"comment" : "Used as vel_misfit_weight in inversion for tauc",
"units" : "",
"mapping" : "mapping",
"_FillValue" : 0})
var = np.fromfile(vx_filename, dtype=">f4", count=-1)
mask = var/var
mask[var == -2e9] = 0.
nc.write_2d_field("vel_surface_mask", mask)
mapping = nc.createVariable("mapping", 'c')
mapping.grid_mapping_name = "polar_stereographic"
mapping.standard_parallel = 70.0
mapping.latitude_of_projection_origin = 90.0
mapping.straight_vertical_longitude_from_pole = -45.0
mapping.ellipsoid = "WGS84"
nc.Conventions = "CF-1.4"
nc.projection = "+proj=stere +ellps=WGS84 +datum=WGS84 +lon_0=-45 +lat_0=90 +lat_ts=70 +units=m"
nc.reference = "Joughin, I., B. Smith, I. Howat, and T. Scambos. 2010. MEaSUREs Greenland Ice Velocity Map from InSAR Data. Boulder, Colorado, USA: National Snow and Ice Data Center. Digital media."
nc.title = "MEaSUREs Greenland Ice Velocity Map from InSAR Data"
from time import asctime
import sys
separator = ' '
historystr = "%s: %s\n" % (asctime(), separator.join(sys.argv))
nc.history = historystr
nc.close()
def vel_mosaic2netcdf(filename_base, output_filename):
files = []
for (short_name, long_name) in [("vx", "ice surface velocity in the X direction"),
("vy", "ice surface velocity in the Y direction"),
("ex",
"error estimates for the X-component of the ice surface velocity"),
("ey",
"error estimates for the Y-component of the ice surface velocity"),
]:
try:
os.stat(filename_base + "." + short_name)
entry = ("%s.%s" %(filename_base,short_name), short_name, long_name)
files.append(entry)
except:
print "Missing %s.%s. If this file ends with ex or ey the script will work just fine" %(filename_base, short_name)
grid = np.loadtxt(filename_base + ".vx.geodat", skiprows=1, comments="&")
shape = (int(grid[0,1]), int(grid[0,0]))
x0 = grid[2,0] * 1e3
y0 = grid[2,1] * 1e3
dx = grid[1,0]
dy = grid[1,1]
x1 = x0 + (shape[1] - 1) * dx
y1 = y0 + (shape[0] - 1) * dx
x = np.linspace(x0, x1, shape[1])
y = np.linspace(y0, y1, shape[0])
nc = NC("%s.nc" % output_filename, 'w')
nc.create_dimensions(x, y)
for (filename, short_name, long_name) in files:
nc.define_2d_field(short_name, time_dependent = False, nc_type='f4',
attrs = {"long_name" : long_name,
"comment" : "Downloaded from %s" % (ftp_url + filename),
"units" : "m / year",
"mapping" : "mapping",
"_FillValue" : -2e+9})
var = np.fromfile(filename, dtype=">f4", count=-1)
nc.write_2d_field(short_name, var)
# Add a mask that shows where observations are present
if options.add_mask == True:
nc.define_2d_field("vel_surface_mask", time_dependent = False, nc_type='i',
attrs = {"long_name" : "Mask observations; 1 where surface vel. available",
"comment" : "Used as vel_misfit_weight in inversion for tauc",
"units" : "",
"mapping" : "mapping",
"_FillValue" : 0})
var = np.fromfile(filename_base + ".vx", dtype=">f4", count=-1)
mask = var/var
mask[var == -2e9] = 0.
nc.write_2d_field("vel_surface_mask", mask)
mapping = nc.createVariable("mapping", 'c')
mapping.grid_mapping_name = "polar_stereographic"
mapping.standard_parallel = 70.0
mapping.latitude_of_projection_origin = 90.0
mapping.straight_vertical_longitude_from_pole = -45.0
mapping.ellipsoid = "WGS84"
nc.Conventions = "CF-1.4"
nc.projection = "+proj=stere +ellps=WGS84 +datum=WGS84 +lon_0=-45 +lat_0=90 +lat_ts=70 +units=m"
nc.reference = "Joughin, I., B. Smith, I. Howat, and T. Scambos. 2010. MEaSUREs Greenland Ice Velocity Map from InSAR Data. Boulder, Colorado, USA: National Snow and Ice Data Center. Digital media."
nc.title = "MEaSUREs Greenland Ice Velocity Map from InSAR Data"
from time import asctime
import sys
separator = ' '
historystr = "%s: %s\n" % (asctime(), separator.join(sys.argv))
nc.history = historystr
nc.close()
def grid2netcdf(filename_base, output_filename):
print "Reading txt files with data ..."
x, y, topg, fill_value = readComposite("%sbottom.txt" % filename_base)
x, y, thk, fill_value = readComposite("%sthickness.txt" % filename_base)
x, y, usurf, fill_value = readComposite("%ssurface.txt" % filename_base)
nc = NC("%s.nc" % output_filename, "w")
nc.create_dimensions(x, y)
names = []
for (short_name, long_name) in [
("topg", "bedrock surface elevation"),
("thk", "land ice thickness"),
("usurf", "ice upper surface elevation"),
]:
entry = (short_name, long_name)
names.append(entry)
var = [topg, thk, usurf]
for i, (short_name, long_name) in enumerate(names):
nc.define_2d_field(
short_name,
time_dependent=False,
nc_type="f4",
attrs={
"long_name": long_name,
"comment": "Downloaded from ftp://data.cresis.ku.edu/data/grids/Jakobshavn_2006_2012_Composite.zip",
"units": "m",
"mapping": "mapping",
"_FillValue": fill_value,
},
)
nc.write_2d_field(short_name, var[i])
# Add a mask that shows where observations are present
nc.define_2d_field(
"obs_mask",
time_dependent=False,
nc_type="i",
attrs={
"long_name": "Mask observations; 1 where observations available",
"units": "",
"mapping": "mapping",
"_FillValue": 0,
},
)
mask = np.ones(thk.shape)
mask[thk == fill_value] = 0.0
nc.write_2d_field("obs_mask", mask)
mapping = nc.createVariable("mapping", "c")
mapping.grid_mapping_name = "polar_stereographic"
mapping.standard_parallel = 70.0
mapping.latitude_of_projection_origin = 90.0
mapping.straight_vertical_longitude_from_pole = -45.0
mapping.ellipsoid = "WGS84"
nc.Conventions = "CF-1.4"
nc.projection = "+proj=stere +ellps=WGS84 +datum=WGS84 +lon_0=-45 +lat_0=90 +lat_ts=70 +units=m"
nc.reference = "Gogineni, Prasad. 2012. CReSIS Radar Depth Sounder Data, Lawrence, Kansas, USA. Digital Media. http://data.cresis.ku.edu"
nc.title = "CReSIS Gridded Depth Sounder Data for Jakobshavn, Greenland"
nc.acknowledgement = "We acknowledge the use of data and/or data products from CReSIS generated with support from NSF grant ANT-0424589 and NASA grant NNX10AT68G"
from time import asctime
import sys
separator = " "
historystr = "%s: %s\n" % (asctime(), separator.join(sys.argv))
nc.history = historystr
print "Done writing %s.nc ..." % output_filename
nc.close()
# Run nc2cdo to add lat/lon
print "Adding lat/lon by running nc2cdo.py ..."
os.system("nc2cdo.py %s.nc" % output_filename)
