def test_mask_is_stable():
mg = RasterModelGrid((10, 10))
mg.add_zeros("node", "topographic__elevation")
np.random.seed(3542)
noise = np.random.rand(mg.size("node"))
mg.at_node["topographic__elevation"] += noise
fr = FlowAccumulator(mg, flow_director="D8")
fsc = FastscapeEroder(mg, K_sp=0.01, m_sp=0.5, n_sp=1)
for x in range(2):
fr.run_one_step()
fsc.run_one_step(dt=10.0)
mg.at_node["topographic__elevation"][mg.core_nodes] += 0.01
mask = np.zeros(len(mg.at_node["topographic__elevation"]), dtype=np.uint8)
mask[np.where(mg.at_node["drainage_area"] > 0)] = 1
mask0 = mask.copy()
dd = DrainageDensity(mg, channel__mask=mask)
mask1 = mask.copy()
dd.calc_drainage_density()
mask2 = mask.copy()
assert_array_equal(mask0, mask1)
assert_array_equal(mask0[mg.core_nodes], mask2[mg.core_nodes])
def CalandConv_DrainageDensity(rmg, DD_thrshld, filename):
rmg.at_node['topographic__elevation'][rmg.core_nodes]
channels = np.array(rmg.at_node['drainage_area'] > DD_thrshld,
dtype=np.uint8)
dd = DrainageDensity(rmg, channel__mask=channels)
mean_drainage_density = dd.calc_drainage_density()
print 'the mean drainage density of %s is: %f' % (filename,
mean_drainage_density)
return mean_drainage_density
