MapCoord¶

class gammapy.maps.MapCoord(data, coordsys=None, match_by_name=True)[source]¶

Bases: object

Represents a sequence of n-dimensional map coordinates.

Contains coordinates for 2 spatial dimensions and an arbitrary number of additional non-spatial dimensions.

For further information see MapCoord.

Parameters:

data : OrderedDict of ndarray

Dictionary of coordinate arrays.

coordsys : {‘CEL’, ‘GAL’, None}

Spatial coordinate system. If None then the coordinate system will be set to the native coordinate system of the geometry.

match_by_name : bool

Match coordinates to axes by name? If false coordinates will be matched by index.

Attributes Summary

`coordsys`	Coordinate system (str)
`lat`	Latitude coordinate in degrees.
`lon`	Longitude coordinate in degrees.
`match_by_name`	Boolean flag indicating whether axis lookup should be performed by name (True) or index (False).
`ndim`	Number of dimensions.
`phi`	Phi longitude angle in radians
`shape`	Coordinate array shape.
`size`
`skycoord`
`theta`	Theta co-latitude angle in radians

Methods Summary

`apply_mask`(mask)	Return a masked copy of this coordinate object.
`copy`()	Copy `MapCoord` object.
`create`(data[, coordsys])	Create a new `MapCoord` object.
`match_axes_units`(geom)	Match the units of the non-spatial axes to a given map geometry.
`to_coordsys`(coordsys)	Convert to a different coordinate frame.

Attributes Documentation

coordsys¶: Coordinate system (str)

lat¶: Latitude coordinate in degrees.

lon¶: Longitude coordinate in degrees.

match_by_name¶: Boolean flag indicating whether axis lookup should be performed by name (True) or index (False).

ndim¶: Number of dimensions.

phi¶: Phi longitude angle in radians

shape¶: Coordinate array shape.

size¶

skycoord¶

theta¶: Theta co-latitude angle in radians

Methods Documentation

apply_mask(mask)[source]¶

Return a masked copy of this coordinate object.

Parameters:

mask : ndarray

Boolean mask.

Returns:

coords : MapCoord

A coordinates object.

copy()[source]¶: Copy MapCoord object.

classmethod create(data, coordsys=None)[source]¶

Create a new MapCoord object.

This method can be used to create either unnamed (with tuple input) or named (via dict input) axes.

Parameters:

data : tuple, dict, MapCoord or SkyCoord

Object containing coordinate arrays.

coordsys : {‘CEL’, ‘GAL’, None}, optional

Set the coordinate system for longitude and latitude. If None longitude and latitude will be assumed to be in the coordinate system native to a given map geometry.

Examples

>>> from astropy.coordinates import SkyCoord
>>> from gammapy.maps import MapCoord

>>> lon, lat = [1, 2], [2, 3]
>>> skycoord = SkyCoord(lon, lat, unit='deg')
>>> energy = [1000]
>>> c = MapCoord.create((lon,lat))
>>> c = MapCoord.create((skycoord,))
>>> c = MapCoord.create((lon,lat,energy))
>>> c = MapCoord.create(dict(lon=lon,lat=lat))
>>> c = MapCoord.create(dict(lon=lon,lat=lat,energy=energy))
>>> c = MapCoord.create(dict(skycoord=skycoord,energy=energy))

match_axes_units(geom)[source]¶

Match the units of the non-spatial axes to a given map geometry.

Parameters:

geom : MapGeom

Map geometry with specified units per axis.

Returns:

coords : MapCoord

Map coord object with matched units

to_coordsys(coordsys)[source]¶

Convert to a different coordinate frame.

Parameters:

coordsys : {‘CEL’, ‘GAL’}

Coordinate system, either Galactic (‘GAL’) or Equatorial (‘CEL’).

Returns:

coords : MapCoord

A coordinates object.