---
title: "顶刊中的全球地图投影（五）-Orthographic投影Python实现"
source: https://www.zbhgis.com/blog/blog-20260306-1
author: zbhgis 浩瀚地学
created: 2026-03-06
tags: [科研, 科研地图, 地图投影]
---

> 本文来自浩瀚地学，规范页面（含代码高亮与图片灯箱）：https://www.zbhgis.com/blog/blog-20260306-1
# 顶刊中的全球地图投影（五）-Orthographic投影Python实现


# 前言

上一篇文章介绍了Spilhaus地图投影的补充，这篇将会进一步对Orthographic投影进行补充，帮助大家能够绘制出预期中的地图投影效果。

完整代码及数据均开源，获取方式见文末。

# Orthographic投影

## Orthographic投影是什么

正射投影（Orthographic projection）是一种方位透视投影（azimuthal perspective projection），其投影中心位于地球无限远处，导致所有投影射线相互平行，等效于平行光源从无穷远照射地球表面至切平面（通常为与球体相切的平面）。在现代，正射投影主要用于模拟卫星或太空视角的真实视觉效果、极地/区域专题展示。

参考：https://en.wikipedia.org/wiki/Orthographic_map_projection

以下图片来源：https://doi.org/10.1038/s41561-025-01894-y

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111605541.png)

## 不同的Orthographic投影

实现也比较简单，就是通过内置的 中心经度，中心纬度，方位角 三个参数调节。通过以下代码即可看到不同参数下的正射投影地图，适合极地或洲际或国家尺度研究。

orthographic.py

```Python
"""
-------------------------------------------------------------------------------
@Author         :  zbhgis
@Github         :  https://github.com/zbhgis
@Description    :  different views of orthographic projection
-------------------------------------------------------------------------------
"""

import matplotlib.pyplot as plt
import cartopy.crs as ccrs
import cartopy.feature as cfeature

# 设置投影名称与对应的投影
projections = [
    ("orthographic (0, 0, 0)", ccrs.Orthographic()),
    ("orthographic (100, 40, 0)", ccrs.Orthographic(100, 40, 0)),
    ("orthographic (-100, 40, 0)", ccrs.Orthographic(-100, 40, 0)),
    ("orthographic (100, 40, 45)", ccrs.Orthographic(100, 40, 45)),
    ("orthographic (100, 40, 90)", ccrs.Orthographic(100, 40, 90)),
    ("orthographic (0, 90, 0)", ccrs.Orthographic(0, 90, 0)),
    ("orthographic (0, 90, 180)", ccrs.Orthographic(0, 90, 180)),
]

# 每个投影一张图片
for proj_name, proj in projections:
    fig = plt.figure(figsize=(10, 10))
    ax = fig.add_subplot(1, 1, 1, projection=proj)
    ax.add_feature(cfeature.OCEAN, facecolor="#1f77b4", zorder=0)
    ax.add_feature(cfeature.LAND, facecolor="none", edgecolor="none", zorder=1)
    ax.coastlines(resolution="50m", color="black")
    ax.gridlines(draw_labels=True, linestyle="--")
    ax.set_title(proj_name, fontsize=16, pad=10)

    print(proj_name)
    plt.savefig(
        f"./fig_res/{proj_name}.png",
        dpi=100,
        bbox_inches="tight",
    )
    plt.close(fig)

```

打印结果

```Plain
orthographic (0, 0, 0)
orthographic (100, 40, 0)
orthographic (-100, 40, 0)
orthographic (100, 40, 45)
orthographic (100, 40, 90)
orthographic (0, 90, 0)
orthographic (0, 90, 90)
orthographic (0, 90, 180)
```

绘制结果

**Orthographic()**

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111606864.png)

**Orthographic(100, 40, 0)**

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111606648.png)

**Orthographic(-100, 40, 0)**

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg@main/blog/202603090850560.png)

**Orthographic(100, 40, 45)**

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111607159.png)

**Orthographic(100, 40, 90)**

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg@main/blog/202603090850510.png)

**Orthographic(0, 90, 0)**

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg@main/blog/202603090850904.png)

**Orthographic(0, 90, 180)**

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111607863.png)

## Orthographic投影范围设置

在绘制北半球地图时，热带区域并不是研究重点，需要突出极地或温带部分，因此绘制时会截取出某个纬度以北或以南的部分。

代码中以北极地区为例，设置了20°，40°，60°的范围。核心部分就是set_extent()至set_boundary()之间的代码。通过绘制一个圆形将所需的部分裁出即可。

orthographic2.py

```Python
"""
-------------------------------------------------------------------------------
@Author         :  zbhgis
@Github         :  https://github.com/zbhgis
@Description    :  different extents of orthographic projection
-------------------------------------------------------------------------------
"""

import matplotlib.pyplot as plt
import cartopy.crs as ccrs
import cartopy.feature as cfeature
import numpy as np
import matplotlib.path as mpath
import matplotlib.ticker as mticker

extents = [60, 40, 20]

# 每个投影一张图片
for extent in extents:
    proj_name, proj = ("orthographic (0, 90, 0)", ccrs.Orthographic(0, 90, 0))
    fig = plt.figure(figsize=(10, 10))
    ax = fig.add_subplot(1, 1, 1, projection=proj)

    ax.set_extent([-180, 180, extent, 90], crs=ccrs.PlateCarree())
    theta = np.linspace(0, 2 * np.pi, 100)
    center = (0.5, 0.5)
    radius = 0.5
    vertices = np.column_stack(
        [center[0] + radius * np.cos(theta), center[1] + radius * np.sin(theta)]
    )
    circle_path = mpath.Path(vertices)
    ax.set_boundary(circle_path, transform=ax.transAxes)

    ax.add_feature(cfeature.OCEAN, facecolor="#1f77b4", zorder=0)
    ax.add_feature(cfeature.LAND, facecolor="none", edgecolor="none", zorder=1)
    ax.coastlines(resolution="50m", color="black")
    gl = ax.gridlines(
        draw_labels=True,
        linestyle="--",
        alpha=0.5,
        linewidth=0.8,
    )
    gl.xlocator = mticker.MultipleLocator(20)
    gl.ylocator = mticker.MultipleLocator(20)
    ax.set_title(proj_name, fontsize=16, pad=10)

    print(proj_name)
    plt.savefig(
        f"./fig_res/{proj_name}_{extent}.png",
        dpi=100,
        bbox_inches="tight",
    )
    plt.close(fig)

```

打印结果

```Plain
orthographic (0, 90, 0)
orthographic (0, 90, 0)
orthographic (0, 90, 0)
```

绘制结果

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111608995.png)

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111608788.png)

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111608248.png)

# 写在最后

# 写在最后

完整代码及相关数据文件会在以下github仓库中开源，若有帮助欢迎点个star，不胜感激。

https://github.com/zbhgis/Projects

或者在微信公众号后台回复关键词“**代码获取**”即可获取百度网盘链接，找到对应名称的文件夹即可（百度网盘链接可能隔几天才会同步）。

![img](https://cdn.jsdelivr.net/gh/zbhgis/BlogImg2@main/blog/202610111608941.jpeg)

代码中使用了很多相对路径，建议获取的时候下载完整文件夹。

如有问题，欢迎添加个人微信交流。