def mk_sample_xr_dataset(crs="EPSG:3578",
shape=(33, 74),
resolution=None,
xy=(0, 0),
time='2020-02-13T11:12:13.1234567Z',
name='band',
dtype='int16',
nodata=-999,
units='1'):
""" Note that resolution is in Y,X order to match that of GeoBox.
shape (height, width)
resolution (y: float, x: float) - in YX, to match GeoBox/shape notation
xy (x: float, y: float) -- location of the top-left corner of the top-left pixel in CRS units
"""
if isinstance(crs, str):
crs = CRS(crs)
if resolution is None:
resolution = (-10, 10) if crs is None or crs.projected else (-0.01, 0.01)
t_coords = {}
if time is not None:
t_coords['time'] = mk_time_coord([time])
transform = Affine.translation(*xy)*Affine.scale(*resolution[::-1])
h, w = shape
geobox = GeoBox(w, h, transform, crs)
return Datacube.create_storage(t_coords, geobox, [Measurement(name=name, dtype=dtype, nodata=nodata, units=units)])
def odc_style_xr_dataset():
"""An xarray.Dataset with ODC style coordinates and CRS, and no time dimension.
Contains an EPSG:4326, single variable 'B10' of 100x100 int16 pixels."""
affine = Affine.scale(0.1, 0.1) * Affine.translation(20, 30)
geobox = geometry.GeoBox(100, 100, affine, geometry.CRS(GEO_PROJ))
return Datacube.create_storage({}, geobox, [Measurement(name='B10', dtype='int16', nodata=0, units='1')])
def fractional_cover(nbar_tile,
measurements=None,
regression_coefficients=None):
"""
Given a tile of spectral observations compute the fractional components.
The data should be a 2D array
:param xarray.Dataset nbar_tile:
A dataset with the following data variables (0-10000):
* green
* red
* nir
* swir1
* swir2
:param list(dict) measurements:
A list of measurement item dicts, each containing:
* name - name of output data_var
* src_var - (optional) if `name` is not one of `['PV', 'NPV', 'BS', 'UE']`, use one of them here
* dtype - dtype to use, eg `'int8'`
* nodata - value to fill in for no data, eg `-1`
* units' - eg `'percent'`
:param dict regression_coefficients:
A dictionary with six pairs of coefficients to apply to the green, red, nir, swir1 and swir2 values
(blue is not used)
:return:
An xarray.Dataset containing:
* Green vegetation (PV)
* Non-green vegetation (NPV)
* Bare soil (BS)
* Unmixing error (UE)
:rtype:
xarray.Dataset
"""
if measurements is None:
measurements = DEFAULT_MEASUREMENTS
# Ensure the bands are all there and in the right order
nbar_tile = nbar_tile[['green', 'red', 'nir', 'swir1', 'swir2']]
# Set nodata to 0
no_data = 0
is_valid_array = valid_data_mask(nbar_tile).to_array(dim='band').all(
dim='band')
nbar = nbar_tile.to_array(dim='band')
nbar.data[:, ~is_valid_array.data] = no_data
output_data = compute_fractions(nbar.data, regression_coefficients)
def data_func(measurement):
band_names = ['PV', 'NPV', 'BS', 'UE']
src_var = measurement.get('src_var', None) or measurement.get('name')
i = band_names.index(src_var)
# Set nodata value into output array
band_nodata = numpy.dtype(measurement['dtype']).type(
measurement['nodata'])
compute_error = (output_data[i, :, :] == -1)
output_data[i, compute_error] = band_nodata
output_data[i, ~is_valid_array.data] = band_nodata
return output_data[i, :, :]
dataset = Datacube.create_storage({}, nbar_tile.geobox, measurements,
data_func)
return dataset
def fractional_cover(
nbar_tile: xarray.Dataset,
measurements: Sequence[Measurement] = None,
regression_coefficients: Mapping[str,
Sequence[int]] = None) -> xarray.Dataset:
"""
Given a tile of spectral observations compute the fractional components.
The data should be a 2D array
:param nbar_tile:
A dataset with the following data variables (0-10000):
* green
* red
* nir
* swir1
* swir2
:param measurements:
A list of Measurements, each containing:
* name - name of output data_var
* src_var - (optional) if `name` is not one of `['PV', 'NPV', 'BS', 'UE']`, use one of them here
* dtype - dtype to use, eg `'int8'`
* nodata - value to fill in for no data, eg `-1`
* units' - eg `'percent'`
:param regression_coefficients:
A dictionary with six pairs of coefficients to apply to the green, red, nir, swir1 and swir2 values
(blue is not used)
:return:
An xarray.Dataset containing:
* Green vegetation (PV)
* Non-green vegetation (NPV)
* Bare soil (BS)
* Unmixing error (UE)
:rtype:
xarray.Dataset
"""
if measurements is None:
measurements = DEFAULT_MEASUREMENTS
# Ensure the bands are all there and in the right order
nbar_tile = nbar_tile[['green', 'red', 'nir', 'swir1', 'swir2']]
# Set nodata to 0
no_data = 0
is_valid_array = valid_data_mask(nbar_tile).to_array(dim='band').all(
dim='band')
nbar = nbar_tile.to_array(dim='band')
nbar = nbar.where(is_valid_array, no_data)
output_data = compute_fractions(nbar.data, regression_coefficients)
error_val = -1
where = numpy.where if not isinstance(
output_data, dask_array_type) else dask.array.where
def data_func(measurement):
band_names = ['PV', 'NPV', 'BS', 'UE']
src_var = measurement.get('src_var', None) or measurement.get('name')
i = band_names.index(src_var.upper())
unmasked_var = output_data[i]
# Set nodata value into output array
band_nodata = numpy.dtype(measurement['dtype']).type(
measurement['nodata'])
no_error = (unmasked_var != error_val)
return where(is_valid_array.data & no_error, unmasked_var, band_nodata)
dataset = Datacube.create_storage({}, nbar_tile.geobox, measurements,
data_func)
return dataset