R中的极地/地形图 | R中的极地

本文介绍了R中的极地/地形图的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在尝试制作与此类似的立体地图:

I am trying to produce a sterographic map similarly to this:

我要添加的内容是

坐标
纹线

这可以在基数R中或在ggplot2中使用.感谢您的帮助.

This can be in both base R or with ggplot2. Any help is appreciated.

到目前为止我的尝试

library(rgdal)
library(raster)

proj <- "+proj=stere +lat_0=90 +lat_ts=70 +lon_0=-45 +k=1 +x_0=0 +y_0=0 +a=6378273 +b=6356889.449 +units=m +no_defs"

data("wrld_simpl", package = "maptools")
wm <- crop(wrld_simpl, extent(-180, 180, 45, 90))
plot(wm)

wm <- spTransform(wm, CRSobj = CRS(proj))
plot(wm)

推荐答案

要复制的地图非常复杂，并且使其工作所需的所有细节似乎都超出了单个问题的范围.但是，这是您需要的大多数东西.

This is quite a complex map to reproduce, and all the details required to make it work seem beyond the scope of a single question. However, this is most of the stuff you require.

在ggplot中执行此操作更容易使用使用基本图形进行操作.但是，这是一个非常复杂的图形.

Doing this in ggplot is easier to do that using the base graphics. However, it is quite a complex graph to make.

我不得不使用一些技巧来使其正常工作.特别是，从 coord_map 生成的轴并没有在绘图的边缘结束，因此我不得不手动删除轴，然后使用 geom_text 和 geom_segment 下面的行.

I have had to use a few hacks to get it to work. In particular, the axes produced from coord_map did not end at the edge of the plot, so I had to manually delete the axes and then recreate them using the geom_text and geom_segment lines below.

library(rgdal)
library(raster)
library(ggplot2)

# Defines the x axes required
x_lines <- seq(-120,180, by = 60)

ggplot() +
  geom_polygon(data = wm_ggplot, aes(x = long, y = lat, group = group), fill = "grey", colour = "black", alpha = 0.8) +

  # Convert to polar coordinates
  coord_map("ortho", orientation = c(90, 0, 0)) +
  scale_y_continuous(breaks = seq(45, 90, by = 5), labels = NULL) +

  # Removes Axes and labels
  scale_x_continuous(breaks = NULL) +
  xlab("") +
  ylab("") +

  # Adds labels
  geom_text(aes(x = 180, y = seq(55, 85, by = 10), hjust = -0.2, label = paste0(seq(55, 85, by = 10), "°N"))) +
  geom_text(aes(x = x_lines, y = 39, label = c("120°W", "60°W", "0°", "60°E", "120°E", "180°W"))) +

  # Adds axes
  geom_hline(aes(yintercept = 45), size = 1)  +
  geom_segment(aes(y = 45, yend = 90, x = x_lines, xend = x_lines), linetype = "dashed") +

# Change theme to remove axes and ticks
theme(panel.background = element_blank(),
      panel.grid.major = element_line(size = 0.25, linetype = 'dashed',
                                      colour = "black"),
      axis.ticks=element_blank()) +
  labs(caption = "Designed by Mikey Harper")

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