# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""Helper functions and functions for plotting gamma-ray images."""
import numpy as np
from astropy.coordinates import Angle
__all__ = ["MapPanelPlotter"]
__doctest_requires__ = {("colormap_hess", "colormap_milagro"): ["matplotlib"]}
[docs]class MapPanelPlotter:
"""
Map panel plotter class.
Given a `~matplotlib.pyplot.Figure` object this class creates axes objects
using `~matplotlib.gridspec.GridSpec` and plots a given sky map onto these.
Parameters
----------
figure : `~matplotlib.pyplot.figure.`
Figure instance.
xlim : `~astropy.coordinates.Angle`
Angle object specifying the longitude limits.
ylim : `~astropy.coordinates.Angle`
Angle object specifying the latitude limits.
npanels : int
Number of panels.
**kwargs : dict
Keyword arguments passed to `~matplotlib.gridspec.GridSpec`.
"""
def __init__(self, figure, xlim, ylim, npanels=4, **kwargs):
from matplotlib.gridspec import GridSpec
self.figure = figure
self.parameters = {"xlim": xlim, "ylim": ylim, "npanels": npanels}
self.grid_spec = GridSpec(nrows=npanels, ncols=1, **kwargs)
def _get_ax_extend(self, ax, panel):
"""Get width and height of the axis in world coordinates."""
p = self.parameters
# compute aspect ratio of the axis
aspect = ax.bbox.width / ax.bbox.height
# compute width and height in world coordinates
height = np.abs(p["ylim"].diff())
width = aspect * height
left, bottom = p["xlim"][0].wrap_at("180d"), p["ylim"][0]
width_all = np.abs(p["xlim"].wrap_at("180d").diff())
xoverlap = ((p["npanels"] * width) - width_all) / (p["npanels"] - 1.0)
if xoverlap < 0:
raise ValueError(
"No overlap between panels. Please reduce figure "
"height or increase vertical space between the panels."
)
left = left - panel * (width - xoverlap)
return left[0], bottom, width, height
def _set_ax_fov(self, ax, panel):
left, bottom, width, height = self._get_ax_extend(ax, panel)
# set fov
xlim = Angle([left, left - width])
ylim = Angle([bottom, bottom + height])
xlim_pix, ylim_pix = ax.wcs.wcs_world2pix(xlim.deg, ylim.deg, 1)
ax.set_xlim(*xlim_pix)
ax.set_ylim(*ylim_pix)
return ax
[docs] def plot_panel(self, map, panel=1, panel_fov=None, **kwargs):
"""
Plot sky map on one panel.
Parameters
----------
map : `~gammapy.maps.WcsNDMap`
Map to plot.
panel : int
Which panel to plot on (counted from top).
"""
if panel_fov is None:
panel_fov = panel
spec = self.grid_spec[panel]
ax = self.figure.add_subplot(spec, projection=map.geom.wcs)
try:
ax = map.plot(ax=ax, **kwargs)
except AttributeError:
ax = map.plot_rgb(ax=ax, **kwargs)
ax = self._set_ax_fov(ax, panel_fov)
return ax
[docs] def plot(self, map, **kwargs):
"""
Plot sky map on all panels.
Parameters
----------
map : `~gammapy.maps.WcsNDMap`
Map to plot.
"""
p = self.parameters
axes = []
for panel in range(p["npanels"]):
ax = self.plot_panel(map, panel=panel, **kwargs)
axes.append(ax)
return axes