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IHydrologyOp.FlowDirection Method (ArcObjects .NET 10.5 SDK)
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ArcObjects Library Reference (SpatialAnalyst)  

IHydrologyOp.FlowDirection Method

Creates a raster of flow direction from each cell to it's steepest downslope neighbor.

[Visual Basic .NET]
Public Function FlowDirection ( _
    ByVal surfaceRaster As IGeoDataset, _
    ByVal createDrop As Boolean, _
    ByVal forceFlowAtEdge As Boolean _
) As IGeoDataset

[C#]
public IGeoDataset FlowDirection (
    IGeoDataset surfaceRaster,
    bool createDrop,
    bool forceFlowAtEdge
);

[C++]
HRESULT FlowDirection(
  IGeoDataset* surfaceRaster,
  VARIANT_BOOL createDrop,
  VARIANT_BOOL forceFlowAtEdge,
  IGeoDataset** FlowDirection
);

[C++]

Parameters
surfaceRaster [in]

  surfaceRaster is a parameter of type IGeoDataset
createDrop [in]
  createDrop is a parameter of type VARIANT_BOOL
forceFlowAtEdge [in]
  forceFlowAtEdge is a parameter of type VARIANT_BOOL
FlowDirection [out, retval]

  FlowDirection is a parameter of type IGeoDataset

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server. Requires Spatial Analyst Extension.

Remarks

surfaceRaster a raster representing an elevation surface
createDrop a Boolean that if set to True an optional output raster will be created showing a ratio of the maximum change in elevation from each cell along the direction of flow, to the path length between centers of cells, expressed in percents
forceFlowAtEdge controls the direction of flow at the edges of the surface raster

If the Boolean is set to True then the maximum drop on the inside of an edge cell if greater than zero, the flow direction will be determined as usual; otherwise, the flow direction will be toward the edge. Cells that should flow from the edge of the surface grid inward will do so.

If set to False, all cells at the edge of the surface surface will flow outward from the surface surface.

 

See Also

IHydrologyOp Interface