07 September 2005

Pictures from high above 4: San Francisco Steinberger Slough

This is the 2nd picture that I took on 30 June 2005 as my plane was approaching the San Francisco Airport. Yesterday’s photo was the salt evaporators just north of Redwood City. This one shows an area 4.1 km north of yesterday’s picture.

Once again, I was able to identify the area in the photograph thanks to the satellite photo at Google Maps. Note the power transmission lines crossing the canal (Steinberger Slough), visible in both my photo and in the Google satellite photo, which was taken from directly above.

The area in my photo is within the yellow rectangle in the topo map from TopoZone. Compared to the Google satellite photo, the topo map is hopelessly out of date: the area marked “salt evaporators” on the topo map is now covered with houses.

Using the scale bar on the Google satellite photo, I estimated the distance between the areas in yesterday’s and today’s photos as approximately 4.1 km (2.57 miles). The time difference between the two pictures, as recorded by my digital camera, was exactly 50 seconds. Using this information, I calculated the speed of the plane within that interval as 295 km/h (185 miles/h).

There is a 3rd photo taken about 10 minutes earlier. It shows a coastal development without any distinct landmarks. If I ever identify it on a map, I will post it here too.

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