syrte/sky_map.md

## sky_map.md

      
    Raw
  

              sky_map.md
            
          
    import numpy as np
import proplot as pplt
from matplotlib import pyplot as plt
import cartopy.geodesic


def add_ticks(ax, labelpad=None):
    """
    Only works for major ticks on the left and bottom.
    """
    ax.grid(False)  # prevent redundancy grids
    ax.tick_params('both', which='major', size=pplt.rc['tick.len'])
    if labelpad is None:
        labelpad = pplt.rc['tick.len'] + 2

    for gl in ax._gridliners:
        gl.xpadding = gl.ypadding = labelpad  # for gridliners initialized outside ax.format
    ax.format(labelpad=labelpad)

    ax.figure.canvas.draw_idle()  # necessary for generating xlabel_artists...
    for gl in ax._gridliners:
        tk = np.array([t.get_position()[0] for t in gl.bottom_label_artists if t.get_visible()])
        if tk.any():
            ax.set_xticks(tk)
            ax.set_xticklabels([])

        tk = np.array([t.get_position()[1] for t in gl.left_label_artists if t.get_visible()])
        if tk.any():
            ax.set_yticks(tk)
            ax.set_yticklabels([])


def add_label(ax, xlabel=None, ylabel=None, xlabelpad=13, ylabelpad=13):
    if xlabel:
        ax.xaxis.set_visible(True)  # cartopy sets this to False
        ax.set_xlabel(xlabel, labelpad=xlabelpad)
    if ylabel:
        ax.yaxis.set_visible(True)
        ax.set_ylabel(ylabel, labelpad=ylabelpad)


def add_circle(ax, lon, lat, radius, npts=100, **kwargs):
    """
    lon, lat:
        center
    radius:
        in unit of rad
    """
    pts = cartopy.geodesic.Geodesic(1, 0).circle(lon=lon, lat=lat, radius=radius)
    return ax.fill(*pts.T, transform=pplt.PlateCarree(), **kwargs)


fig = pplt.figure(span=False, suptitle='Example')

ax = fig.subplot(121, proj='gnom', proj_kw={'lon_0': 0, 'lat_0': 45})
ax.format(lonlim=(-20, 20), latlim=(30, 60),
          labels=True, grid=True, gridminor=True,
          lonlocator=np.arange(-50, 50, 5), latlocator=5,
          latformatter="simple", lonformatter="simple",
          )
add_ticks(ax)
add_label(ax, xlabel='ra', ylabel='dec')
add_circle(ax, lon=15, lat=55, radius=0.2, fc='lightblue', alpha=0.5)

x = np.random.uniform(-10, 10, 100)
y = np.random.uniform(40, 60, 100)
ax.scatter(x, y, s=20)


ax2 = fig.subplot(122)
ax2.format(xlim=(-20, 20), ylim=(-20, 20),
           xlabel='xdata', ylabel='ydata')
Result