Streaming Real Estate
February 22, 2007 by Patrick McClellan| Hazard du jour Reclamation in Reverse After Hurricanes Katrina and Rita plowed through the Gulf States in 2005, the USGS compared Landsat images snapped before and after the storms. They found that over 200 square miles of Louisiana's coastal real estate had been transformed into water by the disasters. Some of it will remain open water, reclaimed by the sea. Elsewhere it will likely turn into lakes. How much and how soon, only time will tell. Granted, the now-submerged coastal property was populated mainly by alligators and turtles. But the loss of these marshlands and barrier islands further reduces the natural protection of Louisiana's population centers from future storms. According to the USGS, Louisiana had already lost 1,900 square miles of coastal lands, primarily marshes, from 1932 to 2000. The 217 square miles of potential land loss from the 2005 hurricanes represent 42 percent of what scientists had predicted, before Hurricanes Katrina and Rita, would take place over a 50-year period from 2000 to 2050, even though they had factored storms into their model. (Details) This is one of many examples of how Landsat imagery aids our understanding of natural hazards and how to live with them safely. |
If you're like me, you aim for a window seat aft of the wing. Then, you wile away the airborne hours watching the real estate stream beneath you on your leg-cramping way to that business meeting.
Now, you can watch it in bed, with your laptop on your chest!
As I type, Oregon and California pass by, in full color -- and near real-time. Crossing a vast expanse of brown desert and puffy clouds, the verdant Sierra Nevada and Central Valley come into view. There's no guessing which city I'm over. They're labeled for me. Clear skies reveal Sacramento. The Bay Area, now in sight, is socked in beneath a layer of white, as much-needed rain pours down at an inch per hour outside my bedroom window here in Silicon Valley.
My "air carrier" zips along 425 miles above the ground at 48,000 mph. My "window" is a high-resolution digital camera aboard a satellite called "Landsat 5", and the US Geological Survey (USGS) website that displays its images. Each pixel on the scrolling terrain covers about two and a half football fields -- not rooftops by any stretch, but enough detail to get a sense of place in my corner of the city at this moment in time.
Landsat is one of the enduring successes of our federal science program. It's actually a series of earth-observing satellites, the first one launched back in 1972, when a California home could be had for less than the price of today's SUV. Landsat 5 and 7 are the two platforms currently in service. They orbit roughly from pole to pole.
Landsat 5's speed and trajectory are synchronized with the speed of the earth's rotation, so that it's always morning in the area beneath the satellite, about half past nine. (A low sun-angle is important for interpreting the images.) It passes over the same spot every 16 days.
Everyone's seen those horrifying "before" and "after" satellite images of the Indonesian coastline after the 2004 tsunami. That was Landsat 7's handiwork. And Katrina's wrath was captured in Landsat imagery the following year. (See "Hazard du jour" sidebar.)
The continuously-scrolling online images are extremely cool. They're "live" when the two orbiting satellites pass over North America. Between passes, the website replays scans from earlier orbits.
So, the next time the floodplains fill, the hills burn, or other natural hazards affect your region, you'll be able to monitor the developing scene from this "window seat."
Check it out: EarthNow! Landsat Image Viewer
Recommendation: A killer app for real estate professionals who "get" the Big Picture.
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