Message posted by Peter Merlin on November 10, 2016 at 6:51:58 PST:
Google Earth imagery is a combination of satellite and aerial imagery from a variety of different platforms, so the resolution is likely to be uneven from place to place depending on coverage. At one magnification, you might be looking at satellite imagery and then zoom in to aerial photos. As to resolution with regard to commercial satellite imagery, things are getting better. Until recently, U.S. commercial providers have operated under government license that prohibited selling imagery with better than 0.5-meter (20-inch) resolution to any customer not explicitly granted a waiver by the U.S. Government. This required commercial providers to either take only low-resolution imagery or to re-sample high-resolution images to degrade the picture quality before consigning them to the customer. In 2013, to better compete against foreign companies not under such restrictions, DigitalGlobe successfully petitioned the Commerce Department and NOAA to relax resolution limits. The WorldView-3 satellite, launched in 2014, is capable of resolving objects as small as 31 centimeters (12 inches) from an altitude of 383 miles above Earth’s surface. Six months after WorldView-3 became operational, the company was permitted to sell panchromatic (black 7 white) imagery with a resolution as fine as 25 centimeters (9 inches), as well as 1-meter resolution multispectral imagery and 3-meter infrared imagery. These same services will be offered by Worldview-4, scheduled for launch this Friday from Vandenberg Air Force Base. So far, DigitalGlobe seems to have a monopoly on the highest-resolution imagery. They decided to launch Worldview-4 (formerly GeoEye-2) to support the high demand for their products, which I have to admit look pretty impressive. The straight-down, overhead images obviously have the most detail, but the oblique views are also very impressive even from a distanced of around 1,400 miles. As an interesting sidebar, the company used Worldview-1 to take a series of images of the Atlas rocket carrying Worldview-3 into orbit from Vandenberg. The detail is stunning.
In Reply to: Satellite Resolution. posted by WheresJanet on November 09, 2016 at 20:55:17 PST:
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