def get_twi(self):
dem_export_fn = '%s/dem_%s.tif' % (os.environ['temporary_folder'],
self._id)
cdem_export_fn = '%s/cdem_%s.tif' % (os.environ['temporary_folder'],
self._id)
direction_export_fn = '%s/direction_%s.tif' % (
os.environ['temporary_folder'], self._id)
accumulation_export_fn = '%s/accumulation_%s.tif' % (
os.environ['temporary_folder'], self._id)
dem = self.read_raster('elevation')
dem.export_as_tif(dem_export_fn)
routing.fill_pits((dem_export_fn, 1), cdem_export_fn)
routing.flow_dir_mfd((cdem_export_fn, 1), direction_export_fn)
routing.flow_accumulation_mfd((direction_export_fn, 1),
accumulation_export_fn)
ds = gdal.Open(accumulation_export_fn)
metadata_dict = {}
metadata_dict['affine_transformation'] = ds.GetGeoTransform()
metadata_dict['nodata'] = -32767
twi = Imagee(np.array(ds.GetRasterBand(1).ReadAsArray()),
metadata_dict)
self.add_raster(twi, 'twi')
os.remove(dem_export_fn)
os.remove(cdem_export_fn)
os.remove(direction_export_fn)
os.remove(accumulation_export_fn)
return twi
def get_twi(im_object):
with TemporaryDirectory() as tempdir:
im_object.export_as_tif('%s/dem.tif' % tempdir)
routing.fill_pits(('%s/dem.tif' % tempdir, 1), '%s/cdem.tif' % tempdir)
routing.flow_dir_mfd(('%s/cdem.tif' % tempdir, 1),
'%s/dir.tif' % tempdir)
routing.flow_accumulation_mfd(('%s/dir.tif' % tempdir, 1),
'%s/twi.tif' % tempdir)
ds = gdal.Open('%s/twi.tif' % tempdir)
metadata_dict = im_object.get_metadata()
twi = Imagee(np.array(ds.GetRasterBand(1).ReadAsArray()),
metadata_dict)
return twi
def flow_accumulation(dem, flow_accum, cleanup=True, dinfinity=False, pitfill=False):
"""
Calculate reach length, slope, drainage area, min and max elevations
and write them as attributes to the network
:param dem: Absolute path to a DEM raster.
:param flow_accum: Absolute path to a flow accumulation raster (cell counts)
:param cleanup: determines whether intermediate rasters are deleted.
:param dinfinity: If true then the dInfinity otherwise d8 algorithm
:param pitfill: If true then DEM is pit filled before flow accumulation
:return: None
"""
log = Logger('Flow Accum')
if os.path.isfile(flow_accum):
log.info('Skipping flow accumulation because output exists at {}'.format(flow_accum))
return None
tempfolder = os.path.join(os.path.dirname(flow_accum), 'temp')
cleanup_temp_folder(tempfolder)
if not os.path.isdir(tempfolder):
os.mkdir(tempfolder)
outputDir = os.path.dirname(flow_accum)
tempPitFill = os.path.join(tempfolder, 'temp_pitfill.tif')
tempFlowDir = os.path.join(tempfolder, 'temp_flowDir.tif')
prepared_dem = dem
if pitfill:
log.info('Filling pits in DEM and writing to {}'.format(tempPitFill))
fill_pits((dem, 1), tempPitFill, working_dir=outputDir)
prepared_dem = tempPitFill
log.info('Calculating flow direction in pit filled raster and writing to: {}'.format(tempFlowDir))
if dinfinity:
flow_dir_mfd((prepared_dem, 1), tempFlowDir)
else:
flow_dir_d8((prepared_dem, 1), tempFlowDir)
log.info('Calculating flow accumulation raster and writing to: {}'.format(flow_accum))
if dinfinity:
flow_accumulation_mfd((tempFlowDir, 1), flow_accum)
else:
flow_accumulation_d8((tempFlowDir, 1), flow_accum)
if cleanup:
cleanup_temp_folder(tempfolder)
log.info('Flow accumulation completed successfully.')
def get_twi(self):
dem_export_fn='/tmp/dem_%s.tif' % self._id
cdem_export_fn='/tmp/cdem_%s.tif' % self._id
direction_export_fn='/tmp/direction_%s.tif' % self._id
accumulation_export_fn='/tmp/accumulation_%s.tif' % self._id
dem=self.read_raster('dem')
dem.export_as_tif(dem_export_fn)
routing.fill_pits((dem_export_fn,1),cdem_export_fn)
routing.flow_dir_mfd((cdem_export_fn,1),direction_export_fn)
routing.flow_accumulation_mfd((direction_export_fn,1),accumulation_export_fn)
ds = gdal.Open(accumulation_export_fn)
metadata_dict={}
metadata_dict['affine_transformation']=ds.GetGeoTransform()
twi=Imagee(np.array(ds.GetRasterBand(1).ReadAsArray()),metadata_dict)
self.add_raster(twi,'twi')
return twi
def drain_area(dem, drain_area_out):
"""
Creates a raster where each pixel represents the contributing
upstream drainage area in km2. DEM should be in a desired projected coordinate system.
PARAMS
:dem: string - path to dem raster file
:drain_area_out: string - path to output drainage area raster file
"""
# sets up intermediate file uris
os.chdir(os.path.dirname(dem))
filled = 'filled.tif'
fd = 'fd.tif'
fa = 'fa.tif'
# geoprocessing functions
rt.fill_pits((dem, 1), filled)
rt.flow_dir_mfd((filled, 1), fd)
rt.flow_accumulation_mfd((fd, 1), fa)
# convert flow accumulation to drainage area
flow_acc = rasterio.open(fa)
resolution = flow_acc.res[0]
flow_acc_array = flow_acc.read(1)
dr_area_array = (flow_acc_array * resolution**2)/1000000.0
# write output file
profile = flow_acc.profile
with rasterio.open(drain_area_out, 'w', **profile) as dst:
dst.write(dr_area_array, 1)
# delete intermediate files
# os.remove(filled)
# os.remove(fd)
# os.remove(fa)
return