topic Flow direction when there are cells with the same change in Z in multiple directions? in ArcGIS Spatial Analyst Questions https://community.esri.com/t5/arcgis-spatial-analyst-questions/flow-direction-when-there-are-cells-with-the-same/m-p/388968#M5470 <HTML><HEAD></HEAD><BODY><SPAN>Hi</SPAN><BR /><SPAN>I have a DTM that I have filled with the Fill-tool (The depression is filled up to 9,90 m) and then used to to calculate flow directions with spatial analyst, ArcMap 10.0.</SPAN><BR /><BR /><SPAN>In the DTM there are cells with same change in z-value in multiple directions and these are not part of a sink. According to ArcMap 10.0 help "the flow direction is assigned with a lookup table defining the most likely direction. See Greenlee (1987)", but unfortunately I don't have access to Greenlee 1987 (Greenlee, D. D. 1987. "Raster and Vector Processing for Scanned Linework." Photogrammetric Engineering and Remote Sensing 53 (10): 1383???1387).</SPAN><BR /><BR /><SPAN>I have attached a picture of my DTM with elevation and the derived flow direction, I would like to know if anyone know why the directions are assigned how the are for the red arrows???</SPAN><BR /><BR /><SPAN>Thanks in advance,</SPAN><BR /><SPAN>Mie</SPAN><BR /><SPAN>University of Copenhagen</SPAN></BODY></HTML> Mon, 18 Mar 2013 12:15:28 GMT miewinstrup 2013-03-18T12:15:28Z Flow direction when there are cells with the same change in Z in multiple directions? https://community.esri.com/t5/arcgis-spatial-analyst-questions/flow-direction-when-there-are-cells-with-the-same/m-p/388968#M5470 <HTML><HEAD></HEAD><BODY><SPAN>Hi</SPAN><BR /><SPAN>I have a DTM that I have filled with the Fill-tool (The depression is filled up to 9,90 m) and then used to to calculate flow directions with spatial analyst, ArcMap 10.0.</SPAN><BR /><BR /><SPAN>In the DTM there are cells with same change in z-value in multiple directions and these are not part of a sink. According to ArcMap 10.0 help "the flow direction is assigned with a lookup table defining the most likely direction. See Greenlee (1987)", but unfortunately I don't have access to Greenlee 1987 (Greenlee, D. D. 1987. "Raster and Vector Processing for Scanned Linework." Photogrammetric Engineering and Remote Sensing 53 (10): 1383???1387).</SPAN><BR /><BR /><SPAN>I have attached a picture of my DTM with elevation and the derived flow direction, I would like to know if anyone know why the directions are assigned how the are for the red arrows???</SPAN><BR /><BR /><SPAN>Thanks in advance,</SPAN><BR /><SPAN>Mie</SPAN><BR /><SPAN>University of Copenhagen</SPAN></BODY></HTML> Mon, 18 Mar 2013 12:15:28 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/flow-direction-when-there-are-cells-with-the-same/m-p/388968#M5470 miewinstrup 2013-03-18T12:15:28Z