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Elevation Derivatives for National Applications (EDNA)



EDNA Stage 1 Data Layers

Flow Accumulation (5K)

Flow Accumulation

File Type:   Grid -Floating Point

Valid values:
    Threshold value:   5000 cells,
    Maximum value:    231 or 2.147 gb
    (mouth of Mississippi River)
Description: Represents the number of upstream cells that flow to a specific cell. Each cell is assigned a value that is the sum of all the cells that contribute flow to the cell. Generated from the flow direction grid using the 'flowaccumulation' function. Threshold values are closely related to network density. The higher the threshold value, the lower the network density and the lower the threshold value, the higher the network density. In this project the threshold value for flow accumulation required to begin a synthetic streamline was set to 5000 cells.

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Page Last Modified: May 25, 2005