I am a Google Earth junkie
It has been a while since my last blog—I hope I am not breaking some sort of blog etiquette. I’d like to use the usual excuses (busy classes, sick kids, the government), but the truth is I am addicted to Google Earth. I like to mock people who waste hours in front of a television or who create elaborate virtual lives on the internet. Now, I am reduced to their rank. I sneak away to glimpse GE. I make steamy cups of tea and pick a spot to search (latest was the Egyptian coast on the Red Sea for 45 minutes where I found an unmarked shipwreck).
I even dream of GE. One of my daughters walked by with a way-too-full diaper but I found a high-resolution area of ooid shoals near the Tongue of the Ocean! Must…turn…off.
Now that I have admitted my shortcomings (one of the steps to recovery), let me tell why I have a new virtual love. GE allows you view high resolution photos of the entire planet (and much of space now) that come to life in 3-D. As a geologist, this allows me to quickly scan different environments for patterns, look for faults and folds on the Earth’s surface, and share the information with others. Also, as there are ways to quickly upload stories and photos, you can become a member of a global community whose posts range from vacation photos to humbling stories of war. The tools allow for a variety of explorations and many more are on their way from the Google team and independent developers who post their work online. And it is all free!
What I would like to do in this blog is give a brief background to Google Earth. Later, I will discuss the main tools useful to a field researcher, and give directions on how to share information. This will be kept short with the idea that more detailed blogs will be posted in the future.
How Google Earth works
Google Earth is a program that overlays satellite (and sometimes aerial) photos onto an elevation profile for the planet. The elevation information, known as a digital elevation model (DEM), is provided by NASA’s Shuttle Radar Topography Mission. This can be as accurate as 10 meters in some locations, most areas are about 30 meters. In some mountain areas, finer-scale DEM coverage leads to more accurate representation. The global datum used is WGS84. The base resolution is 15 meters per pixel, but many populated areas and other areas of interest are at 1 meter per pixel. In a few places, like Las Vegas and Berlin, exceptionally high resolution of 0.15 meters per pixel is available. Wow! Some areas are lousy at 500 meters per pixel and other areas suffer from cloud cover or low light on water. Still, the resolution is amazing.
Naturally, this leads to some concern from governments and privacy advocates and some areas, like Dick Cheney’s residence, are intentionally blurred. The entire nation of Israel is limited to 2 meters / pixel or less. (So far, the rocks haven’t complained yet).
Next blog…tools of Google Earth.
Tags: Google Earth, Mapping, software
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October 14, 2007 at 6:06 pm
I am also a google earth junkie. When they added the flight simulator easter egg, I just cannot get enough of it. Flying around with the fighter plane is amazingly fun.