercial with the suburban family who drove their sport utility vehicle to Tibet (actually some idealized rugged outdoor location) for a picnic and the inept dad locks the keys in the car. Saving the day, is a generation X customer service representative who locates the car from a far off high tech data-center. Satellites locate the car, unlock the door, saving the family picnic!

The space age technology seamlessly working behind the scenes in this scenario is GPS or Global Positioning System. GPS is a satellite locating system developed by the military, which is now available to the general public. GPS units locate a specific point on the earth through the low frequency radio communication with a minimum of 4 satellites of the 24 GPS satellites orbiting the earth. Location is determined by comparing the time for the radio signal to travel from the satellite to the GPS unit. Several satellite measurements are compared to locate the specific coordinates of the GPS. As long as the GPS unit has a clear view of the sky (even through glass) the low frequency radio waves communicate between the GPS and the satellite. Indoor, within a city and near steep canyon walls affects the accuracy of the reading.

A few different possibilities have arisen with the use of handheld GPS units and photography. Accurate location documentation and coordinate database attributes are two great features of GPS. Location documentation has never been more accurate; accuracy within 60 to 225 feet is now available. By documenting the GPS coordinate of image location, the photographer now adds a layer of geographical documentary referenced by a database, thus opening up many categorizing and searching scenarios for image retrieval. Attributes or descriptions are used to catalogue images. By adding GPS data to an image, another criterion for image organization is introduced.

Spreadsheet or cataloging software such as Filemaker can be customized with a GPS column entry. This data is added to slide mounts or as an attribute within a digital file manager program. Canto Cumulus features data fields including file name, description, location, and a variety of customizable fields named latitude, longitude, time, date and altitude. Creative techniques such as re-photographing historical locations or documenting seasonal variations are aided with these precision measurements. The decisive photographic moment is redefined in time and space with the time synchronization available within the Global Positioning System atomic clock. The time stamp is based on local or Greenwich Mean Time (GMT).

For sailors, aviators or others who have used GPS data previously, latitude and longitude are easily recognized and compared to other known locations. When viewing or capturing an image, latitude and longitude information juxtaposes personal experience with the visual perception of the photographic image. For example a caption or title "cedar tree in forest" could also display GPS coordinates which read N47*42.167' W122*03.750'. Those who are familiar with geographical data would see the 47* N measurement and think of similar locations throughout the world at that latitude. This same coordinate can be saved as a waypoint for future visits. Waypoints or specific locations are saved then stored within the GPS for later use. Comparison between locations and navigation between locations is easily previewed.

The Garmin GPS III is well suited for the photographer with it's easy to use controls, maps and data displayed on a 2.2 by 1.5 inches or 100 x 160 pixels screen. The backlit grayscale screen displays latitude, longitude, altitude, speed, bearing, maps, as well as a list of recorded waypoints. This portable GPS fits into a jacket pocket, backpack or camera bag. Water resistance is another great feature for those rainy excursions.

GPS information is now supported as a direct input into many digital cameras with a serial port. Kodak offers the Kodak GPS connection kit for the DCS series of digital cameras using the Garmin III. The kit includes a bracket, connection cable and scripting software. Latitude, longitude, time and date are recorded within the image file. DIGITA scripting communicates between the GPS and the DCS camera. Currently this Kodak bundled solution is marketed to law enforcement, cartography and civil markets. High-end professional level digital cameras including the Kodak Professional DC series and the Nikon D1 series (including the new D1X and D1H) accept GPS data, writing the latitude and longitude to the image file in a similar manner as the current ISO, time and date annotations. GPS data is stored with the specific image and available when previewing.

When directly importing GPS data into the digital camera, a tripod provides a stable platform for connecting the appropriate devices. By using a larger camera bracket, the digital camera and the GPS sit side by side and are easily connected and operated. For the totally wired individual, a Palm Pilot captures the GPS data through a companion GPS attachment. By connecting a GPS attachment to the Palm Pilot additional database capabilities are available. Palm Pilot's easy to use interface and pen based input is a lot easier to annotate than the toggle-controlled annotation within the Garmin GPS III unit. To simplify the processes further, a pocket notepad and pencil work well on location with serious database entry to follow when returning to the studio.

As technology encroaches on many aspects of modern life including the creative process, many choices are made as to the most efficient manner of accomplishing the task at hand. Adding a GPS to your camera bag could involve an elaborate process of gizmo control in addition to creating the image or be simplified by scribbling latitude, longitude, time, date and altitude on a scrap of paper. Either way the GPS adds an entire new meaning to "location".

George H. Thomas
Story Author: George H. Thomas

George H. Thomas is a digital media consultant and photographer based in Redmond, Wash. A Digital Image Glossary

Website: thomas-media.com E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it