Source code for gammapy.data.filters

# Licensed under a 3-clause BSD style license - see LICENSE.rst
from __future__ import absolute_import, division, print_function, unicode_literals
import logging

__all__ = ["ObservationFilter"]

log = logging.getLogger(__name__)


[docs]class ObservationFilter(object): """Holds and applies filters to observation data. Parameters ---------- time_filter : `astropy.time.Time` Start and stop time of the selected time interval. For now we only support a single time interval. event_filters : list of dict An event filter dictionary needs two keys: - **type** : str, one of the keys in `~gammapy.data.ObservationFilter.EVENT_FILTER_TYPES` - **opts** : dict, it is passed on to the method of the `~gammapy.data.EventListBase` class that corresponds to the filter type (see `~gammapy.data.ObservationFilter.EVENT_FILTER_TYPES`) The filtered event list will be an intersection of all filters. A union of filters is not supported yet. Examples -------- >>> from gammapy.data import ObservationFilter, DataStore, DataStoreObservation >>> from astropy.time import Time >>> from astropy.coordinates import Angle >>> >>> time_filter = Time(['2021-03-27T20:10:00', '2021-03-27T20:20:00']) >>> phase_filter = {'type': 'custom', 'opts': dict(parameter='PHASE', limits=(0.2, 0.8))} >>> >>> my_obs_filter = ObservationFilter(time_filter=time_filter, event_filters=[phase_filter]) >>> >>> ds = DataStore.from_dir("$GAMMAPY_DATA/cta-1dc/index/gps") >>> my_obs = DataStoreObservation(obs_id=111630, data_store=ds, obs_filter=my_obs_filter) """ EVENT_FILTER_TYPES = dict( box_region="select_sky_box", circular_region="select_circular_region", custom="select_custom", ) def __init__(self, time_filter=None, event_filters=None): self.time_filter = time_filter self.event_filters = event_filters or []
[docs] def filter_events(self, events): """Applies the filters to an event list Parameters ---------- events : `~gammapy.data.EventListBase` Event list to which the filters will be applied Returns ------- filtered_events : `~gammapy.data.EventListBase` The filtered event list """ filtered_events = self._filter_by_time(events) for f in self.event_filters: method_str = self.EVENT_FILTER_TYPES[f["type"]] filtered_events = getattr(filtered_events, method_str)(**f["opts"]) return filtered_events
[docs] def filter_gti(self, gti): """Applies the filters to a GTI table Parameters ---------- gti : `~gammapy.data.GTI` GTI table to which the filters will be applied Returns ------- filtered_gti : `~gammapy.data.GTI` The filtered GTI table """ filtered_gti = self._filter_by_time(gti) return filtered_gti
def _filter_by_time(self, data): """Returns a new time filtered data object. Calls the `select_time` method of the data object. """ if self.time_filter: return data.select_time(self.time_filter) else: return data