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U_INDEX - Percentage of all human land use

The U-Index (human use index) metric is the percentage of land cover cells located within the 3 km grid cell reporting unit that are classified as either agriculture, urban, or non-natural barren (transitional and mines/quarries) to the total number of cells inside the grid cell boundary minus those cells classified as water (total land area). This gives the proportion of land area in the grid cell that is influenced by human activity. High U-Index values depict areas in which land use practices could have profound effects on wildlife habitat, soil erosion and water quality. The values seen here are generally lower than in the central United States and areas along the eastern seaboard of the United States.