For an input D-Infinity flow direction raster, a cell is considered to have an undefined flow direction if its value in the flow direction raster is -1. A sample usage of the Flow Accumulation tool with an input weight raster might be to determine how much rain has fallen within a given watershed. By applying a threshold value to the results of the Flow Accumulation tool using either the Con or Set Null tools, a stream network can be delineated. The output raster that shows the accumulated flow to each cell. By default, this tool will use 50 percent of the available cores. The result of Flow Accumulation is a raster of accumulated flow to each cell, as determined by accumulating the weight for all cells that flow into each downslope cell.. Verwendung. Cells with a flow accumulation of 0 are local topographic highs and may be used to identify ridges. Learn more about how Flow Accumulation works. If no weight raster is provided, a weight of one is applied to each cell, and the value of cells in the output raster will be the number of cells that flow into each cell. DINF —The input flow direction raster is of type D-Infinity (DINF). The problem is that there is no tutorial about how the implementation works in ArcGIS ... To calculate the LS factor for the RUSLE equation, first calculate flow accumulation (facc) and slope in degrees (slp). The default temp folder location will be on your local C drive. Output cells with a flow accumulation of zero are local topographic highs and can be used to identify ridges. Dies kann auch als die Niederschlagsmenge bezeichnet werden, die auf der Oberfläche auf höher gelegenen Flächen von den einzelnen Zellen auftraf. Procedure. The data has been through a "fill" procedure once. A sample usage of the Flow Accumulation tool with an input weight raster might be to determine how much rain has fallen within a given watershed. Calculating the direction of flow. The input flow direction raster can be of type D8, Multi Flow Direction (MFD) or D-Infinity (DINF). New software can provide more accurate hydrologic information than other commercial GIS software such as IDRISI and ArcGIS. Learn more about how Flow Accumulation works. The result of Flow Accumulation is a raster of accumulated flow to each cell, as determined by accumulating the weight for all cells that flow into each downslope cell.. You can control the location of this folder by setting up a system environment variable named TempFolders and specifying the path to a folder to use (for example, E:\RasterCache). Use the flow_direction_type parameter to specify which method was used when the flow direction raster was created. In general, Flow Accumulation value (at pour point A) = cell count of Watershed for pour point A - 1. Raster data, such as DEMs, can be converted to vector datasets to increase analytical capabilities. For each cell in the output raster, the result will be the number of cells that flow into it. The Flow Accumulation function calculates accumulated flow as the accumulated weight of all cells flowing into each downslope cell in the output raster. 1988. Here is a quick overview of the steps for delineating a watershed in ArcGIS – we have detailed directions later. Usage. See Analysis environments and Spatial Analyst for additional details on the geoprocessing environments that apply to this tool. Das Ergebnis von Flow Accumulation ist ein Raster der Abflussakkumulation zu jeder Zelle, wie durch das Akkumulieren der Gewichtung für alle Zellen, die in die einzelnen tiefer gelegenen Zelle fließen, bestimmt.. Zellen mit nicht definierter Fließrichtung erhalten nur Fluss; sie tragen nicht zum Wasserstrom flussabwärts bei. Calculating the flow accumulation at point O seems straight forward with a hydrologic model, but I support you in that the calculations you are trying to make are difficult. The Flow Accumulation tool supports three flow modeling algorithms while computing accumulated flow. ArcGIS can compute from the DEM the direction of flow down a slope and how many cells “flow into” each cell (called flow accumulation). Now I am making my own algorithm and R codes that calculate flow accumulation based on flow direction, and the test of the codes and algorithm will be done in a couple of months.