[topherhaddad]

I totally agree the 9x is somewhat marketing speak, but I do think that the way GSD has historically been characterized by the 1-dimensional measurement does not do spatial resolution improvements enough justice. Electro-optical imaging systems are analogous to any digital sampling system. If you were sampling a sine wave at 90 Hz instead of 10 Hz, that's clearly a 9x improvement as you end up with 9x more samples. The same is true for imaging, you're digitally sampling an object with discrete pixels (of course there's more to overall image quality than just spatial resolution). Another side note is that the government NIIRS imagery rating system captures this squared effect through the log2(GSD) term in the equation. Photographers also think more about it in 2D, as they characterize resolution in total Megapixels in the image. Ok I'm done, I'll get off my resolution soapbox :)