def volume_spread(ldd,
hand,
subcatch,
volume,
volume_thres=0.,
area_multiplier=1.,
iterations=15):
"""
Estimate 2D flooding from a 1D simulation per subcatchment reach
Input:
ldd -- pcraster object direction, local drain directions
hand -- pcraster object float32, elevation data normalised to nearest drain
subcatch -- pcraster object ordinal, subcatchments with IDs
volume -- pcraster object float32, scalar flood volume (i.e. m3 volume outside the river bank within subcatchment)
volume_thres=0. -- scalar threshold, at least this amount of m3 of volume should be present in a catchment
area_multiplier=1. -- in case the maps are not in m2, set a multiplier other than 1. to convert
iterations=15 -- number of iterations to use
Output:
inundation -- pcraster object float32, scalar inundation estimate
"""
#initial values
pcr.setglobaloption("unittrue")
dem_min = pcr.areaminimum(hand,
subcatch) # minimum elevation in subcatchments
# pcr.report(dem_min, 'dem_min.map')
dem_norm = hand - dem_min
# pcr.report(dem_norm, 'dem_norm.map')
# surface of each subcatchment
surface = pcr.areaarea(subcatch) * area_multiplier
pcr.report(surface, 'surface.map')
error_abs = pcr.scalar(1e10) # initial error (very high)
volume_catch = pcr.areatotal(volume, subcatch)
# pcr.report(volume_catch, 'volume_catch.map')
depth_catch = volume_catch / surface
pcr.report(depth_catch, 'depth_catch.map')
dem_max = pcr.ifthenelse(volume_catch > volume_thres, pcr.scalar(32.),
pcr.scalar(0)) # bizarre high inundation depth
dem_min = pcr.scalar(0.)
for n in range(iterations):
print('Iteration: {:02d}'.format(n + 1))
#####while np.logical_and(error_abs > error_thres, dem_min < dem_max):
dem_av = (dem_min + dem_max) / 2
# pcr.report(dem_av, 'dem_av00.{:03d}'.format(n + 1))
# compute value at dem_av
average_depth_catch = pcr.areaaverage(pcr.max(dem_av - dem_norm, 0),
subcatch)
# pcr.report(average_depth_catch, 'depth_c0.{:03d}'.format(n + 1))
error = pcr.cover((depth_catch - average_depth_catch) / depth_catch,
depth_catch * 0)
# pcr.report(error, 'error000.{:03d}'.format(n + 1))
dem_min = pcr.ifthenelse(error > 0, dem_av, dem_min)
dem_max = pcr.ifthenelse(error <= 0, dem_av, dem_max)
# error_abs = np.abs(error) # TODO: not needed probably, remove
inundation = pcr.max(dem_av - dem_norm, 0)
return inundation
def volume_spread(ldd,
hand,
subcatch,
volume,
volume_thres=0.,
cell_surface=1.,
iterations=15,
logging=logging,
order=0):
"""
Estimate 2D flooding from a 1D simulation per subcatchment reach
Input:
ldd -- pcraster object direction, local drain directions
hand -- pcraster object float32, elevation data normalised to nearest drain
subcatch -- pcraster object ordinal, subcatchments with IDs
volume -- pcraster object float32, scalar flood volume (i.e. m3 volume outside the river bank within subcatchment)
volume_thres=0. -- scalar threshold, at least this amount of m3 of volume should be present in a catchment
area_multiplier=1. -- in case the maps are not in m2, set a multiplier other than 1. to convert
iterations=15 -- number of iterations to use
Output:
inundation -- pcraster object float32, scalar inundation estimate
"""
#initial values
pcr.setglobaloption("unitcell")
dem_min = pcr.areaminimum(hand,
subcatch) # minimum elevation in subcatchments
dem_norm = hand - dem_min
# surface of each subcatchment
surface = pcr.areaarea(subcatch) * pcr.areaaverage(
cell_surface, subcatch) # area_multiplier
error_abs = pcr.scalar(1e10) # initial error (very high)
volume_catch = pcr.areatotal(volume, subcatch)
depth_catch = volume_catch / surface # meters water disc averaged over subcatchment
# ilt(depth_catch, 'depth_catch_{:02d}.map'.format(order))
# pcr.report(volume, 'volume_{:02d}.map'.format(order))
dem_max = pcr.ifthenelse(volume_catch > volume_thres, pcr.scalar(32.),
pcr.scalar(0)) # bizarre high inundation depth
dem_min = pcr.scalar(0.)
for n in range(iterations):
logging.debug('Iteration: {:02d}'.format(n + 1))
#####while np.logical_and(error_abs > error_thres, dem_min < dem_max):
dem_av = (dem_min + dem_max) / 2
# compute value at dem_av
average_depth_catch = pcr.areaaverage(pcr.max(dem_av - dem_norm, 0),
subcatch)
error = pcr.cover((depth_catch - average_depth_catch) / depth_catch,
depth_catch * 0)
dem_min = pcr.ifthenelse(error > 0, dem_av, dem_min)
dem_max = pcr.ifthenelse(error <= 0, dem_av, dem_max)
inundation = pcr.max(dem_av - dem_norm, 0)
pcr.setglobaloption('unittrue')
return inundation
def volume_spread(ldd, hand, subcatch, volume, volume_thres=0., area_multiplier=1., iterations=15):
"""
Estimate 2D flooding from a 1D simulation per subcatchment reach
Input:
ldd -- pcraster object direction, local drain directions
hand -- pcraster object float32, elevation data normalised to nearest drain
subcatch -- pcraster object ordinal, subcatchments with IDs
volume -- pcraster object float32, scalar flood volume (i.e. m3 volume outside the river bank within subcatchment)
volume_thres=0. -- scalar threshold, at least this amount of m3 of volume should be present in a catchment
area_multiplier=1. -- in case the maps are not in m2, set a multiplier other than 1. to convert
iterations=15 -- number of iterations to use
Output:
inundation -- pcraster object float32, scalar inundation estimate
"""
#initial values
pcr.setglobaloption("unittrue")
dem_min = pcr.areaminimum(hand, subcatch) # minimum elevation in subcatchments
# pcr.report(dem_min, 'dem_min.map')
dem_norm = hand - dem_min
# pcr.report(dem_norm, 'dem_norm.map')
# surface of each subcatchment
surface = pcr.areaarea(subcatch)*area_multiplier
pcr.report(surface, 'surface.map')
error_abs = pcr.scalar(1e10) # initial error (very high)
volume_catch = pcr.areatotal(volume, subcatch)
# pcr.report(volume_catch, 'volume_catch.map')
depth_catch = volume_catch/surface
pcr.report(depth_catch, 'depth_catch.map')
dem_max = pcr.ifthenelse(volume_catch > volume_thres, pcr.scalar(32.),
pcr.scalar(0)) # bizarre high inundation depth
dem_min = pcr.scalar(0.)
for n in range(iterations):
print('Iteration: {:02d}'.format(n + 1))
#####while np.logical_and(error_abs > error_thres, dem_min < dem_max):
dem_av = (dem_min + dem_max)/2
# pcr.report(dem_av, 'dem_av00.{:03d}'.format(n + 1))
# compute value at dem_av
average_depth_catch = pcr.areaaverage(pcr.max(dem_av - dem_norm, 0), subcatch)
# pcr.report(average_depth_catch, 'depth_c0.{:03d}'.format(n + 1))
error = pcr.cover((depth_catch-average_depth_catch)/depth_catch, depth_catch*0)
# pcr.report(error, 'error000.{:03d}'.format(n + 1))
dem_min = pcr.ifthenelse(error > 0, dem_av, dem_min)
dem_max = pcr.ifthenelse(error <= 0, dem_av, dem_max)
# error_abs = np.abs(error) # TODO: not needed probably, remove
inundation = pcr.max(dem_av - dem_norm, 0)
return inundation
def volume_spread(ldd, hand, subcatch, volume, volume_thres=0., cell_surface=1., iterations=15, logging=logging, order=0, neg_HAND=None):
"""
Estimate 2D flooding from a 1D simulation per subcatchment reach
Input:
ldd -- pcraster object direction, local drain directions
hand -- pcraster object float32, elevation data normalised to nearest drain
subcatch -- pcraster object ordinal, subcatchments with IDs
volume -- pcraster object float32, scalar flood volume (i.e. m3 volume outside the river bank within subcatchment)
volume_thres=0. -- scalar threshold, at least this amount of m3 of volume should be present in a catchment
area_multiplier=1. -- in case the maps are not in m2, set a multiplier other than 1. to convert
iterations=15 -- number of iterations to use
neg_HAND -- if set to 1, HAND maps can have negative values when elevation outside of stream is lower than
stream (for example when there are natural embankments)
Output:
inundation -- pcraster object float32, scalar inundation estimate
"""
#initial values
pcr.setglobaloption("unitcell")
dem_min = pcr.areaminimum(hand, subcatch) # minimum elevation in subcatchments
dem_norm = hand - dem_min
# surface of each subcatchment
surface = pcr.areaarea(subcatch)*pcr.areaaverage(cell_surface, subcatch) # area_multiplier
error_abs = pcr.scalar(1e10) # initial error (very high)
volume_catch = pcr.areatotal(volume, subcatch)
depth_catch = volume_catch/surface # meters water disc averaged over subcatchment
# ilt(depth_catch, 'depth_catch_{:02d}.map'.format(order))
# pcr.report(volume, 'volume_{:02d}.map'.format(order))
if neg_HAND == 1:
dem_max = pcr.ifthenelse(volume_catch > volume_thres, pcr.scalar(32.),
pcr.scalar(-32.)) # bizarre high inundation depth☻
dem_min = pcr.scalar(-32.)
else:
dem_max = pcr.ifthenelse(volume_catch > volume_thres, pcr.scalar(32.),
pcr.scalar(0.)) # bizarre high inundation depth☻
dem_min = pcr.scalar(0.)
for n in range(iterations):
logging.debug('Iteration: {:02d}'.format(n + 1))
#####while np.logical_and(error_abs > error_thres, dem_min < dem_max):
dem_av = (dem_min + dem_max)/2
# compute value at dem_av
average_depth_catch = pcr.areaaverage(pcr.max(dem_av - dem_norm, 0), subcatch)
error = pcr.cover((depth_catch-average_depth_catch)/depth_catch, depth_catch*0)
dem_min = pcr.ifthenelse(error > 0, dem_av, dem_min)
dem_max = pcr.ifthenelse(error <= 0, dem_av, dem_max)
inundation = pcr.max(dem_av - dem_norm, 0)
pcr.setglobaloption('unittrue')
return inundation