def calc_slope(elevation):
"""Calculates slope angle in percent using r.slope.aspect
Parameters
----------
elevation : str
Name of the GRASS raster map with the elevation data.
Returns
-------
slope : str
Name of the output slope map.
"""
slope = rand_id("slope{}".format(L + 1))
TMP_RAST[L].append(slope)
r.slope_aspect(elevation=elevation,
slope=slope,
flags="e",
format="percent",
quiet=True)
return slope
def main():
# user specified variables
dem = options["elevation"]
slope = options["slope"]
aspect = options["aspect"]
neighborhood_size = options["size"]
output = options["output"]
nprocs = int(options["nprocs"])
exponent = float(options["exponent"])
# check for valid neighborhood sizes
neighborhood_size = neighborhood_size.split(",")
neighborhood_size = [int(i) for i in neighborhood_size]
if any([True for i in neighborhood_size if i % 2 == 0]):
gs.fatal(
"Invalid size - neighborhood sizes have to consist of odd numbers")
if min(neighborhood_size) == 1:
gs.fatal("Neighborhood sizes have to be > 1")
# determine nprocs
if nprocs < 0:
n_cores = mp.cpu_count()
nprocs = n_cores - (nprocs + 1)
# temporary raster map names for slope, aspect, x, y, z components
if slope == "":
slope_raster = create_tempname("tmpSlope_")
else:
slope_raster = slope
if aspect == "":
aspect_raster = create_tempname("tmpAspect_")
else:
aspect_raster = aspect
z_raster = create_tempname("tmpzRaster_")
x_raster = create_tempname("tmpxRaster_")
y_raster = create_tempname("tmpyRaster_")
# create slope and aspect rasters
if slope == "" or aspect == "":
gs.message("Calculating slope and aspect...")
gr.slope_aspect(
elevation=dem,
slope=slope_raster,
aspect=aspect_raster,
format="degrees",
precision="FCELL",
zscale=1.0,
min_slope=0.0,
quiet=True,
)
# calculate x y and z rasters
# note - GRASS sin/cos functions differ from ArcGIS which expects input grid in radians
# whereas GRASS functions expect degrees
# no need to convert slope and aspect to radians as in the original ArcGIS script
x_expr = "{x} = float( sin({a}) * sin({b}) )".format(x=x_raster,
a=aspect_raster,
b=slope_raster)
y_expr = "{y} = float( cos({a}) * sin({b}) )".format(y=y_raster,
a=aspect_raster,
b=slope_raster)
z_expr = "{z} = float( cos({a}) )".format(z=z_raster, a=slope_raster)
# calculate x, y, z components (parallel)
gs.message("Calculating x, y, and z rasters...")
mapcalc = Module("r.mapcalc", run_=False)
queue = ParallelModuleQueue(nprocs=nprocs)
mapcalc1 = copy.deepcopy(mapcalc)
m = mapcalc1(expression=x_expr)
queue.put(m)
mapcalc2 = copy.deepcopy(mapcalc)
m = mapcalc2(expression=y_expr)
queue.put(m)
mapcalc3 = copy.deepcopy(mapcalc)
m = mapcalc3(expression=z_expr)
queue.put(m)
queue.wait()
# calculate x, y, z neighborhood sums (parallel)
gs.message(
"Calculating sums of x, y, and z rasters in selected neighborhoods...")
x_sum_list = []
y_sum_list = []
z_sum_list = []
neighbors = Module("r.neighbors", overwrite=True, run_=False)
queue = ParallelModuleQueue(nprocs=nprocs)
for size in neighborhood_size:
# create temporary raster names for neighborhood x, y, z sums
x_sum_raster = create_tempname("tmpxSumRaster_")
x_sum_list.append(x_sum_raster)
y_sum_raster = create_tempname("tmpySumRaster_")
y_sum_list.append(y_sum_raster)
z_sum_raster = create_tempname("tmpzSumRaster_")
z_sum_list.append(z_sum_raster)
# create weights
mat = idw_weights(size, exponent)
# queue jobs for x, y, z neighborhood sums
neighbors_xsum = copy.deepcopy(neighbors)
n = neighbors_xsum(
input=x_raster,
output=x_sum_raster,
method="average",
size=size,
weight=mat,
stdin=mat,
)
queue.put(n)
neighbors_ysum = copy.deepcopy(neighbors)
n = neighbors_ysum(
input=y_raster,
output=y_sum_raster,
method="average",
size=size,
weight=mat,
)
queue.put(n)
neighbors_zsum = copy.deepcopy(neighbors)
n = neighbors_zsum(
input=z_raster,
output=z_sum_raster,
method="average",
size=size,
weight=mat,
)
queue.put(n)
queue.wait()
# calculate the resultant vector and final ruggedness raster
# modified from the original script to multiple each SumRaster by the n neighborhood
# cells to get the sum
gs.message("Calculating the final ruggedness rasters...")
mapcalc = Module("r.mapcalc", run_=False)
queue = ParallelModuleQueue(nprocs=nprocs)
vrm_list = []
for x_sum_raster, y_sum_raster, z_sum_raster, size in zip(
x_sum_list, y_sum_list, z_sum_list, neighborhood_size):
if len(neighborhood_size) > 1:
vrm_name = "_".join([output, str(size)])
else:
vrm_name = output
vrm_list.append(vrm_name)
vrm_expr = "{x} = float(1-( (sqrt(({a}*{d})^2 + ({b}*{d})^2 + ({c}*{d})^2) / {d})))".format(
x=vrm_name,
a=x_sum_raster,
b=y_sum_raster,
c=z_sum_raster,
d=int(size) * int(size),
)
mapcalc1 = copy.deepcopy(mapcalc)
m = mapcalc1(expression=vrm_expr)
queue.put(m)
queue.wait()
# set colors
gr.colors(flags="e", map=vrm_list, color="ryb")
# set metadata
for vrm, size in zip(vrm_list, neighborhood_size):
title = "Vector Ruggedness Measure (size={size})".format(size=size)
gr.support(map=vrm, title=title)
return 0
streams=streams_all,
streams_modflow=streams_MODFLOW,
dem_modflow=DEM_MODFLOW,
overwrite=True)
# GSFLOW reaches: intersection of segments and grid
v.gsflow_reaches(segment_input=segments,
grid_input=MODFLOW_grid,
elevation=DEM,
output=reaches,
overwrite=True)
# GSFLOW HRU parameters
r.slope_aspect(elevation=DEM,
slope=slope,
aspect=aspect,
format='percent',
zscale=0.01,
overwrite=True)
v.gsflow_hruparams(input=basins_inbasin,
elevation=DEM,
output=HRUs,
slope=slope,
aspect=aspect,
overwrite=True)
# GSFLOW gravity reservoirs
v.gsflow_gravres(hru_input=HRUs,
grid_input=MODFLOW_grid,
output=gravity_reservoirs,
overwrite=True)
* chi?
* remember, these are meant to work ASSUMING STREAM POWER
--> and therefore probably assuming bedrock, though all quite
fuzzy in stream-power land anyway.
"""
# Full set of commands:
elevation = 'srtm3'
#slope = 'srtm.slope'
#streams = 'srtm.stream
# or THRESH if not STREAMS -- in km**2
thresh = 10 # 1 km2 = minimum catchment size
# Made to work on a projected coordinate system PROJECTED!
reg = region.Region()
"""
# Slope first, easy
r.slope_aspect(elevation=elevation, slope='tmp', format='percent', overwrite=True)
r.mapcalc('slope = tmp/100.', overwrite=True)
# Assuming you work in meters. ASSUMING!
# Have to include output name or write to a temporary file, FOR ALL!
r.mapcalc('cellArea_meters2 = '+str(reg.nsres)+' * '+str(reg.ewres), overwrite=True)
r.mapcalc("cellArea_km2 = cellArea_meters2 / 10^6", overwrite=True)
# Works with MFD too!
# Not really. Drainage from one catchment goes to multiple basins
r.watershed(elevation=elevation, flow='cellArea_km2', accumulation='drainageArea_km2', drainage='drainageDirection', stream='streams_tmp', threshold=thresh, flags='s', overwrite=True)
# Remove areas of negative (offmap) accumulation
r.mapcalc('drainageArea_km2 = drainageArea_km2 * (drainageArea_km2 > 0)', overwrite=True)
r.null(map='drainageArea_km2', setnull=0)
# or THRESH if not STREAMS -- in km**2
thresh = 0.2 # 10 km2 = minimum catchment size
thresh = 10000 # m2
# Made to work on a projected coordinate system PROJECTED!
reg = region.Region()
##############
# BEFOREHAND #
##############
# These also will generate inputs: code to run beforehand
# Slope first, easy
print "Computing slope with r.slope.aspect. Slope in unitless decimal values."
r.slope_aspect(elevation=elevation,
slope='tmp',
format='percent',
overwrite=True)
r.mapcalc('slope = tmp/100.', overwrite=True)
# Assuming you work in meters. ASSUMING!
# Have to include output name or write to a temporary file, FOR ALL!
r.mapcalc('cellArea_meters2 = ' + str(reg.nsres) + ' * ' + str(reg.ewres),
overwrite=True)
r.mapcalc("cellArea_km2 = cellArea_meters2 / 10^6", overwrite=True)
print "Running r.watershed"
r.watershed(elevation=elevation,
flow='cellArea_meters2',
accumulation='drainageArea_m2',
drainage='drainageDirection',
stream='streams',
from mower import GrassSession
DEM = "/home/mperry/projects/shortcreek/dem/dem.img"
with GrassSession(DEM) as gs:
from grass.pygrass.modules.shortcuts import raster
# Import/Link to External GDAL data
raster.external(input=DEM, output="dem")
# Perform calculations
raster.mapcalc(expression="demft=dem*3.28084")
raster.slope_aspect(elevation="demft", slope="slope", aspect="aspect")
# Export from GRASS to GDAL
from grass.pygrass.gis import Mapset
m = Mapset()
for r in m.glist('rast'):
if r == "dem":
# don't save the original
continue
raster.out_gdal(r, format="GTiff", output="/tmp/{}.tif".format(r), overwrite=True)
def slopestats():
slopemap = Rast(maps['elevation'].name + '.slope')
r.slope_aspect(elevation=maps['elevation'].name, slope=slopemap.name, format='percent')
print('\n \n Statistics for slope <%s> (slope in %%): '%(slopemap.name))
rsoillossstats(soilloss=slopemap.name, map=parcelmap.name, parcelnumcol='id')
from mower import GrassSession
DEM = "/home/mperry/projects/shortcreek/dem/dem.img"
with GrassSession(DEM) as gs:
from grass.pygrass.modules.shortcuts import raster
# Import/Link to External GDAL data
raster.external(input=DEM, output="dem")
# Perform calculations
raster.mapcalc(expression="demft=dem*3.28084")
raster.slope_aspect(elevation="demft", slope="slope", aspect="aspect")
# Export from GRASS to GDAL
from grass.pygrass.gis import Mapset
m = Mapset()
for r in m.glist('rast'):
if r == "dem":
# don't save the original
continue
raster.out_gdal(r,
format="GTiff",
output="/tmp/{}.tif".format(r),
overwrite=True)