Composition#

Combine data from different radar locations on one common set of locations

extract_circle

Extract the indices of coords which fall within a circle defined by center and radius.

togrid

Interpolate data from a radar location to the composite grid or set of locations

compose_ko

Composes grids according to quality information using quality information as a knockout criterion.

compose_weighted

Composes grids according to quality information using a weighted averaging approach.

CompMethods

wradlib xarray SubAccessor methods for Ipol Methods.

wradlib.comp.extract_circle(center, radius, coords)[source]#

Extract the indices of coords which fall within a circle defined by center and radius.

Parameters
Returns

output (numpy.ndarray) – 1-darray of integers, index array referring to the coords array

wradlib.comp.togrid(src, trg, radius, center, data, interpol, *args, **kwargs)[source]#
wradlib.comp.togrid(obj: DataArray, trg, *args, **kwargs)

Interpolate data from a radar location to the composite grid or set of locations

Parameters
  • src (numpy.ndarray) – array of float of shape (numpoints, ndim), cartesian x / y coordinates of the radar bins

  • trg (numpy.ndarray) – array of float of shape (numpoints, ndim), cartesian x / y coordinates of the composite

  • radius (float) – the radius of the radar circle (same units as src and trg)

  • center (numpy.ndarray) – array of float, the location coordinates of the radar

  • data (numpy.ndarray) – array of float, the data that should be transferred to composite

  • interpol (IpolBase) – an interpolation class name from wradlib.ipol e.g. Nearest or Idw

Other Parameters

*args (dict) – arguments of Interpolator (see class documentation)

Keyword Arguments

**kwargs (dict) – keyword arguments of Interpolator (see class documentation)

Returns

output (numpy.ndarray) – array of float, data of the radar circle which is interpolated on the composite grid

Note

Keyword arguments to be used while calling the interpolator can be issued as call_kwargs, e.g. togrid(…, call_kwargs=dict(maxdist=10))

Examples

See Gridding.

wradlib.comp.compose_ko(radargrids, qualitygrids)[source]#

Composes grids according to quality information using quality information as a knockout criterion.

The value of the composed pixel is taken from the radargrid whose quality grid has the highest value.

Parameters
  • radargrids (list) – radar data to be composited. Each item in the list corresponds to the data of one radar location. All items must have the same shape.

  • qualitygrids (list) – quality data to decide upon which radar site will contribute its pixel to the composite. Then length of this list must be the same as that of radargrids. All items must have the same shape and be aligned with the items in radargrids.

Returns

composite (numpy.ndarray)

wradlib.comp.compose_weighted(radargrids, qualitygrids)[source]#
wradlib.comp.compose_weighted(radargrids: DataArray, qualitygrids)

Composes grids according to quality information using a weighted averaging approach.

The value of the composed pixel is the weighted average of all radar pixels with the quality values being the weights.

Parameters
  • radargrids (list) – list of arrays

  • qualitygrids (list) – list of arrays

Returns

composite (numpy.ndarray)

Examples

See Recipe #1: Clutter and attenuation correction plus composition for two DWD radars.

See also

compose_ko

class wradlib.comp.CompMethods(obj)[source]#

Bases: XarrayMethods

wradlib xarray SubAccessor methods for Ipol Methods.

togrid(trg, radius, center, data, interpol, *args, **kwargs)[source]#

Interpolate data from a radar location to the composite grid or set of locations

Parameters
  • src (numpy.ndarray) – array of float of shape (numpoints, ndim), cartesian x / y coordinates of the radar bins

  • trg (numpy.ndarray) – array of float of shape (numpoints, ndim), cartesian x / y coordinates of the composite

  • radius (float) – the radius of the radar circle (same units as src and trg)

  • center (numpy.ndarray) – array of float, the location coordinates of the radar

  • data (numpy.ndarray) – array of float, the data that should be transferred to composite

  • interpol (IpolBase) – an interpolation class name from wradlib.ipol e.g. Nearest or Idw

Other Parameters

*args (dict) – arguments of Interpolator (see class documentation)

Keyword Arguments

**kwargs (dict) – keyword arguments of Interpolator (see class documentation)

Returns

output (numpy.ndarray) – array of float, data of the radar circle which is interpolated on the composite grid

Note

Keyword arguments to be used while calling the interpolator can be issued as call_kwargs, e.g. togrid(…, call_kwargs=dict(maxdist=10))

Examples

See Gridding.

compose_weighted(qualitygrids)[source]#

Composes grids according to quality information using a weighted averaging approach.

The value of the composed pixel is the weighted average of all radar pixels with the quality values being the weights.

Parameters
  • radargrids (list) – list of arrays

  • qualitygrids (list) – list of arrays

Returns

composite (numpy.ndarray)

Examples

See Recipe #1: Clutter and attenuation correction plus composition for two DWD radars.

See also

compose_ko