Cartopy画地图第七天（python画浮雕地图和比例尺）

本文利用了python、cartopy进行了浮雕地图的绘制，同时还画了比例尺。
先上图为敬，一些图例符号不对请不要介意，随便表示的

第一、下载浮雕地图

想画浮雕地图的朋友们，第一步首先是要下载到浮雕地图文件，网站是Natural Earth，网址是：https://www.naturalearthdata.com/downloads/

只有1：10和1：50的有浮雕地图，就是第三个选项“栅格”（别问为啥我是中文的，问我就告诉你我是浏览器翻译的。）
点进去之后找自己需要的下载就好了，反正我的电脑1：10里面最大的那个地图画不了，报错显示地图太大，其他都没问题，大家自己按实际情况下载就好了。

下载完成以后是一个压缩包，解压得到里面的xxxxx.tif文件就好了，放到代码目录下就能使用。

第二、画浮雕地图

其实没啥难度，就是告诉大家cartopy是可以画浮雕地图的

    #地图四周经纬度west = 110east = 125south = 20north = 30#解决中文乱码问题plt.rcParams['font.sans-serif'] = ['SimHei']#画布设置，投影设置fig = plt.figure(figsize=(16,9.6))ax = fig.add_subplot(111,projection = ccrs.PlateCarree())#边界设置img_extent = [west, east, south, north]ax.set_extent(img_extent,crs = ccrs.PlateCarree())#浮雕地图导入fname = 'HYP_LR_SR_OB_DR.tif'ax.imshow(plt.imread(fname), origin='upper', transform=ccrs.PlateCarree(),extent=[-180, 180, -90, 90])

有些朋友到这里就OK了。

第三、地图美画

经纬度网格设置

 #设置经纬度网格和标签，透明度改成1，就会出现网格 alpha=1gl = ax.gridlines(crs=ccrs.PlateCarree(), draw_labels=True, linewidth=1, color='k', alpha=1,linestyle='--')#坐标轴设置gl.xformatter = LONGITUDE_FORMATTER ##坐标刻度转换为经纬度样式gl.yformatter = LATITUDE_FORMATTER#设置经纬度的显示，例如经度从70到135，间隔5显示gl.xlocator = mticker.FixedLocator(np.arange(70,135,5))gl.ylocator = mticker.FixedLocator(np.arange(15,55,5))

画比例尺和黑白边框

def drow_the_scale(y,x,text,length = 1.5,lw = 5):#画比例尺函数# y代表比例尺所在纬度# x代表比例尺开始的经度# text代表比例尺最后刻度值# length代表比例尺的长度，单位为多少个经度# lw代表比例尺的宽度step = length/5#计算步长，画五格#画黑白线五条plt.hlines(y=y,xmin=x,xmax=x + step,colors="black", ls="-", lw=lw)plt.hlines(y=y,xmin=x + step,xmax=x + step*2,colors="white", ls="-", lw=lw)plt.hlines(y=y,xmin=x + step*2,xmax=x + step*3,colors="black", ls="-", lw=lw)plt.hlines(y=y,xmin=x + step*3,xmax=x + step*4,colors="white", ls="-", lw=lw)plt.hlines(y=y,xmin=x + step*4,xmax=x + step*5,colors="black", ls="-", lw=lw)#画长刻度两个plt.vlines(x = x, ymin = y - (lw/100) *3, ymax = y + lw/100, colors="black", ls="-", lw=1)plt.vlines(x = x + length, ymin = y - (lw/100) *3, ymax = y + lw/100, colors="black", ls="-", lw=1)#画段刻度四个plt.vlines(x = x + step, ymin = y - (lw/100) *2, ymax = y + lw/100, colors="black", ls="-", lw=1)plt.vlines(x = x + step*2, ymin = y - (lw/100) *2, ymax = y + lw/100, colors="black", ls="-", lw=1)plt.vlines(x = x + step*3, ymin = y - (lw/100) *2, ymax = y + lw/100, colors="black", ls="-", lw=1)plt.vlines(x = x + step*4, ymin = y - (lw/100) *2, ymax = y + lw/100, colors="black", ls="-", lw=1)#写字，0，500，kmplt.text(x,y - (lw/100) *7,'0',horizontalalignment = 'center')plt.text(x + length,y - (lw/100) *7,text,horizontalalignment = 'center')plt.text(x + length/2,y + (lw/100)*2,'km',horizontalalignment = 'center')def drowscale(extent,scale_y,scale_x,scale_text,step = 5,lw = 10,scale_length = 1.5,scale_lw = 5):# 画地图黑白边框和比例尺# extent：表示四周经纬度[west, east, south, north]# scale_y,scale_x,scale_text：代表比例尺的位置，纬度，经度，刻度值# step：表示步长，一格代表几个经纬度# lw：代表边框宽度# scale_length：代表比例尺长度（单位为经度例如1.5个经度）# scale_lw：代表比例尺宽度for y in [extent[2],extent[3]] :#画上下两边框xmin = extent[0]while (xmin < extent[1]):plt.hlines(y=y,xmin=xmin,xmax=xmin+step,colors="white", ls="-", lw=lw)xmin = xmin+step*2xmin = extent[0]+stepwhile (xmin < extent[1]):plt.hlines(y=y,xmin=xmin,xmax=xmin+step,colors="black", ls="-", lw=lw)xmin = xmin+step*2for x in [extent[0],extent[1]] :#画左右两边狂ymin = extent[2]while (ymin < extent[3]):plt.vlines(x = x, ymin = ymin, ymax = ymin+step, colors="black", ls="-", lw=lw)ymin = ymin+step*2ymin = extent[2]+stepwhile (ymin < extent[3]):plt.vlines(x = x, ymin = ymin, ymax = ymin+step, colors="white", ls="-", lw=lw)ymin = ymin+step*2drow_the_scale(scale_y,scale_x,scale_text)#画比例尺

这里写了两个函数，一个套一个，其实就是在地图四周画黑白的线，然后在图片某个位置画黑白的线组成了一个比例尺，可以说有些取巧，以及相当的不规范，默认了1度代表111公里。
主要是作者实在是找不到cartopy画比例尺的函数是什么，basemap倒是有，但是不想用。如果哪位朋友知道的，请留言告诉我一下，感谢。

画散点信息

随便画了一些散点信息，给朋友们使用，总共五个函数，都是批量画散点的，给个经纬度列表就好了。上面的点是我随便标的。

def drowpentagram(ax,points,c = 'red',s=300):#画五角星   ax,points必带，c颜色，s大小for point in points:ax.scatter(point[0], point[1], marker = '*',c = c,s=s,transform=ccrs.PlateCarree())plt.text(point[0],point[1]+0.3,point[2],horizontalalignment = 'center')def drowcircle(ax,points,edgecolors = 'red',linewidths = 2,s=300):#画圈   ax,points必带，edgecolors颜色，s大小，linewidths线宽for point in points:ax.scatter(point[0], point[1], marker = 'o',edgecolors = edgecolors,c = 'none',linewidths = linewidths,s=s,transform=ccrs.PlateCarree())def drowfork(ax,points,c = 'blue',linewidths = 2,s=300):#画叉   ax,points必带，c颜色，s大小，linewidths线宽for point in points:ax.scatter(point[0], point[1], marker = 'x',c = c,linewidths = linewidths,s=s,transform=ccrs.PlateCarree())def drowbox(ax,points,edgecolors = 'blue',linewidths = 2,s=300):#画方   ax,points必带，edgecolors颜色，s大小，linewidths线宽for point in points:ax.scatter(point[0], point[1], marker = 's',edgecolors = edgecolors,c = 'none',linewidths = linewidths,s=s,transform=ccrs.PlateCarree())def drowtriangle(ax,points,edgecolors = 'blue',linewidths = 2,s=300):#画三角   ax,points必带，edgecolors颜色，s大小，linewidths线宽for point in points:ax.scatter(point[0], point[1], marker = '^',edgecolors = edgecolors,c = 'none',linewidths = linewidths,s=s,transform=ccrs.PlateCarree())

画图例

给出了一个图例函数，都是封装好的

def drowlegend(ax,x,y,text,step = 0.5):#画图例# x为图例左上角经度；# y为图例左上角纬度；# text为文字描述；# step为间距drowcircle(ax,((x,y),))#画红圈plt.text(x+step*1.5,y ,text[0],horizontalalignment = 'center')drowcircle(ax,((x,y - step),),edgecolors = 'green')#画绿圈plt.text(x+step*1.5,y- step ,text[1],horizontalalignment = 'center')drowfork(ax,((x,y - step*2),))#画叉plt.text(x+step*1.5,y- step*2 ,text[2],horizontalalignment = 'center')drowbox(ax,((x,y - step*3),))#画方plt.text(x+step*1.5,y- step*3 ,text[3],horizontalalignment = 'center')drowtriangle(ax,((x,y - step*4),))#画三角plt.text(x+step*1.5,y- step*4 ,text[4],horizontalalignment = 'center')

第四、全部代码

import matplotlib.pyplot as plt
import cartopy.crs as ccrs
import numpy as np
from cartopy.mpl.gridliner import LATITUDE_FORMATTER, LONGITUDE_FORMATTER
import matplotlib.ticker as mtickerdef drowpentagram(ax,points,c = 'red',s=300):#画五角星   ax,points必带，c颜色，s大小for point in points:ax.scatter(point[0], point[1], marker = '*',c = c,s=s,transform=ccrs.PlateCarree())plt.text(point[0],point[1]+0.3,point[2],horizontalalignment = 'center')def drowcircle(ax,points,edgecolors = 'red',linewidths = 2,s=300):#画圈   ax,points必带，edgecolors颜色，s大小，linewidths线宽for point in points:ax.scatter(point[0], point[1], marker = 'o',edgecolors = edgecolors,c = 'none',linewidths = linewidths,s=s,transform=ccrs.PlateCarree())def drowfork(ax,points,c = 'blue',linewidths = 2,s=300):#画叉   ax,points必带，c颜色，s大小，linewidths线宽for point in points:ax.scatter(point[0], point[1], marker = 'x',c = c,linewidths = linewidths,s=s,transform=ccrs.PlateCarree())def drowbox(ax,points,edgecolors = 'blue',linewidths = 2,s=300):#画方   ax,points必带，edgecolors颜色，s大小，linewidths线宽for point in points:ax.scatter(point[0], point[1], marker = 's',edgecolors = edgecolors,c = 'none',linewidths = linewidths,s=s,transform=ccrs.PlateCarree())def drowtriangle(ax,points,edgecolors = 'blue',linewidths = 2,s=300):#画三角   ax,points必带，edgecolors颜色，s大小，linewidths线宽for point in points:ax.scatter(point[0], point[1], marker = '^',edgecolors = edgecolors,c = 'none',linewidths = linewidths,s=s,transform=ccrs.PlateCarree())def drow_the_scale(y,x,text,length = 1.5,lw = 5):#画比例尺函数# y代表比例尺所在纬度# x代表比例尺开始的经度# text代表比例尺最后刻度值# length代表比例尺的长度，单位为多少个经度# lw代表比例尺的宽度step = length/5#计算步长，画五格#画黑白线五条plt.hlines(y=y,xmin=x,xmax=x + step,colors="black", ls="-", lw=lw)plt.hlines(y=y,xmin=x + step,xmax=x + step*2,colors="white", ls="-", lw=lw)plt.hlines(y=y,xmin=x + step*2,xmax=x + step*3,colors="black", ls="-", lw=lw)plt.hlines(y=y,xmin=x + step*3,xmax=x + step*4,colors="white", ls="-", lw=lw)plt.hlines(y=y,xmin=x + step*4,xmax=x + step*5,colors="black", ls="-", lw=lw)#画长刻度两个plt.vlines(x = x, ymin = y - (lw/100) *3, ymax = y + lw/100, colors="black", ls="-", lw=1)plt.vlines(x = x + length, ymin = y - (lw/100) *3, ymax = y + lw/100, colors="black", ls="-", lw=1)#画段刻度四个plt.vlines(x = x + step, ymin = y - (lw/100) *2, ymax = y + lw/100, colors="black", ls="-", lw=1)plt.vlines(x = x + step*2, ymin = y - (lw/100) *2, ymax = y + lw/100, colors="black", ls="-", lw=1)plt.vlines(x = x + step*3, ymin = y - (lw/100) *2, ymax = y + lw/100, colors="black", ls="-", lw=1)plt.vlines(x = x + step*4, ymin = y - (lw/100) *2, ymax = y + lw/100, colors="black", ls="-", lw=1)#写字，0，500，kmplt.text(x,y - (lw/100) *7,'0',horizontalalignment = 'center')plt.text(x + length,y - (lw/100) *7,text,horizontalalignment = 'center')plt.text(x + length/2,y + (lw/100)*2,'km',horizontalalignment = 'center')def drowscale(extent,scale_y,scale_x,scale_text,step = 5,lw = 10,scale_length = 1.5,scale_lw = 5):# 画地图黑白边框和比例尺# extent：表示四周经纬度[west, east, south, north]# scale_y,scale_x,scale_text：代表比例尺的位置，纬度，经度，刻度值# step：表示步长，一格代表几个经纬度# lw：代表边框宽度# scale_length：代表比例尺长度（单位为经度例如1.5个经度）# scale_lw：代表比例尺宽度for y in [extent[2],extent[3]] :#画上下两边框xmin = extent[0]while (xmin < extent[1]):plt.hlines(y=y,xmin=xmin,xmax=xmin+step,colors="white", ls="-", lw=lw)xmin = xmin+step*2xmin = extent[0]+stepwhile (xmin < extent[1]):plt.hlines(y=y,xmin=xmin,xmax=xmin+step,colors="black", ls="-", lw=lw)xmin = xmin+step*2for x in [extent[0],extent[1]] :#画左右两边狂ymin = extent[2]while (ymin < extent[3]):plt.vlines(x = x, ymin = ymin, ymax = ymin+step, colors="black", ls="-", lw=lw)ymin = ymin+step*2ymin = extent[2]+stepwhile (ymin < extent[3]):plt.vlines(x = x, ymin = ymin, ymax = ymin+step, colors="white", ls="-", lw=lw)ymin = ymin+step*2drow_the_scale(scale_y,scale_x,scale_text)#画比例尺def drowlegend(ax,x,y,text,step = 0.5):#画图例# x为图例左上角经度；# y为图例左上角纬度；# text为文字描述；# step为间距drowcircle(ax,((x,y),))#画红圈plt.text(x+step*1.5,y ,text[0],horizontalalignment = 'center')drowcircle(ax,((x,y - step),),edgecolors = 'green')#画绿圈plt.text(x+step*1.5,y- step ,text[1],horizontalalignment = 'center')drowfork(ax,((x,y - step*2),))#画叉plt.text(x+step*1.5,y- step*2 ,text[2],horizontalalignment = 'center')drowbox(ax,((x,y - step*3),))#画方plt.text(x+step*1.5,y- step*3 ,text[3],horizontalalignment = 'center')drowtriangle(ax,((x,y - step*4),))#画三角plt.text(x+step*1.5,y- step*4 ,text[4],horizontalalignment = 'center')pass#主函数
if __name__ == '__main__':points_pentagram = [(113.3, 23.23,'Guangzhou')]#五角星坐标和名称points_circle_red = [(116.1, 26.7),(117.1, 27.7)]#红圈坐标points_circle_green = [(115.1, 25.7),(118.1, 28.7)]#绿圈坐标points_fork = [(115.1, 26.7),(118.1, 29.7)]#叉坐标points_box = [(117.1, 26.7),(115.1, 27.7)]#方坐标points_triangle = [(118.1, 26.7),(114.1, 27.7)]#三角坐标#图例的文字描述text = ['大风','冰雹','龙卷','闪电','强降水']#地图四周经纬度west = 110east = 125south = 20north = 30#解决中文乱码问题plt.rcParams['font.sans-serif'] = ['SimHei']#画布设置，投影设置fig = plt.figure(figsize=(16,9.6))ax = fig.add_subplot(111,projection = ccrs.PlateCarree())#边界设置img_extent = [west, east, south, north]ax.set_extent(img_extent,crs = ccrs.PlateCarree())#浮雕地图导入fname = 'HYP_LR_SR_OB_DR.tif'ax.imshow(plt.imread(fname), origin='upper', transform=ccrs.PlateCarree(),extent=[-180, 180, -90, 90])#设置经纬度网格和标签，透明度改成1，就会出现网格 alpha=1gl = ax.gridlines(crs=ccrs.PlateCarree(), draw_labels=True, linewidth=1, color='k', alpha=0,linestyle='--')#坐标轴设置gl.xformatter = LONGITUDE_FORMATTER ##坐标刻度转换为经纬度样式gl.yformatter = LATITUDE_FORMATTER#设置经纬度的显示，例如经度从70到135，间隔5显示gl.xlocator = mticker.FixedLocator(np.arange(70,135,5))gl.ylocator = mticker.FixedLocator(np.arange(15,55,5))drowscale(img_extent,21,123.1,'500')#画比例尺drowpentagram(ax,points_pentagram)#画五角星drowcircle(ax,points_circle_red)#画红圈drowcircle(ax,points_circle_green,edgecolors = 'green')#画绿圈drowfork(ax,points_fork)#画叉drowbox(ax,points_box)#画方drowtriangle(ax,points_triangle)#画三角drowlegend(ax,123.1,24,text,step = 0.5)#画图例plt.show()

第五、求助

有朋友知道cartopy有自带的比例尺函数吗，翻了一下文档没找到，会的朋友留言帮忙一下，作者画的比例尺徒有其表，深究起来很不严谨。