How to Source Commercial Satellite Imagery
When Google Earth was launched in 2005, high resolution satellite imagery suddenly became easily accessible to anyone with an Internet connection. Much of this high-resolution imagery (50-60 cm) is provided by Digital Globe and can be used for a wide range of commercial applications such as urban planning, engineering, utilities and more. Satellite imagery is a great option for mapping large, remote or inaccessible areas where orthophoto is not available. So, how is the imagery captured, and how can a commercial user purchase the imagery?
Digital Globe has three satellites, or sensor vehicles, to choose imagery from, QuickBird, WorldView-1, and WorldView-2, and plans to launch WorldView-3 in 2014. These sensor vehicles are in a sun-synchronous orbit, imaging the Earth pole to pole every 90 minutes at a speed of 25,000km/hr, capturing panchromatic (grayscale) images and up to 8 colour bands. These bands can be displayed in different combinations on the red green and blue channels of your GIS software to show natural colour images, or create false colour images such as infrared, to highlight areas of vegetation and classify surface materials.
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The satellites capture images in long strips, swaths less than 18 km wide and more than 100 km long. The satellites don’t necessarily point the camera straight down (at nadir), they can ‘slew’ or move up to 30 degrees from side to side to capture neighbouring strips. In less than 2 hours from the time of capture, the imagery can be downloaded to stations on the ground for processing such as correcting for ground relief by applying a coarse DEM, orthorectification, prepared for stereo pairs, or merged into a larger mosaic.
First Base Solutions is an authorized reseller of Digital Globe imagery and can navigate the technical specifications to place orders on behalf of your company. Customers can choose from a catalogue of existing imagery from all over the world dating back 10 years, or, choose the specifications to capture custom imagery. We welcome your questions and invite you to contact us for a quote.