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Sink results in very different demarkations?

Question asked by JB1234510 on Apr 8, 2020
Latest reply on Apr 9, 2020 by nnoman-esristaff

Sink results in very different demarkations depending on the resampling of the raster data. Could someone explain why? I don't understand this?

In the attached images you could see the differences. I use elevation data with a resolution of 5 meters. Sink06m ... is in my opinion better because nearly all lakes are demarked as sinks. Sink06m is resampled to a cellsize of 6m biliniear. Sink10m is resampled to a cellsize 10 meters, but the results are totally different?

Am I doing something wrong?

 

This is how I calculated the areas:

 

import arcpy, os
from arcpy.sa import *

arcpy.env.overwriteOutput = True

arcpy.env.workspace = r"MyPath\DGM.gdb"

# Local variables:
DGM005_tif = r"MyPath\DGM005_3.tif"
Fill_tif1 = "Fill_1"
resample = "resample"
FlowDir_Fill2 = "FlowDir_1"
Sink_FlowDir1 = "Sink_FlowDir1"
absenkung = "Absenkung"

arcpy.CheckOutExtension("Spatial")

outCon2 = Con(Raster(DGM005_tif) > 0, DGM005_tif)

# Process: Füllung
arcpy.gp.Fill_sa(outCon2, Fill_tif1, "")
print("fill")

arcpy.Resample_management(Fill_tif1, resample, "8", "BILINEAR")
print("resample")

# Process: Fließrichtung
arcpy.gp.FlowDirection_sa(resample, FlowDir_Fill2, "NORMAL", absenkung)
print("flowdir")

# Process: Senke
arcpy.gp.Sink_sa(FlowDir_Fill2, Sink_FlowDir1)
print("sink")

arcpy.RasterToPolygon_conversion(Sink_FlowDir1, "{}{}".format("Senke08mfill", os.path.basename(os.path.splitext(DGM005_tif)[0])), "SIMPLIFY",
                                  "VALUE")
print("Done")

arcpy.CheckInExtension("Spatial")

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