Python为兰勃脱投影(Lambert)地图添加经纬度刻度（3）

" Created on by Haolishen on 2021.6.2, in TianJin"import numpy as npimport matplotlib.pyplot as pltimport cartopy.crs as ccrsimport cartopy.feature as cfeature  from cartopy.mpl.gridliner import LATITUDE_FORMATTER, LONGITUDE_FORMATTERimport warnings;   warnings.filterwarnings('ignore')plt.rcParams['font.family'] ='Times New Roman'   plt.rcParams['font.size'] = 12                # 自定义获取经纬度刻度位置函数def get_lambert_ticks(ax, ticks0, tick_location):    import shapely.geometry as sgeom    xmin,xmax,ymin,ymax = ax.get_extent()      lonmin,lonmax,latmin,latmax = ax.get_extent(ccrs.PlateCarree())      axises = {'left':   [(xmin, ymin), (xmin, ymax)],'right': [(xmax, ymin), (xmax, ymax)],              'bottom': [(xmin, ymin), (xmax, ymin)],  'top': [(xmin, ymax), (xmax, ymax)],}    line_axis = sgeom.LineString(axises[tick_location])      ticks = []      N = 50      for tick1 in ticks0:        if( (tick_location.upper()=='TOP') | (tick_location.upper()=='BOTTOM')):            xy = np.vstack((np.zeros(N)+tick1, np.linspace(latmin-5, latmax+5, N, endpoint=True))).T        elif( (tick_location.upper()=='LEFT') | (tick_location.upper()=='RIGHT')):            xy = np.vstack((np.linspace(lonmin-5, lonmax+5, N, endpoint=True), np.zeros(N)+tick1)).T        proj_xy = (ax.projection.transform_points(ccrs.Geodetic(), xy[:,0], xy[:,1]))[:,:2]        line_lonlat = sgeom.LineString(proj_xy)           locs = line_axis.intersection(line_lonlat)          if not locs:            tick = [None]        else:            if( (tick_location.upper()=='TOP') | (tick_location.upper()=='BOTTOM')):


    
                tick = locs.xy[0]                 elif( (tick_location.upper()=='LEFT') | (tick_location.upper()=='RIGHT')):                tick = locs.xy[1]           ticks.append(tick[0])      # 去掉看不到的刻度        ticklabels = ticks0    while True:        try:            index = ticks.index(None)        except ValueError:            break        ticks.pop(index)        ticklabels.pop(index)    return ticks, ticklabels# 自定义添加左侧刻度的函数def lambert_yticks_left(ax, ticks, length, width, pad, fontdict=None):    " Draw ticks on the left y-axis of a Lamber Conformal projection. "    yticks, yticklabels = get_lambert_ticks(ax, ticks, 'left')    ax.yaxis.tick_left()    ax.set_yticks(yticks)    ax.set_yticklabels([ax.yaxis.get_major_formatter()(ytick) for ytick in yticklabels],fontdict)    ax.tick_params(axis='y',which='major',direction='out',length=length, width=width, pad=pad)    return# 自定义添加右侧刻度的函数def lambert_yticks_right(ax, ticks,length, width, pad, fontdict=None):    " Draw ticks on the right y-axis of a Lamber Conformal projection. "    yticks, yticklabels = get_lambert_ticks(ax, ticks, 'right')    ax2 = ax.secondary_yaxis('right')    #新建ax3,使ax3与ax2完全相同    ax2.yaxis.tick_right()    ax2.set_yticks(yticks)    ax2.set_yticklabels([ax.yaxis.get_major_formatter()(ytick) for ytick in yticklabels],fontdict)    ax2.tick_params(axis='y',which='major',direction='out',length=length, width=width, pad=pad)    return# 自定义添加底边刻度的函数def lambert_xticks_bottom(ax, ticks, length, width, pad, fontdict=None):    " Draw ticks on the bottom x-axis of a Lambert Conformal projection. "    xticks, xticklabels = get_lambert_ticks(ax, ticks, 'bottom')    ax.xaxis.tick_bottom()    ax.set_xticks(xticks)    ax.set_xticklabels([ax.xaxis.get_major_formatter()(xtick) for xtick in xticklabels],fontdict)    ax.tick_params(axis='x',which='major',direction='out',length=length, width=width, pad=pad)    return# 自定义添加顶部刻度的函数def lambert_xticks_top(ax, ticks, length, width, pad, fontdict=None):    " Draw ticks on the top x-axis of a Lambert Conformal projection. "    xticks, xticklabels = get_lambert_ticks(ax, ticks, 'top')    ax2 = ax.secondary_xaxis('top')    #新建ax3,使ax3与ax2完全相同    ax2.xaxis.tick_top()    ax2.set_xticks(xticks)    ax2.set_xticklabels([ax.xaxis.get_major_formatter()(xtick) for xtick in xticklabels],fontdict)    ax2.tick_params(axis='x',which='major',direction='out',length=length, width=width, pad=pad)    return#-----------------------------------------------------------------------------#  主程序段proj = ccrs.LambertConformal(central_longitude=110,central_latitude=30.0,standard_parallels=(25,47))extent = [80, 135, 17, 53]#2 设置绘图窗口fig = plt.figure(figsize=(8,6))  #创建页面ax = plt.axes(projection=proj)ax.set_extent(extent, crs=ccrs.PlateCarree()) ax.add_feature(cfeature.OCEAN)ax.add_feature(cfeature.LAND)# 添加经纬网格线# 添加经纬度网格和刻度ax.gridlines(draw_labels=None, xlocs=range(0


    
,180,10), ylocs=range(0,90,10), linestyle='--', linewidth=0.25, color='k')xticks = [lon for lon in np.arange(70,160,10)]yticks = [lat for lat in np.arange(0,60,10)]    ax.xaxis.set_major_formatter(LONGITUDE_FORMATTER) ax.yaxis.set_major_formatter(LATITUDE_FORMATTER)fig.canvas.draw()    #这个不能少,调用fig.canvas.draw()函数才能够更新显示lambert_xticks_top(ax, xticks,    length=4, width=1.0, pad=0, fontdict={'family':'Times New Roman','size':12,'color':'k','rotation':0} )  lambert_yticks_right(ax, yticks,  length=4, width=1.0, pad=2, fontdict={'family':'Times New Roman','size':12,'color':'k','rotation':0} )lambert_xticks_bottom(ax, xticks, length=4, width=1.0, pad=2, fontdict={'family':'Times New Roman','size':12,'color':'k','rotation':0} ) lambert_yticks_left(ax, yticks,   length=4, width=1.0, pad=1, fontdict={'family':'Times New Roman','size':12,'color':'k','rotation':0} )plt.savefig(r'cartopy-lambert-loblat.png',dpi=600,bbox_inches='tight')