One of the more frequently misused terms in mapping specifications. According to the Glossary of Mapping Sciences (ASCE, ACSM, ASPRS, 1994), it is "a measure of the finest detail distinguishable in an image." While the distinguishable detail is dependent on the size of the image pixel, the size of an object that can be seen in an image and the size of a single pixel in an image are different.
Commonly, spatial resolution (the size of a pixel in an image) is confused with spatial accuracy (location of that pixel with reference to a mapping datum). To say that the size of a pixel in an image is 1 foot in ground units is not the same as saying that the ground coordinates of that pixel are accurate to within 1 foot of their "true value." An image can have very high spatial resolution and very low spatial accuracy, or vice versa.