ana5Utils.DFAPathGeneration.findFlowFront

findFlowFront(fieldPFT, demRaster, ftThreshold, lowFrontFraction)

locate the front of the deposit in a peak flow thickness field

The front is the flow-thickness-weighted centroid of the flow cells lying in the lowest lowFrontFraction of the flow elevation range. The band always contains the lowest flow cell; for a flat deposit it covers the whole footprint, so the front falls back to the centroid of the deposit. If the centroid falls outside the flow footprint (e.g. between two deposit lobes), the front is snapped to the nearest cell of the band.

Parameters

• fieldPFT (numpy array) – peak flow thickness field

• demRaster (numpy array) – dem raster of the same shape

• ftThreshold (float) – minimum flow thickness (m) for a cell to belong to the flow footprint

• lowFrontFraction (float) – fraction of the flow elevation range defining the front band

Returns

frontRow, frontCol – cell of the front, (None, None) if there is no flow above ftThreshold

Return type

int