Source code for pyart.core.radar_spectra

"""
pyart.core.radar
================

A general central radial scanning (or dwelling) spectra instrument class.

.. autosummary::
    :toctree: generated/
    :template: dev_template.rst

    RadarSpectra


"""
from __future__ import print_function

import sys

import numpy as np

from .radar import Radar


[docs]class RadarSpectra(Radar): """ A class for storing antenna coordinate radar spectra data. Based on the radar object class The structure of the Radar class is based on the CF/Radial Data file format. Global attributes and variables (section 4.1 and 4.3) are represented as a dictionary in the metadata attribute. Other required and optional variables are represented as dictionaries in a attribute with the same name as the variable in the CF/Radial standard. When a optional attribute not present the attribute has a value of None. The data for a given variable is stored in the dictionary under the 'data' key. Moment field data is stored as a dictionary of dictionaries in the fields attribute. Sub-convention variables are stored as a dictionary of dictionaries under the meta_group attribute. Refer to the attribute section for information on the parameters. Attributes ---------- time : dict Time at the center of each ray. range : dict Range to the center of each gate (bin). npulses : dict number of pulses for each ray Doppler_velocity : dict or None The Doppler velocity of each Doppler bin. The data has dimensions nrays x npulses_max Doppler_frequency : dict or None The Doppler frequency of each Doppler bin. The data has dimensions nrays x npulses_max fields : dict of dicts Moment fields. The data has dimensions nrays x ngates x npulses_max metadata : dict Metadata describing the instrument and data. scan_type : str Type of scan, one of 'ppi', 'rhi', 'sector' or 'other'. If the scan volume contains multiple sweep modes this should be 'other'. latitude : dict Latitude of the instrument. longitude : dict Longitude of the instrument. altitude : dict Altitude of the instrument, above sea level. altitude_agl : dict or None Altitude of the instrument above ground level. If not provided this attribute is set to None, indicating this parameter not available. sweep_number : dict The number of the sweep in the volume scan, 0-based. sweep_mode : dict Sweep mode for each mode in the volume scan. fixed_angle : dict Target angle for thr sweep. Azimuth angle in RHI modes, elevation angle in all other modes. sweep_start_ray_index : dict Index of the first ray in each sweep relative to the start of the volume, 0-based. sweep_end_ray_index : dict Index of the last ray in each sweep relative to the start of the volume, 0-based. rays_per_sweep : LazyLoadDict Number of rays in each sweep. The data key of this attribute is create upon first access from the data in the sweep_start_ray_index and sweep_end_ray_index attributes. If the sweep locations needs to be modified, do this prior to accessing this attribute or use :py:func:`init_rays_per_sweep` to reset the attribute. target_scan_rate : dict or None Intended scan rate for each sweep. If not provided this attribute is set to None, indicating this parameter is not available. rays_are_indexed : dict or None Indication of whether ray angles are indexed to a regular grid in each sweep. If not provided this attribute is set to None, indicating ray angle spacing is not determined. ray_angle_res : dict or None If rays_are_indexed is not None, this provides the angular resolution of the grid. If not provided or available this attribute is set to None. azimuth : dict Azimuth of antenna, relative to true North. Azimuth angles are recommended to be expressed in the range of [0, 360], but other representations are not forbidden. elevation : dict Elevation of antenna, relative to the horizontal plane. Elevation angles are recommended to be expressed in the range of [-180, 180], but other representations are not forbidden. gate_x, gate_y, gate_z : LazyLoadDict Location of each gate in a Cartesian coordinate system assuming a standard atmosphere with a 4/3 Earth's radius model. The data keys of these attributes are create upon first access from the data in the range, azimuth and elevation attributes. If these attributes are changed use :py:func:`init_gate_x_y_z` to reset. gate_longitude, gate_latitude : LazyLoadDict Geographic location of each gate. The projection parameter(s) defined in the `projection` attribute are used to perform an inverse map projection from the Cartesian gate locations relative to the radar location to longitudes and latitudes. If these attributes are changed use :py:func:`init_gate_longitude_latitude` to reset the attributes. projection : dic or str Projection parameters defining the map projection used to transform from Cartesian to geographic coordinates. The default dictionary sets the 'proj' key to 'pyart_aeqd' indicating that the native Py-ART azimuthal equidistant projection is used. This can be modified to specify a valid pyproj.Proj projparams dictionary or string. The special key '_include_lon_0_lat_0' is removed when interpreting this dictionary. If this key is present and set to True, which is required when proj='pyart_aeqd', then the radar longitude and latitude will be added to the dictionary as 'lon_0' and 'lat_0'. gate_altitude : LazyLoadDict The altitude of each radar gate as calculated from the altitude of the radar and the Cartesian z location of each gate. If this attribute is changed use :py:func:`init_gate_altitude` to reset the attribute. scan_rate : dict or None Actual antenna scan rate. If not provided this attribute is set to None, indicating this parameter is not available. antenna_transition : dict or None Flag indicating if the antenna is in transition, 1 = yes, 0 = no. If not provided this attribute is set to None, indicating this parameter is not available. rotation : dict or None The rotation angle of the antenna. The angle about the aircraft longitudinal axis for a vertically scanning radar. tilt : dict or None The tilt angle with respect to the plane orthogonal (Z-axis) to aircraft longitudinal axis. roll : dict or None The roll angle of platform, for aircraft right wing down is positive. drift : dict or None Drift angle of antenna, the angle between heading and track. heading : dict or None Heading (compass) angle, clockwise from north. pitch : dict or None Pitch angle of antenna, for aircraft nose up is positive. georefs_applied : dict or None Indicates whether the variables have had georeference calculation applied. Leading to Earth-centric azimuth and elevation angles. instrument_parameters : dict of dicts or None Instrument parameters, if not provided this attribute is set to None, indicating these parameters are not avaiable. This dictionary also includes variables in the radar_parameters CF/Radial subconvention. radar_calibration : dict of dicts or None Instrument calibration parameters. If not provided this attribute is set to None, indicating these parameters are not available ngates : int Number of gates (bins) in a ray. nrays : int Number of rays in the volume. npulses_max : int Maximum number of pulses per ray in the volume. nsweeps : int Number of sweep in the volume. """
[docs] def __init__(self, time, _range, fields, metadata, scan_type, latitude, longitude, altitude, sweep_number, sweep_mode, fixed_angle, sweep_start_ray_index, sweep_end_ray_index, azimuth, elevation, npulses, Doppler_velocity=None, Doppler_frequency=None, altitude_agl=None, target_scan_rate=None, rays_are_indexed=None, ray_angle_res=None, scan_rate=None, antenna_transition=None, instrument_parameters=None, radar_calibration=None, rotation=None, tilt=None, roll=None, drift=None, heading=None, pitch=None, georefs_applied=None, ): if 'calendar' not in time: time['calendar'] = 'gregorian' self.time = time self.range = _range self.fields = fields self.metadata = metadata self.scan_type = scan_type self.latitude = latitude self.longitude = longitude self.altitude = altitude self.altitude_agl = altitude_agl # optional self.sweep_number = sweep_number self.sweep_mode = sweep_mode self.fixed_angle = fixed_angle self.sweep_start_ray_index = sweep_start_ray_index self.sweep_end_ray_index = sweep_end_ray_index self.target_scan_rate = target_scan_rate # optional self.rays_are_indexed = rays_are_indexed # optional self.ray_angle_res = ray_angle_res # optional self.azimuth = azimuth self.elevation = elevation self.Doppler_velocity = Doppler_velocity # optional self.Doppler_frequency = Doppler_frequency # optional self.scan_rate = scan_rate # optional self.antenna_transition = antenna_transition # optional self.rotation = rotation # optional self.tilt = tilt # optional self.roll = roll # optional self.drift = drift # optional self.heading = heading # optional self.pitch = pitch # optional self.georefs_applied = georefs_applied # optional self.instrument_parameters = instrument_parameters # optional self.radar_calibration = radar_calibration # optional self.ngates = len(_range['data']) self.nrays = len(time['data']) self.npulses = npulses self.npulses_max = np.max(npulses['data']) self.nsweeps = len(sweep_number['data']) self.projection = {'proj': 'pyart_aeqd', '_include_lon_0_lat_0': True} # initalize attributes with lazy load dictionaries self.init_rays_per_sweep() self.init_gate_x_y_z() self.init_gate_longitude_latitude() self.init_gate_altitude()
[docs] def add_field(self, field_name, dic, replace_existing=False): """ Add a field to the object. Parameters ---------- field_name : str Name of the field to add to the dictionary of fields. dic : dict Dictionary contain field data and metadata. replace_existing : bool True to replace the existing field with key field_name if it exists, loosing any existing data. False will raise a ValueError when the field already exists. """ # check that the field dictionary to add is valid if field_name in self.fields and replace_existing is False: err = 'A field with name: %s already exists' % (field_name) raise ValueError(err) if 'data' not in dic: raise KeyError("dic must contain a 'data' key") if dic['data'].shape != (self.nrays, self.ngates, self.npulses_max): t = ( self.nrays, self.ngates, self.npulses_max, dic['data'].shape[0], dic['data'].shape[1], dic['data'].shape[2]) err = ( "'data' has invalid shape, " + "should be (%i, %i, %i) but is (%i, %i, %i)" % t) raise ValueError(err) # add the field self.fields[field_name] = dic
[docs] def add_field_like(self, existing_field_name, field_name, data, replace_existing=False): """ Add a field to the object with metadata from a existing field. Note that the data parameter is not copied by this method. If data refers to a 'data' array from an existing field dictionary, a copy should be made within or prior to using this method. If this is not done the 'data' key in both field dictionaries will point to the same NumPy array and modification of one will change the second. To copy NumPy arrays use the copy() method. See the Examples section for how to create a copy of the 'reflectivity' field as a field named 'reflectivity_copy'. Parameters ---------- existing_field_name : str Name of an existing field to take metadata from when adding the new field to the object. field_name : str Name of the field to add to the dictionary of fields. data : array Field data. A copy of this data is not made, see the note above. replace_existing : bool True to replace the existing field with key field_name if it exists, loosing any existing data. False will raise a ValueError when the field already exists. Examples -------- >>> radar.add_field_like('reflectivity', 'reflectivity_copy', ... radar.fields['reflectivity']['data'].copy()) """ if existing_field_name not in self.fields: err = 'field %s does not exist in object' % (existing_field_name) raise ValueError(err) dic = {} for k, v in self.fields[existing_field_name].items(): if k != 'data': dic[k] = v dic['data'] = data return self.add_field(field_name, dic, replace_existing=replace_existing)
[docs] def extract_sweeps(self, sweeps): """ Create a new radar contains only the data from select sweeps. Parameters ---------- sweeps : array_like Sweeps (0-based) to include in new Radar object. Returns ------- radar : Radar Radar object which contains a copy of data from the selected sweeps. """ # parse and verify parameters sweeps = np.array(sweeps, dtype='int32') if np.any(sweeps > (self.nsweeps - 1)): raise ValueError('invalid sweeps indices in sweeps parameter. ' + 'sweeps: '+' '.join(str(sweeps)) + ' nsweeps: '+str(self.nsweeps)) if np.any(sweeps < 0): raise ValueError('only positive sweeps can be extracted') def mkdic(dic, select): """ Make a dictionary, selecting out select from data key """ if dic is None: return None d = dic.copy() if 'data' in d and select is not None: d['data'] = d['data'][select].copy() return d # create array of rays which select the sweeps selected and # the number of rays per sweep. ray_count = (self.sweep_end_ray_index['data'] - self.sweep_start_ray_index['data'] + 1)[sweeps] ssri = self.sweep_start_ray_index['data'][sweeps] rays = np.concatenate( [range(s, s+e) for s, e in zip(ssri, ray_count)]).astype('int32') # radar location attribute dictionary selector if len(self.altitude['data']) == 1: loc_select = None else: loc_select = sweeps # create new dictionaries time = mkdic(self.time, rays) _range = mkdic(self.range, None) fields = {} for field_name, dic in self.fields.items(): fields[field_name] = mkdic(dic, rays) metadata = mkdic(self.metadata, None) scan_type = str(self.scan_type) latitude = mkdic(self.latitude, loc_select) longitude = mkdic(self.longitude, loc_select) altitude = mkdic(self.altitude, loc_select) altitude_agl = mkdic(self.altitude_agl, loc_select) sweep_number = mkdic(self.sweep_number, sweeps) sweep_mode = mkdic(self.sweep_mode, sweeps) fixed_angle = mkdic(self.fixed_angle, sweeps) sweep_start_ray_index = mkdic(self.sweep_start_ray_index, None) sweep_start_ray_index['data'] = np.cumsum(np.append( [0], ray_count[:-1])) sweep_end_ray_index = mkdic(self.sweep_end_ray_index, None) sweep_end_ray_index['data'] = np.cumsum(ray_count) - 1 target_scan_rate = mkdic(self.target_scan_rate, sweeps) azimuth = mkdic(self.azimuth, rays) elevation = mkdic(self.elevation, rays) Doppler_velocity = mkdic(self.Doppler_velocity, rays) Doppler_frequency = mkdic(self.Doppler_frequency, rays) scan_rate = mkdic(self.scan_rate, rays) antenna_transition = mkdic(self.antenna_transition, rays) # instrument_parameters # Filter the instrument_parameter dictionary based size of leading # dimension, this might not always be correct. if self.instrument_parameters is None: instrument_parameters = None else: instrument_parameters = {} for key, dic in self.instrument_parameters.items(): if dic['data'].ndim != 0: dim0_size = dic['data'].shape[0] else: dim0_size = -1 if dim0_size == self.nsweeps: fdic = mkdic(dic, sweeps) elif dim0_size == self.nrays: fdic = mkdic(dic, rays) else: # keep everything fdic = mkdic(dic, None) instrument_parameters[key] = fdic # radar_calibration # copy all field in radar_calibration as is except for # r_calib_index which we filter based upon time. This might # leave some indices in the "r_calib" dimension not referenced in # the r_calib_index array. if self.radar_calibration is None: radar_calibration = None else: radar_calibration = {} for key, dic in self.radar_calibration.items(): if key == 'r_calib_index': radar_calibration[key] = mkdic(dic, rays) else: radar_calibration[key] = mkdic(dic, None) return RadarSpectra( time, _range, fields, metadata, scan_type, latitude, longitude, altitude, sweep_number, sweep_mode, fixed_angle, sweep_start_ray_index, sweep_end_ray_index, azimuth, elevation, self.npulses, Doppler_velocity=Doppler_velocity, Doppler_frequency=Doppler_frequency, altitude_agl=altitude_agl, target_scan_rate=target_scan_rate, scan_rate=scan_rate, antenna_transition=antenna_transition, instrument_parameters=instrument_parameters, radar_calibration=radar_calibration)
[docs] def info(self, level='standard', out=sys.stdout): """ Print information on radar. Parameters ---------- level : {'compact', 'standard', 'full', 'c', 's', 'f'} Level of information on radar object to print, compact is minimal information, standard more and full everything. out : file-like Stream to direct output to, default is to print information to standard out (the screen). """ if level == 'c': level = 'compact' elif level == 's': level = 'standard' elif level == 'f': level = 'full' if level not in ['standard', 'compact', 'full']: raise ValueError('invalid level parameter') self._dic_info('altitude', level, out) self._dic_info('altitude_agl', level, out) self._dic_info('antenna_transition', level, out) self._dic_info('azimuth', level, out) self._dic_info('elevation', level, out) print('fields:', file=out) for field_name, field_dic in self.fields.items(): self._dic_info(field_name, level, out, field_dic, 1) self._dic_info('fixed_angle', level, out) if self.instrument_parameters is None: print('instrument_parameters: None', file=out) else: print('instrument_parameters:', file=out) for name, dic in self.instrument_parameters.items(): self._dic_info(name, level, out, dic, 1) self._dic_info('latitude', level, out) self._dic_info('longitude', level, out) print('nsweeps:', self.nsweeps, file=out) print('ngates:', self.ngates, file=out) print('nrays:', self.nrays, file=out) print('npulses_max:', self.npulses_max, file=out) if self.radar_calibration is None: print('radar_calibration: None', file=out) else: print('radar_calibration:', file=out) for name, dic in self.radar_calibration.items(): self._dic_info(name, level, out, dic, 1) self._dic_info('range', level, out) self._dic_info('scan_rate', level, out) print('scan_type:', self.scan_type, file=out) self._dic_info('sweep_end_ray_index', level, out) self._dic_info('sweep_mode', level, out) self._dic_info('sweep_number', level, out) self._dic_info('sweep_start_ray_index', level, out) self._dic_info('target_scan_rate', level, out) self._dic_info('time', level, out) # Airborne radar parameters if self.rotation is not None: self._dic_info('rotation', level, out) if self.tilt is not None: self._dic_info('tilt', level, out) if self.roll is not None: self._dic_info('roll', level, out) if self.drift is not None: self._dic_info('drift', level, out) if self.heading is not None: self._dic_info('heading', level, out) if self.pitch is not None: self._dic_info('pitch', level, out) if self.georefs_applied is not None: self._dic_info('georefs_applied', level, out) # always print out all metadata last self._dic_info('metadata', 'full', out)