Units Per Pixel

UPP or Units per Pixel determine the resolution factor. This determines how many measuring units (kilometers, miles, meters etc.) each pixel represents. A higher resolution means fewer units per pixel (a low UPP) and a sharper image or elevation distinction.

A view from far away or very high up covers a larger area but is represented in the same size frame so every pixel represents a larger number of measured units. Therefore the resolution is lower, the UPP is higher and the image or resolution is duller.

TerraBuilder uses resolution pyramids, which are files that contain one source (image or elevation) in several resolutions.