def reaccumulate_flow(self):
"""Update drainage area, discharge, and upstream order.
Invoke the accumulator a second time to update drainage area,
discharge, and upstream order.
"""
# Calculate drainage area, discharge, and downstr->upstr order
Q_in = self._grid.at_node['water__volume_flux_in']
areas = self._grid.forced_cell_areas
self.a, q, s = flow_accum_bw.flow_accumulation(self.receivers,
np.where(self.sinks)[0],
node_cell_area=areas,
runoff_rate=Q_in)
# finish the property updating:
self._grid.at_node['drainage_area'][:] = self.a
self._grid.at_node['water__volume_flux'][:] = q
self._grid.at_node['upstream_ID_order'][:] = s
def reaccumulate_flow(self):
"""Update drainage area, discharge, and upstream order.
Invoke the accumulator a second time to update drainage area,
discharge, and upstream order.
"""
# Calculate drainage area, discharge, and downstr->upstr order
Q_in = self._grid.at_node["water__volume_flux_in"]
areas = self._grid.cell_area_at_node.copy()
areas[self._grid.closed_boundary_nodes] = 0.0
self.a, q, s = flow_accum_bw.flow_accumulation(
self.receivers, np.where(self.sinks)[0], node_cell_area=areas, runoff_rate=Q_in
)
# finish the property updating:
self._grid.at_node["drainage_area"][:] = self.a
self._grid.at_node["water__volume_flux"][:] = q
self._grid.at_node["upstream_node_order"][:] = s
def _reaccumulate_flow(self):
"""Update drainage area, discharge, and upstream order.
Invoke the accumulator a second time to update drainage area,
discharge, and upstream order.
"""
# Calculate drainage area, discharge, and downstr->upstr order
Q_in = self._grid.at_node['water__unit_flux_in']
areas = self._grid.cell_area_at_node.copy()
areas[self._grid.closed_boundary_nodes] = 0.
self.a, q, s = flow_accum_bw.flow_accumulation(self.receivers,
np.where(self.sinks)[0],
node_cell_area=areas,
runoff_rate=Q_in)
# finish the property updating:
self._grid.at_node['drainage_area'][:] = self.a
self._grid.at_node['water__discharge'][:] = q
self._grid.at_node['flow__upstream_node_order'][:] = s
def route_flow(self, **kwds):
"""Route surface-water flow over a landscape.
Routes surface-water flow by (1) assigning to each node a single
drainage direction, and then (2) adding up the number of nodes that
contribute flow to each node on the grid (including the node itself).
Stores as ModelGrid fields:
- Node array of receivers (nodes that receive flow), or ITS OWN ID if
there is no receiver: *'flow__receiver_node'*
- Node array of drainage areas: *'drainage_area'*
- Node array of discharges: *'surface_water__discharge'*
- Node array of steepest downhill slopes:
*'topographic__steepest_slope'*
- Node array containing downstream-to-upstream ordered list of node
IDs: *'flow__upstream_node_order'*
- Node array containing ID of link that leads from each node to its
receiver, or BAD_INDEX_VALUE if no link:
*'flow__link_to_receiver_node'*
- Boolean node array of all local lows: *'flow__sink_flag'*
Returns
-------
ModelGrid
The modified grid object
Examples
--------
>>> import numpy as np
>>> from landlab import RasterModelGrid
>>> from landlab.components.flow_routing import FlowRouter
>>> mg = RasterModelGrid((5, 4), spacing=(1, 1))
>>> elev = np.array([0., 0., 0., 0.,
... 0., 21., 10., 0.,
... 0., 31., 20., 0.,
... 0., 32., 30., 0.,
... 0., 0., 0., 0.])
>>> _ = mg.add_field('node','topographic__elevation', elev)
>>> mg.set_closed_boundaries_at_grid_edges(True, True, True, False)
>>> fr = FlowRouter(mg)
>>> mg = fr.route_flow()
>>> mg.at_node['flow__receiver_node'] # doctest: +NORMALIZE_WHITESPACE
array([ 0, 1, 2, 3,
4, 1, 2, 7,
8, 6, 6, 11,
12, 10, 10, 15,
16, 17, 18, 19])
>>> mg.at_node['drainage_area'] # doctest: +NORMALIZE_WHITESPACE
array([ 0., 1., 5., 0.,
0., 1., 5., 0.,
0., 1., 3., 0.,
0., 1., 1., 0.,
0., 0., 0., 0.])
Now let's change the cell area (100.) and the runoff rates:
>>> mg = RasterModelGrid((5, 4), spacing=(10., 10))
Put the data back into the new grid.
>>> _ = mg.add_field('node','topographic__elevation', elev)
>>> mg.set_closed_boundaries_at_grid_edges(True, True, True, False)
>>> fr = FlowRouter(mg)
>>> runoff_rate = np.arange(mg.number_of_nodes)
>>> _ = mg.add_field('node', 'water__unit_flux_in', runoff_rate,
... noclobber=False)
>>> mg = fr.route_flow()
>>> mg.at_node['surface_water__discharge'] # doctest: +NORMALIZE_WHITESPACE
array([ 0., 500., 5200., 0.,
0., 500., 5200., 0.,
0., 900., 3700., 0.,
0., 1300., 1400., 0.,
0., 0., 0., 0.])
"""
# this retained for back compatibility - method now set in __init__.
if 'method' in kwds:
warnings.warn("'method' should be set at initialization now. " +
"Please update your code.", DeprecationWarning)
# raise NameError
if kwds['method'] not in ('D8', 'D4'):
raise ValueError('method not understood ({method})'.format(
method=method))
else:
self.method = kwds['method']
if not self._is_raster:
self.method = None
if self._bc_set_code != self.grid.bc_set_code:
self.updated_boundary_conditions()
self._bc_set_code = self.grid.bc_set_code
# We assume that elevations are provided in a field called
# 'topographic__elevation'
elevs = self._grid['node']['topographic__elevation']
node_cell_area = self._grid.cell_area_at_node.copy()
node_cell_area[self._grid.closed_boundary_nodes] = 0.
# closed cells can't contribute
# Calculate the downhill-positive slopes at the d8 active links
if self.method == 'D8':
link_slope = - self._grid._calculate_gradients_at_d8_active_links(
elevs)
else:
link_slope = - self._grid.calc_grad_of_active_link(
elevs)
# Find the baselevel nodes
(baselevel_nodes, ) = numpy.where(
numpy.logical_or(self._grid.status_at_node == FIXED_VALUE_BOUNDARY,
self._grid.status_at_node == FIXED_GRADIENT_BOUNDARY))
# Calculate flow directions
if self.method == 'D4':
num_d4_active = self._grid.number_of_active_links # only d4
receiver, steepest_slope, sink, recvr_link = \
flow_direction_DN.flow_directions(elevs, self._active_links,
self._activelink_tail[:num_d4_active],
self._activelink_head[:num_d4_active],
link_slope,
grid=self._grid,
baselevel_nodes=baselevel_nodes)
else: # Voronoi or D8
receiver, steepest_slope, sink, recvr_link = \
flow_direction_DN.flow_directions(elevs, self._active_links,
self._activelink_tail,
self._activelink_head, link_slope,
grid=self._grid,
baselevel_nodes=baselevel_nodes)
# TODO: either need a way to calculate and return the *length* of the
# flow links, OR the caller has to handle the raster / non-raster case.
# Calculate drainage area, discharge, and ...
a, q, s = flow_accum_bw.flow_accumulation(
receiver, sink, node_cell_area=node_cell_area,
runoff_rate=self._grid.at_node['water__unit_flux_in'])
# added DEJH March 2014:
# store the generated data in the grid
self._grid['node']['drainage_area'][:] = a
self._grid['node']['flow__receiver_node'][:] = receiver
self._grid['node']['topographic__steepest_slope'][:] = steepest_slope
self._grid['node']['surface_water__discharge'][:] = q
self._grid['node']['flow__upstream_node_order'][:] = s
self._grid['node']['flow__link_to_receiver_node'][:] = recvr_link
self._grid['node']['flow__sink_flag'][:] = numpy.zeros_like(receiver,
dtype=bool)
self._grid['node']['flow__sink_flag'][sink] = True
return self._grid
def route_flow(self):
"""
Routes surface-water flow by (1) assigning to each node a single
drainage direction, and then (2) adding up the number of nodes that
contribute flow to each node on the grid (including the node itself).
Stores as ModelGrid fields:
- Node array of receivers (nodes that receive flow):
*'flow_receiver'*
- Node array of drainage areas: *'drainage_area'*
- Node array of discharges: *'water__volume_flux'*
- Node array of steepest downhill slopes: *'topographic__steepest_slope'*
- Node array containing downstream-to-upstream ordered list of node
IDs: *'upstream_ID_order'*
- Node array containing ID of link that leads from each node to its
receiver (or ITS OWN ID if there is no receiver):
*'links_to_flow_receiver'*
- Boolean node array of all local lows: *'flow_sinks'*
Returns:
- the modified grid object
Examples
--------
>>> import numpy as np
>>> from landlab import RasterModelGrid
>>> from landlab.components.flow_routing.route_flow_dn import FlowRouter
>>> mg = RasterModelGrid(5, 4, 1.0)
>>> elev = np.array([0., 0., 0., 0.,
... 0., 21., 10., 0.,
... 0., 31., 20., 0.,
... 0., 32., 30., 0.,
... 0., 0., 0., 0.])
>>> _ = mg.add_field('node','topographic__elevation', elev)
>>> mg.set_closed_boundaries_at_grid_edges(False, True, True, True)
>>> fr = FlowRouter(mg)
>>> mg = fr.route_flow()
>>> mg.at_node['flow_receiver']
array([ 0, 1, 2, 3, 4, 1, 2, 7, 8, 6, 6, 11, 12, 10, 10, 15, 16,
17, 18, 19])
>>> mg.at_node['drainage_area']
array([ 1., 2., 6., 1., 1., 1., 5., 1., 1., 1., 3., 1., 1.,
1., 1., 1., 1., 1., 1., 1.])
Now let's change the cell area and the runoff rates:
>>> mg = RasterModelGrid(5, 4, 10.) #so cell area==100.
>>> _ = mg.add_field('node','topographic__elevation', elev) #put the data back into the new grid
>>> mg.set_closed_boundaries_at_grid_edges(False, True, True, True)
>>> fr = FlowRouter(mg)
>>> runoff_rate = np.arange(mg.number_of_nodes)
>>> _ = mg.add_field('node', 'water__volume_flux_in', runoff_rate)
>>> mg = fr.route_flow()
>>> mg.at_node['water__volume_flux']
array([ 0., 600., 5400., 300., 400., 500., 5200., 700.,
800., 900., 3700., 1100., 1200., 1300., 1400., 1500.,
1600., 1700., 1800., 1900.])
"""
#if elevs is not provided, default to stored grid values, which must be provided as grid
elevs = self._grid['node'][self.value_field]
node_cell_area = self._grid.forced_cell_areas
# Calculate the downhill-positive slopes at the d8 active links
#TODO: generalize to use EITHER D8, if raster, or just active links,
# otherwise.
link_slope = -self._grid.calculate_gradients_at_d8_active_links(elevs)
# Find the baselevel nodes
(baselevel_nodes, ) = numpy.where(numpy.logical_or(self._grid.node_status==1, self._grid.node_status==2))
# Calculate flow directions
receiver, steepest_slope, sink, recvr_link = \
flow_direction_DN.flow_directions(elevs, self._active_links,
self._activelink_from,
self._activelink_to, link_slope,
grid=self._grid,
baselevel_nodes=baselevel_nodes)
#############grid=None???
# TODO: either need a way to calculate and return the *length* of the
# flow links, OR the caller has to handle the raster / non-raster case.
#print 'sinks:', sink
# Calculate drainage area, discharge, and ...
a, q, s = flow_accum_bw.flow_accumulation(receiver, sink,
node_cell_area=node_cell_area,
runoff_rate=self._grid.at_node['water__volume_flux_in'])
#added DEJH March 2014:
#store the generated data in the grid
self._grid['node']['drainage_area'] = a
self._grid['node']['flow_receiver'] = receiver
self._grid['node']['topographic__steepest_slope'] = steepest_slope
self._grid['node']['water__volume_flux'] = q
self._grid['node']['upstream_ID_order'] = s
self._grid['node']['links_to_flow_receiver'] = recvr_link
self._grid['node']['flow_sinks'] = numpy.zeros_like(receiver, dtype=bool)
self._grid['node']['flow_sinks'][sink] = True
return self._grid
def route_flow(self, elevs=None, grid=None, node_cell_area=1.0, runoff_rate=1.0,
boundary_nodes=None):
"""
Routes surface-water flow by (1) assigning to each node a single
drainage direction, and then (2) adding up the number of nodes that
contribute flow to each node on the grid (including the node itself).
If a scalar is specified for cell_area, computes the total surface
contributing area by assuming that each cell has the same surface area.
If an array is given (with length equal to the number of nodes), these
areas are used for each cell. Likewise, runoff_rate, in length per
time (volume per area per time) may be given either as a scalar
(identical for each cell) or as an array whose length is the number of
nodes in the grid.
Takes:
- Either *elevs*, an array of node elevations, or *grid*, a
reference to a ModelGrid.
Takes as optional inputs:
- *node_cell_area*, a float of the cell areas, if a raster, or
an array of the cell areas.
- *runoff_rate*, a float (for constant rainfall) or array (for
spatially variable rainfall) of runoff rates, such that drainage
area is in volume, rather than number of upstream cells.
Stores as ModelGrid fields, or returns, if *elevs* was provided rather
than *grid*:
- Node array of receivers (nodes that receive flow):
*'flow_receiver'*
- Node array of drainage areas: *'drainage_area'*
- Node array of discharges: *'water_discharges'*
- Node array of steepest downhill slopes: *'steepest_slope'*
- Node array containing downstream-to-upstream ordered list of node
IDs: *'upstream_ID_order'*
- Node array containing ID of link that leads from each node to its
receiver (or UNDEFINED_INDEX if there is no receiver):
*'links_to_flow_receiver'*
Returns, if *grid* was provided:
- the modified grid object
Example:
>>> from landlab import RasterModelGrid
>>> mg = RasterModelGrid(5, 4, 1.0)
>>> elev = numpy.array([0., 0., 0., 0.,
... 0., 21., 10., 0.,
... 0., 31., 20., 0.,
... 0., 32., 30., 0.,
... 0., 0., 0., 0.])
>>> mg.set_inactive_boundaries(False, True, True, True)
>>> fr = FlowRouter(mg)
>>> r, a, q, ss, s, rl = fr.route_flow(elevs=elev)
>>> r
array([ 0, 1, 2, 3, 4, 1, 2, 7, 8, 6, 6, 11, 12, 10, 10, 15, 16,
17, 18, 19])
>>> a
array([ 1., 2., 6., 1., 1., 1., 5., 1., 1., 1., 3., 1., 1.,
1., 1., 1., 1., 1., 1., 1.])
>>> r, a, q, ss, s, rl = fr.route_flow(elevs=elev, node_cell_area=10.0)
>>> a
array([ 10., 20., 60., 10., 10., 10., 50., 10., 10., 10., 30.,
10., 10., 10., 10., 10., 10., 10., 10., 10.])
>>> cell_areas = 10.0 + numpy.arange(mg.number_of_nodes)
>>> r, a, q, ss, s, rl = fr.route_flow(elevs=elev, node_cell_area=cell_areas)
>>> a
array([ 10., 26., 114., 13., 14., 15., 102., 17., 18.,
19., 67., 21., 22., 23., 24., 25., 26., 27.,
28., 29.])
>>> runoff_rate = numpy.arange(mg.number_of_nodes)
>>> r, a, q, ss, s, rl = fr.route_flow(elevs=elev, node_cell_area=100.0, runoff_rate=runoff_rate)
>>> q
array([ 0., 600., 5400., 300., 400., 500., 5200., 700.,
800., 900., 3700., 1100., 1200., 1300., 1400., 1500.,
1600., 1700., 1800., 1900.])
>>> r, a, q, ss, s, rl = fr.route_flow(elevs=elev, node_cell_area=cell_areas, runoff_rate=runoff_rate)
>>> q
array([ 0., 86., 1126., 39., 56., 75., 1102., 119.,
144., 171., 835., 231., 264., 299., 336., 375.,
416., 459., 504., 551.])
"""
#if elevs is not provided, default to stored grid values, which must be provided as grid
if elevs is None:
if grid is not None:
self._grid = grid
elevs = grid['node'][self.value_field]
else:
raise ValueError('Either an elevation array or a copy of the grid must be provided!')
try:
node_cell_area = self._grid.forced_cell_areas
except:
pass
# Calculate the downhill-positive slopes at the d8 active links
#TODO: generalize to use EITHER D8, if raster, or just active links,
# otherwise.
link_slope = -self._grid.calculate_gradients_at_d8_active_links(elevs)
# Find the baselevel nodes
(baselevel_nodes, ) = numpy.where( self._grid.node_status==1 )
# Calculate flow directions
receiver, steepest_slope, sink, recvr_link = \
flow_direction_DN.flow_directions(elevs, self._active_links, self._activelink_from,
self._activelink_to, link_slope,
grid=grid,
baselevel_nodes=baselevel_nodes)
#############grid=None???
# TODO: either need a way to calculate and return the *length* of the
# flow links, OR the caller has to handle the raster / non-raster case.
#print 'sinks:', sink
# Calculate drainage area, discharge, and ...
a, q, s = flow_accum_bw.flow_accumulation(receiver, sink,
node_cell_area, runoff_rate,
boundary_nodes)
#added DEJH March 2014:
#store the generated data in the grid
self._grid['node']['drainage_area'] = a
self._grid['node']['flow_receiver'] = receiver
self._grid['node']['steepest_slope'] = steepest_slope
self._grid['node']['water_discharges'] = q
self._grid['node']['upstream_ID_order'] = s
self._grid['node']['links_to_flow_receiver'] = recvr_link
if grid:
return self._grid
else:
return receiver, a, q, steepest_slope, s, recvr_link
def route_flow(self, **kwds):
"""Route surface-water flow over a landscape.
Routes surface-water flow by (1) assigning to each node a single
drainage direction, and then (2) adding up the number of nodes that
contribute flow to each node on the grid (including the node itself).
Stores as ModelGrid fields:
- Node array of receivers (nodes that receive flow), or ITS OWN ID if
there is no receiver: *'flow_receiver'*
- Node array of drainage areas: *'drainage_area'*
- Node array of discharges: *'water__volume_flux'*
- Node array of steepest downhill slopes:
*'topographic__steepest_slope'*
- Node array containing downstream-to-upstream ordered list of node
IDs: *'upstream_node_order'*
- Node array containing ID of link that leads from each node to its
receiver, or BAD_INDEX_VALUE if no link:
*'links_to_flow_receiver'*
- Boolean node array of all local lows: *'flow_sinks'*
Returns
-------
ModelGrid
The modified grid object
Examples
--------
>>> import numpy as np
>>> from landlab import RasterModelGrid
>>> from landlab.components.flow_routing import FlowRouter
>>> mg = RasterModelGrid((5, 4), spacing=(1, 1))
>>> elev = np.array([0., 0., 0., 0.,
... 0., 21., 10., 0.,
... 0., 31., 20., 0.,
... 0., 32., 30., 0.,
... 0., 0., 0., 0.])
>>> _ = mg.add_field('node','topographic__elevation', elev)
>>> mg.set_closed_boundaries_at_grid_edges(True, True, True, False)
>>> fr = FlowRouter(mg)
>>> mg = fr.route_flow()
>>> mg.at_node['flow_receiver'] # doctest: +NORMALIZE_WHITESPACE
array([ 0, 1, 2, 3,
4, 1, 2, 7,
8, 6, 6, 11,
12, 10, 10, 15,
16, 17, 18, 19])
>>> mg.at_node['drainage_area'] # doctest: +NORMALIZE_WHITESPACE
array([ 0., 1., 5., 0.,
0., 1., 5., 0.,
0., 1., 3., 0.,
0., 1., 1., 0.,
0., 0., 0., 0.])
Now let's change the cell area (100.) and the runoff rates:
>>> mg = RasterModelGrid((5, 4), spacing=(10., 10))
Put the data back into the new grid.
>>> _ = mg.add_field('node','topographic__elevation', elev)
>>> mg.set_closed_boundaries_at_grid_edges(True, True, True, False)
>>> fr = FlowRouter(mg)
>>> runoff_rate = np.arange(mg.number_of_nodes)
>>> _ = mg.add_field('node', 'water__unit_flux_in', runoff_rate,
... noclobber=False)
>>> mg = fr.route_flow()
>>> mg.at_node['water__volume_flux'] # doctest: +NORMALIZE_WHITESPACE
array([ 0., 500., 5200., 0.,
0., 500., 5200., 0.,
0., 900., 3700., 0.,
0., 1300., 1400., 0.,
0., 0., 0., 0.])
"""
# this retained for back compatibility - method now set in __init__.
if 'method' in kwds:
warnings.warn(
"'method' should be set at initialization now. " +
"Please update your code.", DeprecationWarning)
# raise NameError
if kwds['method'] not in ('D8', 'D4'):
raise ValueError(
'method not understood ({method})'.format(method=method))
else:
self.method = kwds['method']
if not self._is_raster:
self.method = None
# if elevs is not provided, default to stored grid values, which must
# be provided as grid
elevs = self._grid['node']['topographic__elevation']
node_cell_area = self._grid.cell_area_at_node.copy()
node_cell_area[self._grid.closed_boundary_nodes] = 0.
# closed cells can't contribute
# Calculate the downhill-positive slopes at the d8 active links
if self.method == 'D8':
link_slope = -self._grid.calculate_gradients_at_d8_active_links(
elevs)
else:
link_slope = -self._grid.calculate_gradients_at_active_links(elevs)
# Find the baselevel nodes
(baselevel_nodes, ) = numpy.where(
numpy.logical_or(self._grid.status_at_node == 1,
self._grid.status_at_node == 2))
# Calculate flow directions
if self.method == 'D4':
num_d4_active = self._grid.number_of_active_links # only d4
receiver, steepest_slope, sink, recvr_link = \
flow_direction_DN.flow_directions(elevs, self._active_links,
self._activelink_from[:num_d4_active],
self._activelink_to[:num_d4_active],
link_slope,
grid=self._grid,
baselevel_nodes=baselevel_nodes)
else: # Voronoi or D8
receiver, steepest_slope, sink, recvr_link = \
flow_direction_DN.flow_directions(elevs, self._active_links,
self._activelink_from,
self._activelink_to, link_slope,
grid=self._grid,
baselevel_nodes=baselevel_nodes)
# TODO: either need a way to calculate and return the *length* of the
# flow links, OR the caller has to handle the raster / non-raster case.
# Calculate drainage area, discharge, and ...
a, q, s = flow_accum_bw.flow_accumulation(
receiver,
sink,
node_cell_area=node_cell_area,
runoff_rate=self._grid.at_node['water__unit_flux_in'])
# added DEJH March 2014:
# store the generated data in the grid
self._grid['node']['drainage_area'][:] = a
self._grid['node']['flow_receiver'][:] = receiver
self._grid['node']['topographic__steepest_slope'][:] = steepest_slope
self._grid['node']['water__volume_flux'][:] = q
self._grid['node']['upstream_node_order'][:] = s
self._grid['node']['links_to_flow_receiver'][:] = recvr_link
self._grid['node']['flow_sinks'][:] = numpy.zeros_like(receiver,
dtype=bool)
self._grid['node']['flow_sinks'][sink] = True
return self._grid
def route_flow(self, method='D8'):
"""Route surface-water flow over a landscape.
Routes surface-water flow by (1) assigning to each node a single
drainage direction, and then (2) adding up the number of nodes that
contribute flow to each node on the grid (including the node itself).
Stores as ModelGrid fields:
- Node array of receivers (nodes that receive flow):
*'flow_receiver'*
- Node array of drainage areas: *'drainage_area'*
- Node array of discharges: *'water__volume_flux'*
- Node array of steepest downhill slopes:
*'topographic__steepest_slope'*
- Node array containing downstream-to-upstream ordered list of node
IDs: *'upstream_node_order'*
- Node array containing ID of link that leads from each node to its
receiver (or ITS OWN ID if there is no receiver):
*'links_to_flow_receiver'*
- Boolean node array of all local lows: *'flow_sinks'*
Parameters
----------
method : {'D8', 'D4'}, optional
Routing method ('D8' is the default). This keyword has no effect
for a Voronoi-based grid.
Returns
-------
ModelGrid
The modified grid object
Examples
--------
>>> import numpy as np
>>> from landlab import RasterModelGrid
>>> from landlab.components.flow_routing.route_flow_dn import FlowRouter
>>> mg = RasterModelGrid((5, 4), spacing=(1, 1))
>>> elev = np.array([0., 0., 0., 0.,
... 0., 21., 10., 0.,
... 0., 31., 20., 0.,
... 0., 32., 30., 0.,
... 0., 0., 0., 0.])
>>> _ = mg.add_field('node','topographic__elevation', elev)
>>> mg.set_closed_boundaries_at_grid_edges(False, True, True, True)
>>> fr = FlowRouter(mg)
>>> mg = fr.route_flow()
>>> mg.at_node['flow_receiver'] # doctest: +NORMALIZE_WHITESPACE
array([ 0, 1, 2, 3,
4, 1, 2, 7,
8, 6, 6, 11,
12, 10, 10, 15,
16, 17, 18, 19])
>>> mg.at_node['drainage_area'] # doctest: +NORMALIZE_WHITESPACE
array([ 0., 1., 5., 0.,
0., 1., 5., 0.,
0., 1., 3., 0.,
0., 1., 1., 0.,
0., 0., 0., 0.])
Now let's change the cell area (100.) and the runoff rates:
>>> mg = RasterModelGrid((5, 4), spacing=(10., 10))
Put the data back into the new grid.
>>> _ = mg.add_field('node','topographic__elevation', elev)
>>> mg.set_closed_boundaries_at_grid_edges(False, True, True, True)
>>> fr = FlowRouter(mg)
>>> runoff_rate = np.arange(mg.number_of_nodes)
>>> _ = mg.add_field('node', 'water__volume_flux_in', runoff_rate)
>>> mg = fr.route_flow()
>>> mg.at_node['water__volume_flux'] # doctest: +NORMALIZE_WHITESPACE
array([ 0., 500., 5200., 0.,
0., 500., 5200., 0.,
0., 900., 3700., 0.,
0., 1300., 1400., 0.,
0., 0., 0., 0.])
"""
if method not in ('D8', 'D4'):
raise ValueError('method not understood ({method})'.format(
method=method))
if not self._is_raster:
method = None
# if elevs is not provided, default to stored grid values, which must
# be provided as grid
elevs = self._grid['node'][self.value_field]
node_cell_area = self._grid.cell_area_at_node.copy()
node_cell_area[self._grid.closed_boundary_nodes] = 0.
# closed cells can't contribute
# Calculate the downhill-positive slopes at the d8 active links
if method == 'D8':
link_slope = - self._grid.calculate_gradients_at_d8_active_links(
elevs)
else:
link_slope = - self._grid.calculate_gradients_at_active_links(
elevs)
# Find the baselevel nodes
(baselevel_nodes, ) = numpy.where(
numpy.logical_or(self._grid.status_at_node == 1,
self._grid.status_at_node == 2))
# Calculate flow directions
if method == 'D4':
num_d4_active = self._grid.number_of_active_links # only d4
receiver, steepest_slope, sink, recvr_link = \
flow_direction_DN.flow_directions(elevs, self._active_links,
self._activelink_from[:num_d4_active],
self._activelink_to[:num_d4_active],
link_slope,
grid=self._grid,
baselevel_nodes=baselevel_nodes)
else: # Voronoi or D8
receiver, steepest_slope, sink, recvr_link = \
flow_direction_DN.flow_directions(elevs, self._active_links,
self._activelink_from,
self._activelink_to, link_slope,
grid=self._grid,
baselevel_nodes=baselevel_nodes)
#############grid=None???
# TODO: either need a way to calculate and return the *length* of the
# flow links, OR the caller has to handle the raster / non-raster case.
#print 'sinks:', sink
# Calculate drainage area, discharge, and ...
a, q, s = flow_accum_bw.flow_accumulation(
receiver, sink, node_cell_area=node_cell_area,
runoff_rate=self._grid.at_node['water__volume_flux_in'])
#added DEJH March 2014:
#store the generated data in the grid
self._grid['node']['drainage_area'] = a
self._grid['node']['flow_receiver'] = receiver
self._grid['node']['topographic__steepest_slope'] = steepest_slope
self._grid['node']['water__volume_flux'] = q
self._grid['node']['upstream_node_order'] = s
self._grid['node']['links_to_flow_receiver'] = recvr_link
self._grid['node']['flow_sinks'] = numpy.zeros_like(receiver,
dtype=bool)
self._grid['node']['flow_sinks'][sink] = True
return self._grid
