我如何绘制R中的地理参考数据集？ [英] How can I plot a georeferenced dataset in R?

问题描述

我有这个网格数据，我想在美国地图上绘制：

紧跟在行之后：

  all_data = read.table（windspeed.txt，header = TRUE）
  

使用以下命令反转行号：

pre $ max_row = max（all_data $ row）
all_data $ row = max_row-all_data $ row

这应该照顾它。

I have this gridded data that I want to plot on a US map: https://www.dropbox.com/s/9khcjgtv8ipo2u5/windspeed.txt?dl=0

library(ggplot2)
library(RColorBrewer)
library(rgdal)
library(sp)
library(maps)
options(max.print=5.5E5) 

all_data = read.table("windspeed.txt",header = TRUE)

res=0.01 #spacing of row and col coords pre-specified
origin_lat_lon=c(24.55, -130) 
all_data$row=(all_data$row)*res+origin_lat_lon[1] 
all_data$col=(all_data$col)*res+origin_lat_lon[2]
coords = cbind(all_data$col, all_data$row)
spdf = SpatialPointsDataFrame(coords, data=all_data) #sp = SpatialPoints(coords)
proj4string(spdf) <- CRS("+init=epsg:4269") 

df=as.data.frame(spdf)
myPalette <- colorRampPalette(rev(brewer.pal(10, "Spectral")))
usamap <- map_data("state")
ggplot(data=df,aes(x=col,y=row,color=m)) + 
  geom_polygon( data=usamap, aes(x=long, y=lat,group=group),colour="black", fill="white" )+
  geom_point()+
  scale_colour_gradientn(name = "Wind",colours = myPalette(10), limits=c(0,1))+
  xlab('Longitude')+
  ylab('Latitude')+
  theme_bw()+
  theme(line = element_blank())+
  theme(legend.position = c(.93,.20),panel.grid.major = element_line(colour = "#854440"))+
  ggsave("test.png",width=10, height=8,dpi=300)

But I am getting an inverted plot. Can you please help?

I previously got an answer for a similar dataset here: How to convert point data collected at grid interval to a georeferenced dataset in r?

解决方案

Your latitude values in this csv are reverted when compared to the dataset you previously had from the previous question you mentioned. All you have to do is to invert the row numbers in this new dataset:

Right after your line:

all_data = read.table("windspeed.txt",header = TRUE)

Invert the row numbers using:

max_row= max(all_data$row)
all_data$row=max_row-all_data$row 

That should take care of it.

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