使用python生成RA与DEC赤道坐标图
我正在尝试生成一个看起来或多或少像这样的赤道坐标图：
（该图来自this article，它显示赤道坐标中Large and Small MCs的位置）
关于这个情节需要注意的重要事项：
-
theta轴（即：右上角）位于 h：m：s （小时，分钟，秒），因为它习惯于天文学，而不是度数默认polar选项位于matplotlib。 -
r轴（即：赤纬）从-90º向外增加，网格以（0h，-90º）为中心。 - 该图是剪裁，这意味着只有一部分显示而不是整个圆圈（默认为
matplotlib）。
使用polar=True中的matplotlib选项，我设法生成的最接近的地块是（MWE以下，数据文件here;某些点不存在与上面的图像相比，因为数据文件有点小）：
我还需要在绘图中添加第三列数据，这就是为什么我相应地为z数组添加颜色条和颜色的原因：
所以我现在最需要的是一种剪辑情节的方法。主要基于this question和this example @cphlewis与his answer非常接近，但有些事情仍然缺失（在他的回答中提到）。
非常感谢任何有关此问题的帮助和/或指示。
MWE
（注意我使用gridspec来定位子图，因为我需要在同一输出图像文件中生成其中的几个）
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec
def skip_comments(f):
'''
Read lines that DO NOT start with a # symbol.
'''
for line in f:
if not line.strip().startswith('#'):
yield line
def get_data_bb():
'''RA, DEC data file.
'''
# Path to data file.
out_file = 'bb_cat.dat'
# Read data file
with open(out_file) as f:
ra, dec = [], []
for line in skip_comments(f):
ra.append(float(line.split()[0]))
dec.append(float(line.split()[1]))
return ra, dec
# Read RA, DEC data from file.
ra, dec = get_data_bb()
# Convert RA from decimal degrees to radians.
ra = [x / 180.0 * 3.141593 for x in ra]
# Make plot.
fig = plt.figure(figsize=(20, 20))
gs = gridspec.GridSpec(4, 2)
# Position plot in figure using gridspec.
ax = plt.subplot(gs[0], polar=True)
ax.set_ylim(-90, -55)
# Set x,y ticks
angs = np.array([330., 345., 0., 15., 30., 45., 60., 75., 90., 105., 120.])
plt.xticks(angs * np.pi / 180., fontsize=8)
plt.yticks(np.arange(-80, -59, 10), fontsize=8)
ax.set_rlabel_position(120)
ax.set_xticklabels(['$22^h$', '$23^h$', '$0^h$', '$1^h$', '$2^h$', '$3^h$',
'$4^h$', '$5^h$', '$6^h$', '$7^h$', '$8^h$'], fontsize=10)
ax.set_yticklabels(['$-80^{\circ}$', '$-70^{\circ}$', '$-60^{\circ}$'],
fontsize=10)
# Plot points.
ax.scatter(ra, dec, marker='o', c='k', s=1, lw=0.)
# Use this block to generate colored points with a colorbar.
#cm = plt.cm.get_cmap('RdYlBu_r')
#z = np.random.random((len(ra), 1)) # RGB values
#SC = ax.scatter(ra, dec, marker='o', c=z, s=10, lw=0., cmap=cm)
# Colorbar
#cbar = plt.colorbar(SC, shrink=1., pad=0.05)
#cbar.ax.tick_params(labelsize=8)
#cbar.set_label('colorbar', fontsize=8)
# Output png file.
fig.tight_layout()
plt.savefig(ra_dec_plot.png', dpi=300)
3 个答案:
答案 0 :(得分：6)
咀嚼AxisArtist的例子实际上非常有前景（这结合了两个AxisArtist的例子 - 如果AxisArtist用RA情节编写，我不会感到惊讶）：
还在做：
- 赤字应该从原点的-90到0
- 能够使用 并添加一个颜色栏
- 如果在他们之外绘图，则调整限制
- 轴标签中的衬线字体
- 提升的虚线网格
审美：
其他什么？
"""
An experimental support for curvilinear grid.
"""
import numpy as np
import mpl_toolkits.axisartist.angle_helper as angle_helper
import matplotlib.cm as cmap
from matplotlib.projections import PolarAxes
from matplotlib.transforms import Affine2D
from mpl_toolkits.axisartist import SubplotHost
from mpl_toolkits.axisartist import GridHelperCurveLinear
def curvelinear_test2(fig):
"""
polar projection, but in a rectangular box.
"""
global ax1
# see demo_curvelinear_grid.py for details
tr = Affine2D().scale(np.pi/180., 1.) + PolarAxes.PolarTransform()
extreme_finder = angle_helper.ExtremeFinderCycle(10, 60,
lon_cycle = 360,
lat_cycle = None,
lon_minmax = None,
lat_minmax = (0, np.inf),
)
grid_locator1 = angle_helper.LocatorHMS(12) #changes theta gridline count
tick_formatter1 = angle_helper.FormatterHMS()
grid_locator2 = angle_helper.LocatorDMS(6)
tick_formatter2 = angle_helper.FormatterDMS()
grid_helper = GridHelperCurveLinear(tr,
extreme_finder=extreme_finder,
grid_locator1=grid_locator1,
tick_formatter1=tick_formatter1,
grid_locator2=grid_locator2,
tick_formatter2=tick_formatter2
)
ax1 = SubplotHost(fig, 1, 1, 1, grid_helper=grid_helper)
# make ticklabels of right and top axis visible.
ax1.axis["right"].major_ticklabels.set_visible(True)
ax1.axis["top"].major_ticklabels.set_visible(True)
ax1.axis["bottom"].major_ticklabels.set_visible(True) #Turn off?
# let right and bottom axis show ticklabels for 1st coordinate (angle)
ax1.axis["right"].get_helper().nth_coord_ticks=0
ax1.axis["bottom"].get_helper().nth_coord_ticks=0
fig.add_subplot(ax1)
grid_helper = ax1.get_grid_helper()
ax1.set_aspect(1.)
ax1.set_xlim(-4,15) # moves the origin left-right in ax1
ax1.set_ylim(-3, 20) # moves the origin up-down
ax1.set_ylabel('90$^\circ$ + Declination')
ax1.set_xlabel('Ascension')
ax1.grid(True)
#ax1.grid(linestyle='--', which='x') # either keyword applies to both
#ax1.grid(linestyle=':', which='y') # sets of gridlines
return tr
import matplotlib.pyplot as plt
fig = plt.figure(1, figsize=(5, 5))
fig.clf()
tr = curvelinear_test2(fig) # tr.transform_point((x, 0)) is always (0,0)
# => (theta, r) in but (r, theta) out...
r_test = [0, 1.2, 2.8, 3.8, 5, 8, 10, 13.3, 17] # distance from origin
deg_test = [0, -7, 12, 28, 45, 70, 79, 90, 100] # degrees ascension
out_test = tr.transform(zip(deg_test, r_test))
sizes = [40, 30, 10, 30, 80, 33, 12, 48, 45]
#hues = [.9, .3, .2, .8, .6, .1, .4, .5,.7] # Oddly, floats-to-colormap worked for a while.
hues = np.random.random((9,3)) #RGB values
ax1.scatter(out_test[:,0], #ax1 is a global
out_test[:,1],
s=sizes,
c=hues,
#cmap=cmap.RdYlBu_r,
zorder=9) #on top of gridlines
plt.show()
答案 1 :(得分：5)
获取颜色栏可以通过将OP代码与@cphlewis's excellent answer合并来完成。我已将此作为request of the OP in chat的交钥匙解决方案发布。第一个版本的代码只添加一个颜色条，最终版本（在编辑2下）执行轴仿射转换并纠正一些参数/简化代码以完全符合OP规范。
"""
An experimental support for curvilinear grid.
"""
import numpy as np
import mpl_toolkits.axisartist.angle_helper as angle_helper
import matplotlib.cm as cmap
from matplotlib.projections import PolarAxes
from matplotlib.transforms import Affine2D
from mpl_toolkits.axisartist import SubplotHost
from mpl_toolkits.axisartist import GridHelperCurveLinear
def curvelinear_test2(fig):
"""
polar projection, but in a rectangular box.
"""
global ax1
# see demo_curvelinear_grid.py for details
tr = Affine2D().scale(np.pi/180., 1.) + PolarAxes.PolarTransform()
extreme_finder = angle_helper.ExtremeFinderCycle(10, 60,
lon_cycle = 360,
lat_cycle = None,
lon_minmax = None,
lat_minmax = (0, np.inf),
)
grid_locator1 = angle_helper.LocatorHMS(12) #changes theta gridline count
tick_formatter1 = angle_helper.FormatterHMS()
grid_locator2 = angle_helper.LocatorDMS(6)
tick_formatter2 = angle_helper.FormatterDMS()
grid_helper = GridHelperCurveLinear(tr,
extreme_finder=extreme_finder,
grid_locator1=grid_locator1,
tick_formatter1=tick_formatter1,
grid_locator2=grid_locator2,
tick_formatter2=tick_formatter2
)
ax1 = SubplotHost(fig, 1, 1, 1, grid_helper=grid_helper)
# make ticklabels of right and top axis visible.
ax1.axis["right"].major_ticklabels.set_visible(True)
ax1.axis["top"].major_ticklabels.set_visible(True)
ax1.axis["bottom"].major_ticklabels.set_visible(True) #Turn off?
# let right and bottom axis show ticklabels for 1st coordinate (angle)
ax1.axis["right"].get_helper().nth_coord_ticks=0
ax1.axis["bottom"].get_helper().nth_coord_ticks=0
fig.add_subplot(ax1)
grid_helper = ax1.get_grid_helper()
ax1.set_aspect(1.)
ax1.set_xlim(-4,15) # moves the origin left-right in ax1
ax1.set_ylim(-3, 20) # moves the origin up-down
ax1.set_ylabel('90$^\circ$ + Declination')
ax1.set_xlabel('Ascension')
ax1.grid(True)
#ax1.grid(linestyle='--', which='x') # either keyword applies to both
#ax1.grid(linestyle=':', which='y') # sets of gridlines
return tr
import matplotlib.pyplot as plt
fig = plt.figure(1, figsize=(5, 5))
fig.clf()
tr = curvelinear_test2(fig) # tr.transform_point((x, 0)) is always (0,0)
# => (theta, r) in but (r, theta) out...
r_test = [0, 1.2, 2.8, 3.8, 5, 8, 10, 13.3, 17] # distance from origin
deg_test = [0, -7, 12, 28, 45, 70, 79, 90, 100] # degrees ascension
out_test = tr.transform(zip(deg_test, r_test))
sizes = [40, 30, 10, 30, 80, 33, 12, 48, 45]
#hues = [.9, .3, .2, .8, .6, .1, .4, .5,.7] # Oddly, floats-to-colormap worked for a while.
hues = np.random.random((9,3)) #RGB values
# Use this block to generate colored points with a colorbar.
cm = plt.cm.get_cmap('RdYlBu_r')
z = np.random.random((len(r_test), 1)) # RGB values
SC = ax1.scatter(out_test[:,0], #ax1 is a global
out_test[:,1],
s=sizes,
c=z,
cmap=cm,
zorder=9) #on top of gridlines
# Colorbar
cbar = plt.colorbar(SC, shrink=1., pad=0.05)
cbar.ax.tick_params(labelsize=8)
cbar.set_label('colorbar', fontsize=8)
plt.show()
<强> 修改
整理参数，添加OP数据，删除冗余会产生以下图表。仍然需要将数据集中在-90而不是0 - 目前这是被黑客攻击的，但我确信curvelinear_test2()可以更改为帐户...
编辑2
在这个答案中关于中间版本的OP评论之后，下面的最终版本给出了帖子最后的情节 - 在dec轴上的-90和子图演示
"""
An experimental support for curvilinear grid.
"""
import numpy as np
import mpl_toolkits.axisartist.angle_helper as angle_helper
import matplotlib.cm as cmap
from matplotlib.projections import PolarAxes
from matplotlib.transforms import Affine2D
from mpl_toolkits.axisartist import SubplotHost
from mpl_toolkits.axisartist import GridHelperCurveLinear
def curvelinear_test2(fig, rect=111):
"""
polar projection, but in a rectangular box.
"""
# see demo_curvelinear_grid.py for details
tr = Affine2D().translate(0,90) + Affine2D().scale(np.pi/180., 1.) + PolarAxes.PolarTransform()
extreme_finder = angle_helper.ExtremeFinderCycle(10, 60,
lon_cycle = 360,
lat_cycle = None,
lon_minmax = None,
lat_minmax = (-90, np.inf),
)
grid_locator1 = angle_helper.LocatorHMS(12) #changes theta gridline count
tick_formatter1 = angle_helper.FormatterHMS()
grid_helper = GridHelperCurveLinear(tr,
extreme_finder=extreme_finder,
grid_locator1=grid_locator1,
tick_formatter1=tick_formatter1
)
ax1 = SubplotHost(fig, rect, grid_helper=grid_helper)
# make ticklabels of right and top axis visible.
ax1.axis["right"].major_ticklabels.set_visible(True)
ax1.axis["top"].major_ticklabels.set_visible(True)
ax1.axis["bottom"].major_ticklabels.set_visible(True) #Turn off?
# let right and bottom axis show ticklabels for 1st coordinate (angle)
ax1.axis["right"].get_helper().nth_coord_ticks=0
ax1.axis["bottom"].get_helper().nth_coord_ticks=0
fig.add_subplot(ax1)
grid_helper = ax1.get_grid_helper()
# You may or may not need these - they set the view window explicitly rather than using the
# default as determined by matplotlib with extreme finder.
ax1.set_aspect(1.)
ax1.set_xlim(-4,25) # moves the origin left-right in ax1
ax1.set_ylim(-3, 30) # moves the origin up-down
ax1.set_ylabel('Declination')
ax1.set_xlabel('Ascension')
ax1.grid(True)
#ax1.grid(linestyle='--', which='x') # either keyword applies to both
#ax1.grid(linestyle=':', which='y') # sets of gridlines
return ax1,tr
def skip_comments(f):
'''
Read lines that DO NOT start with a # symbol.
'''
for line in f:
if not line.strip().startswith('#'):
yield line
def get_data_bb():
'''RA, DEC data file.
'''
# Path to data file.
out_file = 'bb_cat.dat'
# Read data file
with open(out_file) as f:
ra, dec = [], []
for line in skip_comments(f):
ra.append(float(line.split()[0]))
dec.append(float(line.split()[1]))
return ra, dec
import matplotlib.pyplot as plt
fig = plt.figure(1, figsize=(5, 5))
fig.clf()
ax1, tr = curvelinear_test2(fig,121) # tr.transform_point((x, 0)) is always (0,0)
# => (theta, r) in but (r, theta) out...
# Read RA, DEC data from file.
ra, dec = get_data_bb()
out_test = tr.transform(zip(ra, dec))
# Use this block to generate colored points with a colorbar.
cm = plt.cm.get_cmap('RdYlBu_r')
z = np.random.random((len(ra), 1)) # RGB values
SC = ax1.scatter(out_test[:,0], #ax1 is a global
out_test[:,1],
marker = 'o',
c=z,
cmap=cm,
lw = 0.,
zorder=9) #on top of gridlines
# Colorbar
cbar = plt.colorbar(SC, shrink=1., pad=0.1)
cbar.ax.tick_params(labelsize=8)
cbar.set_label('colorbar', fontsize=8)
ax2, tr = curvelinear_test2(fig,122) # tr.transform_point((x, 0)) is always (0,0)
# => (theta, r) in but (r, theta) out...
# Read RA, DEC data from file.
ra, dec = get_data_bb()
out_test = tr.transform(zip(ra, dec))
# Use this block to generate colored points with a colorbar.
cm = plt.cm.get_cmap('RdYlBu_r')
z = np.random.random((len(ra), 1)) # RGB values
SC = ax2.scatter(out_test[:,0], #ax1 is a global
out_test[:,1],
marker = 'o',
c=z,
cmap=cm,
lw = 0.,
zorder=9) #on top of gridlines
# Colorbar
cbar = plt.colorbar(SC, shrink=1., pad=0.1)
cbar.ax.tick_params(labelsize=8)
cbar.set_label('colorbar', fontsize=8)
plt.show()
最终情节：
答案 2 :(得分：0)
我认为这可能是 Python 3+ 的问题，现在该行了
out_test = tr.transform(zip(deg_test, r_test))
返回错误：
ValueError: 无法将大小为 1 的数组重塑为形状 (2)
换行
out_test = tr.transform(list(zip(deg_test, r_test)))
修复了问题并允许正确生成绘图。
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