[R-sig-Geo] [O/T] pixel question

Barry Rowlingson b.rowlingson at lancaster.ac.uk
Sun May 27 08:56:35 CEST 2012


On Sun, May 27, 2012 at 4:42 AM, Hodgess, Erin <HodgessE at uhd.edu> wrote:
> Dear Geo People:
>
> I tried to look this up on the Internet, but couldn't really find my answer.
>
> If a satellite has 16 km resolution, how many pixels/megapixels is it using, please?
>

 A satellite image (as a geoTIFF or jpg or other raster file) will
have as many pixels as the width of the image in km divided by the
pixel resolution of the image.

 The number of megapixels in the sensor is something the satellite
company know, and might be unrelated to the number of pixels in
supplied imagery since often it will be montaged or processed.

 Note that your final imagery might not have a pixel resolution the
same as the satellite's quoted resolution due to processing.

 So its not as simple as with digital cameras for ordinary human photography!

Barry



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