Final answer:
The ground size of one pixel's worth of imagery is measured by resolution, which is the number of pixels used to make a photo. The higher the resolution, the more detail and sharpness the image will have.
Step-by-step explanation:
The ground size of one pixel's worth of imagery is a measure of resolution. Resolution is a measure of the number of pixels used to make a photo. The more pixels there are, the higher the resolution and the sharper the image. In the case of digital photos, the resolution is usually measured in megapixels.
To calculate the photo size in megapixels, you multiply the photo's pixel width by the pixel height and divide by one million. For example, a photo with dimensions of 640 x 480 pixels would have a resolution of 0.3 megapixels.
Therefore, the ground size of one pixel's worth of imagery refers to the level of detail or sharpness that can be captured by a single pixel in an image.