美国边界线不会被添加到散布的美国地区的geom_map地图中 [英] US border line is not added to geom_map maps of dispersed US regions

问题描述

我在美国有分散的零件地图。这是在以下问题（包含数据链接）：

我试过geom_polygon（）和geom_maps（）。没有不同。这是什么原因，以及如何解决它？

非常感谢您的帮助！

解决方案

所以，问题在于预测的差异。美国地图是在UTM系统中，以米和东经和北纬为单位，但以长和经纬度命名。而美国地图处于经纬度协调系统。我在代码中的fortify行之前转换了形状，如下所示：

  library（ggplot2） 
 library（tidyverse）
 
 usa<  -  map_data（usa，）
 
 shape<  -  spTransform（shape，CRS（+ proj = longlat （形状，区域=名称）
 
 colnames（shape_map）<  -  c（long，lat，+ datum = WGS84））
 shape_map<  -  fortify order，hole，piece，region，group）
 
 prop.test<  -  proptest.result [which（proptest.result $ variable ==Upward N ），] 
 
 ggplot（）+ 
 geom_map（
 data = usa，map = usa，aes（long，lat，map_id = region），
 color =＃2b2b2b，fill =＃00000000
）+ 
 geom_map（
 data = shape_map，map = shape_map，
 aes（long，lat，map_id = region） 
）+ 
 geom_map（
 data = filter（prop.test，season ==DJF），
 map = shape_map，aes（fill = prop.mega，map_id = megaregion）
）+ 
 viridis :: scale_fill_viridis（direction = -1）+ 
 coord_map（polyconic）+ 
 ggth emes :: theme_map（）
  

这是结果图：

I have a map of dispersed parts in the Us. This is in the following question (that contains link to the data):

mapping by ggplot2 geom_polygon goes crazy after merging data

It was answered very well. Then I tried to add the US border line, therefore I added the geom_path to the answered code,but no result, it creates the same map just containing the dispersed areas.

library(ggplot2)
#library(tidyverse)
library(dplyr)
library(maps)
load("./data.rda")

usa <- map_data("usa")
shape_map <- tbl_df(fortify(shape, region="Name"))
colnames(shape_map) <- c("long", "lat", "order", "hole", "piece", "region", "group")


ggplot() +
    geom_path(data = usa, aes(long, lat, group=group))+
    geom_map(data=shape_map, map=shape_map, aes(long, lat, map_id=region)) +
    geom_map(
        data=filter(prop.test, season=="DJF"),
        map=shape_map, aes(fill=prop.mega, map_id=megaregion)
    )

I have tried geom_polygon() and geom_maps(). no difference. What's the reason, and how can it be solved?

Thank you so much for your help!

解决方案

So, the problem was the differences in the projections. The us map was in a UTM system, giving Easting and Northing in meters, but named as long and lat. while the US map was in a lat/lon coordinating system. I transformed the shape just before the fortify line in the code as below:

library(ggplot2)
library(tidyverse)

usa <- map_data("usa", )

shape <- spTransform(shape, CRS("+proj=longlat +datum=WGS84"))
shape_map <- fortify(shape, region="Name")

colnames(shape_map) <- c("long", "lat", "order", "hole", "piece", "region", "group")

prop.test <- proptest.result[which(proptest.result$variable=="Upward N"),]

ggplot() +
  geom_map(
    data=usa, map=usa, aes(long, lat, map_id=region),
    color="#2b2b2b", fill="#00000000"
  ) +
  geom_map(
    data=shape_map, map=shape_map, 
    aes(long, lat, map_id=region)
  ) +
  geom_map(
    data=filter(prop.test, season=="DJF"),
    map=shape_map, aes(fill=prop.mega, map_id=megaregion)
  ) +
  viridis::scale_fill_viridis(direction=-1) +
  coord_map("polyconic") +
  ggthemes::theme_map()

and this is the resulted map:

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