本文将介绍通过Python绘制地形图的方法,所需第三方Python相关模块包括 rasterio、geopandas、cartopy 等,可通过 pip 等方式安装。
1 示例代码
1.1 导入相关模块
import rasterio | |
import geopandas as gpd | |
import numpy as np | |
import cartopy.crs as ccrs | |
import matplotlib.pyplot as plt | |
from matplotlib.colors import LinearSegmentedColormap |
1.2 设置地图字体及字号
plt.rcParams["font.family"] = "Times New Roman" | |
plt.rcParams["font.size"] = 14 |
1.3 绘制地图
# 设置投影:墨卡托投影 | |
# cartopy 投影说明:https://www.cnblogs.com/youxiaogang/p/14247184.html | |
projection = ccrs.Mercator() | |
# 绘制地图 | |
fig, ax = plt.subplots(figsize=(20, 10), subplot_kw={'projection': projection}) | |
# 设置地图范围(数值参数为对应投影下的范围坐标) | |
ax.set_extent([13530000, 14630000, 4960000, 5850000], crs=projection) | |
# 读取矢量文件 | |
shp = gpd.read_file("Data/Jilin_Mercator.shp") | |
shp.plot(ax=ax, transform=projection, edgecolor="black", linewidth=1, facecolor="none") | |
# 创建自定义颜色映射 | |
colors = ["#369121", "#95C769", "#FFFFBF", "#E6865A", "#D14E30", "#BA1414"] | |
n_bins = 100 # 定义色带的颜色数量 | |
cmap_name = "green_brown" | |
cm = LinearSegmentedColormap.from_list(cmap_name, colors, N=n_bins) | |
# 读取地形栅格数据 | |
dataset = rasterio.open("Data/DEM_Jilin_Mercator.tif") | |
data = dataset.read(1) # 读取第一个波段的数据 | |
nodata_value = dataset.nodata # 获取NoData值 | |
# 创建掩膜,去除NoData区域 | |
data = np.ma.masked_where(data == nodata_value, data) | |
# 将地形栅格添加到地图中 | |
extent = [dataset.bounds.left, dataset.bounds.right, | |
dataset.bounds.bottom, dataset.bounds.top] | |
im = ax.imshow(data, origin="upper", extent=extent, | |
transform=projection, cmap=cm) | |
# 绘制网格线并添加标签 | |
gl = ax.gridlines(draw_labels=True, linestyle="--", color="#4F4F4F") | |
gl.xlocator = plt.FixedLocator(range(120, 135, 3)) | |
gl.ylocator = plt.FixedLocator(range(40, 50, 2)) | |
# 添加色带,设置色带的缩放比例为 0.4,主图和色带之间的间距为 0.1 | |
cbar = plt.colorbar(im, ax=ax, orientation="horizontal", shrink=0.4, pad=0.1) | |
cbar.set_label("Elevation (m)", labelpad=10) # 设置色带标签与色带的距离为 10 点 | |
cbar.ax.xaxis.set_label_position("top") # 设置色带标签位置 | |
plt.savefig("Pic.jpg", dpi=600) | |
plt.show() |
2 结果图展示
审核编辑:黄飞
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