def read_SRTM(fh):
"""
Read the array of (y, x) elevation data from the given named file-handle.
Parameters
==========
fh : file-handle like
A named file-like as passed through to :func:`cartopy.io.fh_getter`.
The filename is used to determine the extent of the resulting array.
Returns
=======
elevation : numpy array
The elevation values from the SRTM file. Data is flipped vertically
such that the higher the y-index, the further north the data. Data
shape is automatically determined by the size of data read from file,
and is either (1201, 1201) for 3 arc-second data or (3601, 3601) for 1
arc-second data.
crs : :class:`cartopy.crs.CRS`
The coordinate reference system of the extents.
extents : 4-tuple (x0, x1, y0, y1)
The boundaries of the returned elevation array.
"""
fh, fname = fh_getter(fh, needs_filename=True)
if fname.endswith('.zip'):
from zipfile import ZipFile
zfh = ZipFile(fh, 'rb')
fh = zfh.open(os.path.basename(fname[:-4]), 'r')
elev = np.fromfile(fh, dtype=np.dtype('>i2'))
if elev.size == 12967201:
elev.shape = (3601, 3601)
elif elev.size == 1442401:
elev.shape = (1201, 1201)
else:
raise ValueError(
'Shape of SRTM data ({}) is unexpected.'.format(elev.size))
fname = os.path.basename(fname)
y_dir, y, x_dir, x = fname[0], int(fname[1:3]), fname[3], int(fname[4:7])
if y_dir == 'S':
y *= -1
if x_dir == 'W':
x *= -1
return elev[::-1, ...], ccrs.PlateCarree(), (x, x + 1, y, y + 1)
def read_SRTM(fh):
"""
Read the array of (y, x) elevation data from the given named file-handle.
Parameters
----------
fh
A named file-like as passed through to :func:`cartopy.io.fh_getter`.
The filename is used to determine the extent of the resulting array.
Returns
-------
elevation
The elevation values from the SRTM file. Data is flipped
vertically such that the higher the y-index, the further north the
data. Data shape is automatically determined by the size of data read
from file, and is either (1201, 1201) for 3 arc-second data or
(3601, 3601) for 1 arc-second data.
crs: :class:`cartopy.crs.CRS`
The coordinate reference system of the extents.
extents: 4-tuple (x0, x1, y0, y1)
The boundaries of the returned elevation array.
"""
fh, fname = fh_getter(fh, needs_filename=True)
if fname.endswith('.zip'):
from zipfile import ZipFile
zfh = ZipFile(fh, 'rb')
fh = zfh.open(os.path.basename(fname[:-4]), 'r')
elev = np.fromfile(fh, dtype=np.dtype('>i2'))
if elev.size == 12967201:
elev.shape = (3601, 3601)
elif elev.size == 1442401:
elev.shape = (1201, 1201)
else:
raise ValueError('Shape of SRTM data ({}) is unexpected.'.format(
elev.size))
fname = os.path.basename(fname)
y_dir, y, x_dir, x = fname[0], int(fname[1:3]), fname[3], int(fname[4:7])
if y_dir == 'S':
y *= -1
if x_dir == 'W':
x *= -1
return elev[::-1, ...], ccrs.PlateCarree(), (x, x + 1, y, y + 1)
def read_SRTM3(fh):
"""
Read the (1201, 1201) array of (y, x) elevation data from the given
named file-handle.
Parameters
==========
fh : file-handle like
A named file-like as passed through to :func:`cartopy.io.fh_getter`.
The filename is used to determine the extent of the resulting array.
Returns
=======
elevation : numpy array
The elevation values from the SRTM file. Data is flipped vertically
such that the higher the the y-index, the further north the data.
crs : :class:`cartopy.crs.CRS`
The coordinate reference system of the extents.
extents : 4-tuple (x0, x1, y0, y1)
The boundaries of the returned elevation array.
"""
fh, fname = fh_getter(fh, needs_filename=True)
if fname.endswith('.zip'):
from zipfile import ZipFile
zfh = ZipFile(fh, 'rb')
fh = zfh.open(os.path.basename(fname[:-4]), 'r')
elev = np.fromfile(fh, dtype=np.dtype('>i2'))
elev.shape = (1201, 1201)
fname = os.path.basename(fname)
y_dir, y, x_dir, x = fname[0], int(fname[1:3]), fname[3], int(fname[4:7])
if y_dir == 'S':
y *= -1
if x_dir == 'W':
x *= -1
return elev[::-1, ...], ccrs.PlateCarree(), (x, x + 1, y, y + 1)
def read_SRTM3(fh):
fh, fname = fh_getter(fh, needs_filename=True)
if fname.endswith('.zip'):
from zipfile import ZipFile
zfh = ZipFile(fh, 'rb')
fh = zfh.open(os.path.basename(fname[:-4]), 'r')
elev = np.fromfile(fh, dtype=np.dtype('>i2'))
elev.shape = (1201, 1201)
fname = os.path.basename(fname)
y_dir, y, x_dir, x = fname[0], int(fname[1:3]), fname[3], int(fname[4:7])
if y_dir == 'S':
y *= -1
if x_dir == 'W':
x *= -1
# xxx extent may need to be wider by half a pixel
return elev[::-1, ...], ccrs.PlateCarree(), [x, x + 1, y, y + 1]
def read_SRTM3(fh):
fh, fname = fh_getter(fh, needs_filename=True)
if fname.endswith('.zip'):
from zipfile import ZipFile
zfh = ZipFile(fh, 'r')
fh = zfh.open(os.path.basename(fname[:-4]), 'r')
elev = numpy.fromfile(fh, dtype=numpy.dtype('>i2'))
elev.shape = (1201, 1201)
fname = os.path.basename(fname)
y_dir, y, x_dir, x = fname[0], int(fname[1:3]), fname[3], int(fname[4:7])
if y_dir == 'S':
y *= -1
if x_dir == 'W':
x *= -1
# xxx extent may need to be wider by half a pixel
return elev[::-1, ...], ccrs.PlateCarree(), [x, x + 1, y, y + 1]