Courtesy of Google Earth / AP A photo taken during the Fin del Mundo Marathon in Ushuaia, Argentina, is matched with a similar view seen through Google Earth software. Users can add their own pictures and comments to the maps.

Online photo albums I had prepared for family and friends weren't capturing the essence of my travels to the southern reaches of the world. Then a light bulb clicked as I was exploring Google Earth: Why not use that?

Google Earth is a mapping product much more powerful than the typical Web-based map service. Applying mathematical algorithms to satellite and aerial images, with help from topographical data collected from the space shuttle, the free software lets you explore the world from your computer.

You can share your expertise on specific locales by adding comments, embedding photos and distributing them to the world. I couldn't wait to contribute my own views of glaciers, forests and the Beagle Channel shot during an 18-day trip to Antarctica and South America, the third and fourth continents in my ongoing quest to run a marathon on all seven.

Software is overpowering

Figuring out how to use Google Earth proved challenging, though, and figuring out how to share my collection was even trickier. I was quickly overwhelmed because the software can do so much, and I couldn't see where or how to begin. The online user guide provides so much information that I got impatient with it. Relief came when I found step-by-step directions on an online bulletin board.

I began by finding Ushuaia, Argentina, and my hotel on the map, adding what Google calls a "placemark" — a three-dimensional bookmark that remembers the location, altitude and angle from which you are viewing.

I added several placemarks along the route of the 2007 Fin del Mundo Marathon, which proved difficult because nearly half the race was through a national park. I had to approximate the route using landmarks such as streams and mountains in the photos.

Had I taken along a GPS device and "geotagged" my photos with latitude and longitude coordinates, a technique still mostly limited to the tech-savvy and professional photographers, this wouldn't have been an issue.

About 12 miles into the race, I had stopped to take a photo of houses with snow-covered mountains in the background. Initially, I added a simple placemark as if the location were viewed from above.

But then I sought to match what was on the screen with what I had in my photo. That meant tilting and rotating the Google Earth view until I was looking north from nearly ground level. The match was quite impressive.

Next I tried to embed photos in the pop-up balloons attached to each placemark, but this requires a rudimentary knowledge of HTML, the Web programming language. I had to search other Web sites for the syntax I needed to embed images hosted on an outside photo-sharing site, and I had to find the proper tags to create line breaks for captions.

Once I had my collection close to my liking, I proceeded to share it — e-mailing my placemarks, photo links and other data in a "KML" file to some friends and colleagues.

Those with Google Earth already installed could open it fine. Others couldn't easily figure out that the file also opens in the Web-based Google Maps service.

Viewers have problems, too

I purposely gave few instructions to test how easily others discover features, then checked with them for feedback.

No one noticed the "touring" capability — my favorite part of viewing the completed project. It lets you automate a presentation; the map zooms in and out and moves from one placemark to the next as if you are watching a movie of the race recorded from a helicopter.

When I was ready for Round Two, I added photos from each of the seven marathons I did last year — from Antarctica to the Arctic.

This time, I shared my collection through a public bulletin board. It could take weeks or months for my items to automatically appear when users enable the "Google Earth Community" layer in the software, but people can manually find and download my file directly from the forum.

With time, I can see adding more data points, such as the more than 30 state capitals I've visited, all the homes I've ever lived in and all the restaurants I've enjoyed, perhaps with links to recipes or photos of my favorite dishes.

Waiting for next iteration

That said, it'll probably be awhile before I get around to continuing the task. I am fairly comfortable with the basics of Google Earth now, and I do enjoy creating the presentations. But sharing my Google Earth creation was far more cumbersome than sending a link to an online photo album with an easy-to-find "slideshow" button.

Although many of Google Earth's features are likely second nature to longtime users, they are relatively new to me and people I know.

Google says it is working to improve usability, and I look forward to future iterations.

On the Net:

Google Earth: http://earth.google.com

Step-by-step basics:

http://bbs.keyhole.com/ubb/showflat.php/Cat/0/Number/16256/an/0/page /0

Gallery of KML files: http://earth.google.com/gallery

Seven marathons: http://tinyurl.com/3s26mj