TimeMapAxis

class gammapy.maps.TimeMapAxis(edges_min, edges_max, reference_time, name='time', interp='lin')

Bases: object

Class representing a time axis.

Provides methods for transforming to/from axis and pixel coordinates. A time axis can represent non-contiguous sequences of non-overlapping time intervals.

Time intervals must be provided in increasing order.

Parameters

edges_minQuantity

Array of edge time values. This the time delta w.r.t. to the reference time.

edges_maxQuantity

Array of edge time values. This the time delta w.r.t. to the reference time.

reference_timeTime

Reference time to use.

namestr

Axis name

interpstr

Interpolation method used to transform between axis and pixel coordinates. For now only ‘lin’ is supported.

Attributes Summary

as_plot_center	Plot center
as_plot_edges	Plot edges
as_plot_labels	Plot labels
as_plot_xerr	Plot x error
bin_width	Return time interval width (Quantity).
bounds	Bounds of the axis (~astropy.units.Quantity)
center	Return Quantity at interval centers.
edges	Return array of bin edges values.
edges_max	Return array of bin edges min values.
edges_min	Return array of bin edges max values.
interp	Interp
is_contiguous	Whether the axis is contiguous
iter_by_edges	Iterate by intervals defined by the edges
name	Return axis name.
nbin	Return number of bins in the axis.
node_type
reference_time	Return reference time used for the axis.
time_bounds	Bounds of the axis (~astropy.units.Quantity)
time_delta	Return axis time bin width (TimeDelta).
time_edges	Time edges
time_format
time_max	Return axis upper edges as Time objects.
time_mid	Return time bin center (Time).
time_min	Return axis lower edges as Time objects.
unit	Axes unit

Methods Summary

assert_name(required_name)	Assert axis name if a specific one is required.
coord_to_idx(coord, **kwargs)	Transform from axis time coordinate to bin index.
coord_to_pix(coord, **kwargs)	Transform from time to coordinate to pixel position.
copy(**kwargs)	Copy MapAxis instance and overwrite given attributes.
downsample()
format_plot_xaxis(ax)	Format plot axis
from_gti(gti[, name])	Create a time axis from an input GTI.
from_gti_bounds(gti, t_delta[, name])	Create a time axis from an input GTI.
from_table(table[, format, idx])	Create time map axis from table
from_time_bounds(time_min, time_max, nbin[, ...])	Create linearly spaced time axis from bounds
from_time_edges(time_min, time_max[, unit, ...])	Create TimeMapAxis from the time interval edges defined as Time.
is_aligned(other[, atol])
is_allclose(other, **kwargs)	Check if other map axis is all close.
pix_to_idx(pix[, clip])
slice(idx)	Create a new axis object by extracting a slice from this axis.
squash()	Create a new axis object by squashing the axis into one bin.
to_contiguous()	Make the time axis contiguous
to_header([format, idx])	Create FITS header
upsample()

Attributes Documentation

as_plot_center

Plot center

as_plot_edges

Plot edges

as_plot_labels

Plot labels

as_plot_xerr

Plot x error

bin_width

Return time interval width (Quantity).

bounds

Bounds of the axis (~astropy.units.Quantity)

center

Return Quantity at interval centers.

edges

Return array of bin edges values.

edges_max

Return array of bin edges min values.

edges_min

Return array of bin edges max values.

interp

Interp

is_contiguous

Whether the axis is contiguous

iter_by_edges

Iterate by intervals defined by the edges

name

Return axis name.

nbin

Return number of bins in the axis.

node_type = 'intervals'

reference_time

Return reference time used for the axis.

time_bounds

Bounds of the axis (~astropy.units.Quantity)

time_delta

Return axis time bin width (TimeDelta).

time_edges

Time edges

time_format = 'iso'

time_max

Return axis upper edges as Time objects.

time_mid

Return time bin center (Time).

time_min

Return axis lower edges as Time objects.

unit

Axes unit

Methods Documentation

assert_name(required_name)

Assert axis name if a specific one is required.

Parameters

required_namestr

Required

coord_to_idx(coord, **kwargs)

Transform from axis time coordinate to bin index.

Indices of time values falling outside time bins will be set to -1.

Parameters

coordTime or Quantity

Array of axis coordinate values. The quantity is assumed to be relative to the reference time.

Returns

idxndarray

Array of bin indices.

coord_to_pix(coord, **kwargs)

Transform from time to coordinate to pixel position.

Pixels of time values falling outside time bins will be set to -1.

Parameters

coordTime

Array of axis coordinate values.

Returns

pixndarray

Array of pixel positions.

copy(**kwargs)

Copy MapAxis instance and overwrite given attributes.

Parameters

**kwargsdict

Keyword arguments to overwrite in the map axis constructor.

Returns

copyMapAxis

Copied map axis.

downsample()

format_plot_xaxis(ax)

Format plot axis

Parameters

axAxis

Plot axis to format

Returns

axAxis

Formatted plot axis

classmethod from_gti(gti, name='time')

Create a time axis from an input GTI.

Parameters

gtiGTI

GTI table

namestr

Axis name

Returns

axisTimeMapAxis

Time map axis.

classmethod from_gti_bounds(gti, t_delta, name='time')

Create a time axis from an input GTI.

The unit for the axis is taken from the t_delta quantity.

Parameters

gtiGTI

GTI table

t_deltaQuantity

Time binning

namestr

Axis name

Returns

axisTimeMapAxis

Time map axis.

classmethod from_table(table, format='gadf', idx=0)

Create time map axis from table

Parameters

tableTable

Bin table HDU

format{“gadf”, “fermi-fgl”, “lightcurve”}

Format to use.

Returns

axisTimeMapAxis

Time map axis.

classmethod from_time_bounds(time_min, time_max, nbin, unit='d', name='time')

Create linearly spaced time axis from bounds

Parameters

time_minTime

Lower bound

time_maxTime

Upper bound

nbinint

Number of bins

namestr

Name of the axis.

classmethod from_time_edges(time_min, time_max, unit='d', interp='lin', name='time')

Create TimeMapAxis from the time interval edges defined as Time.

The reference time is defined as the lower edge of the first interval.

Parameters

time_minTime

Array of lower edge times.

time_maxTime

Array of lower edge times.

unitUnit or str

The unit to convert the edges to. Default is ‘d’ (day).

interpstr

Interpolation method used to transform between axis and pixel coordinates. Currently, only ‘lin’ is supported.

namestr

Axis name

Returns

axisTimeMapAxis

Time map axis.

is_aligned(other, atol=0.02)

is_allclose(other, **kwargs)

Check if other map axis is all close.

Parameters

otherTimeMapAxis

Other map axis

**kwargsdict

Keyword arguments forwarded to allclose

Returns

is_allclosebool

Whether other axis is allclose

static pix_to_idx(pix, clip=False)

slice(idx)

Create a new axis object by extracting a slice from this axis.

Parameters

idxslice

Slice object selecting a subselection of the axis.

Returns

axisTimeMapAxis

Sliced axis object.

squash()

Create a new axis object by squashing the axis into one bin.

Returns

axisMapAxis

Sliced axis object.

to_contiguous()

Make the time axis contiguous

Returns

axisTimeMapAxis

Contiguous time axis

to_header(format='gadf', idx=0)

Create FITS header

Parameters

format{“ogip”}

Format specification

idxint

Column index of the axis.

Returns

headerHeader

Header to extend.

upsample()