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SouthForkResearch / CHaMP_Metrics

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Bankfull Depth Max and Average #15

Open philipbaileynar opened 7 years ago

philipbaileynar commented 7 years ago

Revist how the python is doing this. Currently I think it's just reported values for the wetted extent depth raster.

volkcj commented 7 years ago

@philipbaileynar can you comment/confirm/update this issue?

volkcj commented 7 years ago

Bankfull Depth Avg and Bankfull Depth Max don't for RBT 6.0.04 and topo metric code 0.02 don't validate. Please revisit.

MattReimer commented 7 years ago

I think this is related to #80 which was fixed. If not then please reassign.

volkcj commented 7 years ago

I believe PB and I decided to make Bankfull Depth Avg and Bankfull Depth Max null since these are reading from the wetted raster. These currently still have values.

MattReimer commented 7 years ago

This has been fixed now I think:

<Wetted>
    <WaterExtent>
        <Area>1027.4622611</Area>
        <Depth>
            <Max>0.606628417969</Max>
            <Mean>0.187004723844</Mean>
        </Depth>
        <IntegratedWidth>5.02300014819</IntegratedWidth>
        <Volume>188.367988281</Volume>
    </WaterExtent>
</Wetted>
<Bankfull>
    <WaterExtent>
        <Area>2503.30595119</Area>
        <Depth>
            <Max/>
            <Mean/>
        </Depth>
        <IntegratedWidth>12.4318844119</IntegratedWidth>
        <Volume/>
    </WaterExtent>
</Bankfull>
philipbaileynar commented 6 years ago

Here is how we used to calculate those metrics in the past:

  1. Run ArcGIS ExtractValuesToPoints geoprocessing tool to find the average elevation of crew bankfull points in the detrended DEM.
  2. Run CreateConstantRaster geoprocessing tool to create a constant raster at this average detrended elevation.
  3. Re-introduce the trend to this constant raster (i.e. add the slope back in). The result is a modeled bankfull water surface.
  4. Subtract the raw DEM from the new bankfull water surface (use RasterCalculator geoprocessing tool for this step).
  5. Run SetNull geoprocessing tool on all negative values in the resultant raster to null. This produces a bankfull depth raster.
  6. Run ZonalStatisticsAsTable to get the metric values:
    1. Sum the bankfull depth raster values and multiply by the area of one cell to produce BFVol.
    2. Max the bankfull depth raster values is DepthBF_Max.
    3. Average the bankfull depth raster values is DepthBF_Avg