Spatial Resolution

Spatial resolution The column (C) by row (R) dimensions of the image define the number of pixels used to cover the visual space captured by the image.This relates to the sampling of the image signal and is sometimes referred to as the pixel or digital resolution of the image. It is commonly quoted as CR (e.g. 640x480, 800x600, 1024x768, etc.)
The spatial resolution of computer monitors is generally 72 to 100 lines per inch, corresponding to pixel resolutions of 72 to 100 ppi. With scanners, optical resolution is sometimes used to distinguish spatial resolution from the number of pixels per inch.
In remote sensing, spatial resolution is typically limited by diffraction, as well as by aberrations, imperfect focus, and atmospheric distortion. The ground sample distance (GSD) of an image, the pixel spacing on the Earth’s surface, is typically considerably smaller than the resolvable spot size.
Consider the following image. In this images, image at left has a higher pixel count than the one to the right, but is still of worse spatial resolution.