Skymap

This module allows to easily plot arrival directions of events or healpy maps.

Module to visualize arrival directions or heatmaps on the sphere.

class skymap.PlotSkyPatch(lon_roi, lat_roi, r_roi, ax=None, title=None, **kwargs)

Bases: object

Class to plot a close-up look of a region of interest (ROI) in the sky. To use this class you need to install the Basemap package: https://matplotlib.org/basemap/users/installing.html

from astrotools.skymap import PlotSkyPatch
patch = PlotSkyPatch(lon0, lat0, r_roi, title='My Skypatch')
mappable = patch.plot_crs("/path/to/cosmic_rays.CosmicRaysSets.npz", set_idx=0)
patch.mark_roi()
patch.plot_grid()
patch.colorbar(mappable)
patch.savefig("/tmp/test-skypatch.png")

colorbar(mappable, cblabel='Energy [eV]', labelsize=12, ticks=None, **kwargs)

Adds a colorbar to a mappable in matplotlib. Replaces matplotlib colorbar() function. Use e.g:

patch = PlotSkyPatch(…) mappable = patch.plot_crs(crs) patch.colorbar(mappable)

Parameters

• mappable – Mappable in matplotlib.

• clabel – Label for the colorbar

• ticks – Ticks for the colorbar (either array-like or integer for number of ticks)

• kwargs – Keywords passed to matplotlib colorbar() function

mark_roi(alpha=0.4, **kwargs)

Marks the ROI by a circle ans shades cosmic rays outside the ROI.

Parameters

kwargs – Passed to Basemaps tissot() function

mark_roi_center(**kwargs)

Mark the ROI center

Parameters

kwargs – keywords for matplotlib.pyplot.plot() function

plot(lons, lats, **kwargs)

Replaces matplotlib.pyplot.plot() function

plot_crs(crs, set_idx=0, zorder=0, cmap='viridis', **kwargs)

Plot cosmic ray events in the sky.

Parameters

• crs – Either cosmic_rays.CosmicRaysBase or cosmic_rays.CosmicRaysSets object (or path) or dict object

• set_idx – In case of CosmicRaysSets object, chose the respective set index

• zorder – Usual matplotlib zorder keyword (order of plotting)

• cmap – Matplotlib colormap object or string

plot_grid(meridians=None, parallels=None, mer_labels=None, par_labels=None)

Plot the longitude and latitude grid in the skypatch

plot_thrust(n, t, **kwargs)

Visualize the thrust observables in the ROI.

Parameters

• n – Thrust axis as given by astrotools.obs.thrust()[1]

• t – Thrust values as returned by astrotools.obs.thrust()[0]

• kwargs – Keywords passed to matplotlib.pyplot.plot() for axis visualization

savefig(path, **kwargs)

Substitudes matplotlib savefig() function

scatter(lons, lats, **kwargs)

Replaces matplotlib.pyplot.scatter() function

text(x, y, s, **kwargs)

Substitudes matplotlib.pyplot.text() function

tissot(lon, lat, radius, npts=1000, **kwargs)

Replaces the Basemap tissot() function (plot circles)

skymap.heatmap(m, opath=None, label='entries', mask=None, maskcolor='white', tophat_smoothing=None, gaussian_smoothing=None, no_cb=False, **kwargs)

Heatmap plot of binned data m. For exmaple usage see: cosmic_rays.plot_healpy_map()

Parameters

• m – Array with size npix for an arbitrary healpy nside.

• opath – if not None, saves the figure to the given opath (no returns)

• label – label for the colormap

• mask – either boolean mask that paints certain pixels different or condition for m

• maskcolor – which color to paint the mask

• tophat_smoothing – if number: smooth map with tophat filter of that size in degree

• tophat_smoothing – if number: smooth map with Gaussian filter of that size in degree

• kwargs – additional named keyword arguments (non-listed keywords are passed to matplotlib.pcolormesh)

• no_cb –

  disables color bar

  • figsize: figure size as input for plt.figure()

  • cmap: colormap

  • vmin: Lower cut of the colorbar scale

  • vmax: Upper cut of the colorbar scale

  • cbticks: Ticks of the colorbar

  • mask_alpha: alpha value for maskcolor

  • fontsize: scale the general fontsize

  • xresolution: Scales the resolution of the plot (default: 800)

  • dark_grid: if True paints a dark grid (useful for bright maps)

  • gridcolor: Color of the grid.

  • gridalpha: Transparency value of the gridcolor.

  • tickcolor: Color of the ticks.

  • tickalpha: Transparency of the longitude ticks.

  • plane: plots ‘SGP’ or ‘GP’ or both (list) into plot

  • planecolor: color of plane

  • coord_system: default galactic (‘gal’) / equatorial (‘eq’)

Returns

figure of the heatmap, colorbar

skymap.plot_grid(lon_ticks=None, lat_ticks=None, lon_grid=30, lat_grid=30, fontsize=26, **kwargs)

Plot a grid on the skymap.

Parameters

• lon_ticks – Set the label ticks for the longitudes (default: [90, 0, -90]).

• lat_ticks – Set the label ticks for the latitude (default: [-60, -30, 0, 30, 60]).

• lon_grid – Distances between the grid lines in longitude in degrees (default: 30 deg).

• lat_grid – Distances between the grid lines in latitude in degrees (default: 30 deg).

• kwargs –

  additional named keyword arguments

  • gridcolor: Color of the grid.

  • gridalpha: Transparency value of the gridcolor.

  • tickcolor: Color of the ticks.

  • tickalpha: Transparency of the longitude ticks.

skymap.plot_plane(planecolor=0.5, coord_system='gal', plane='SGP', zorder=- 10, **kwargs)

Plot a the supergalactic plane onto skymap.

Parameters

• planecolor – color of plane

• coord_system – default galactic (‘gal’) / equatorial (‘eq’)

• plane – plots ‘SGP’ or ‘GAL’ or both (list) into plot

• kwargs – additional named keyword arguments passed to plt.plot()

• zorder – which layer to plot the plane (-10 for behind, +10 for before everything else)

skymap.plot_tissot(vec_c, r, res=0.01, **kwargs)

Plot a circle onto skymap.

Parameters

• vec_c – vector pointing to the center of the circle

• r – radius of the circle

• res – resolution of the circle approximation (in radian)

• kwargs – additional named keyword arguments passed to plt.plot()

skymap.scatter(v, c=None, cblabel='log$_{10}$(Energy / eV)', opath=None, fig=None, **kwargs)

Scatter plot of events with arrival directions x,y,z and colorcoded energies.

Parameters

• v – array of shape (3, n) pointing into directions of the events

• c – quantity that is supposed to occur in colorbar, e.g. energy of the cosmic rays

• cblabel – colorbar label

• opath – if not None, saves the figure to the given opath (no returns)

• fig – figure to plot in, creates new figure if None

• kwargs –

  additional named keyword arguments

  • figsize: figure size as input for plt.figure()

  • cmap: colormap

  • cbar: if True includes a colobar

  • cticks: sets ticks of colormap

  • mask_alpha: alpha value for maskcolor

  • fontsize: scale the general fontsize

  • dark_grid: if True paints a dark grid (useful for bright maps)

  • gridcolor: Color of the grid.

  • gridalpha: Transparency value of the gridcolor.

  • tickcolor: Color of the ticks.

  • tickalpha: Transparency of the longitude ticks.

  • plane: plots ‘SGP’ or ‘GP’ or both (list) into plot

  • planecolor: color of plane

  • coord_system: default galactic (‘gal’) / equatorial (‘eq’)

Returns

figure, axis of the scatter plot

skymap.smart_round(v, order=2, upper_border=True)

Rounds a value v such that it can be used e.g. for colorbars

Parameters

• v (int, float) – scalar value which should be rounded

• upper_border – round such that the value can be used as an upper border of an interval, default=True

• order – number of digits to round to, default=2

Returns

rounded value

Return type

int, float

This function has been tested on the following numbers (with all upper_border presented here):

:linenos:
>> from astrotools.skymap import smart_round
>> smart_round(100000), smart_round(100000, upper_border=False)
100000.0, 100000.0
>> smart_round(100001), smart_round(100001, upper_border=False)
101000.0, 100000.0
>> smart_round(-100001), smart_round(-100001, upper_border=False)
-100000.0, -100000.0
>> smart_round(2.23), smart_round(2.23, upper_border=False)
2.23, 2.23
>> smart_round(2.230), smart_round(2.230, upper_border=False)
2.23, 2.23
>> smart_round(2.231), smart_round(2.231, upper_border=False)
2.24, 2.23
>> smart_round(-2.230), smart_round(-2.230, upper_border=False)
-2.23, -2.23
>> smart_round(-2.231), smart_round(-2.231, upper_border=False)
-2.23, -2.24
>> smart_round(0.930001), smart_round(0.930001, upper_border=False)
0.94, 0.93
>> smart_round(-0.930001), smart_round(-0.930001, upper_border=False)
-0.93, -0.94