R 在不规则网格上绘制等高线
我在R中翻阅了一页又一页的等高线图(包括许多关于stackoverflow的提示),但没有成功。这是我的等高线数据,包括添加卢旺达地图(数据包括14个经度、纬度和降雨值,如x、y和z): 以下是我在stackoverflow中尝试的代码:R 在不规则网格上绘制等高线,r,ggplot2,contour,R,Ggplot2,Contour,我在R中翻阅了一页又一页的等高线图(包括许多关于stackoverflow的提示),但没有成功。这是我的等高线数据,包括添加卢旺达地图(数据包括14个经度、纬度和降雨值,如x、y和z): 以下是我在stackoverflow中尝试的代码: datr <- read.table("Apr0130precip.txt",header=TRUE,sep=",") x <- datr$x y <- datr$y z <- datr$z require(akima) fld &
datr <- read.table("Apr0130precip.txt",header=TRUE,sep=",")
x <- datr$x
y <- datr$y
z <- datr$z
require(akima)
fld <- interp(x,y,z)
par(mar=c(5,5,1,1))
filled.contour(fld)
datr这里有一些使用base
R图形和ggplot
的不同可能性。生成简单等高线图和地图顶部的图
插值
基本ggplot
使用geom\u tile
和stat\u等高线的替代方案
ggplot
在从shapefile创建的地图上
#因为我没有你的地图对象,所以我喜欢这样:
#从中获取地图数据
# http://biogeo.ucdavis.edu/data/diva/adm/RWA_adm.zip
#将文件解压缩到名为“卢旺达”的文件夹
#使用rgdal::readOGR读取shapefile
#只需尝试三个形状文件中的第一个,这似乎很有效。
#“dsn”(数据源名称)是shapefile所在的文件夹
#“layer”是不带.shp扩展名的shapefile的名称。
图书馆(rgdal)
rwa
datr <- read.table("Apr0130precip.txt",header=TRUE,sep=",")
x <- datr$x
y <- datr$y
z <- datr$z
require(akima)
fld <- interp(x,y,z)
par(mar=c(5,5,1,1))
filled.contour(fld)
library(akima)
fld <- with(df, interp(x = Lon, y = Lat, z = Rain))
filled.contour(x = fld$x,
y = fld$y,
z = fld$z,
color.palette =
colorRampPalette(c("white", "blue")),
xlab = "Longitude",
ylab = "Latitude",
main = "Rwandan rainfall",
key.title = title(main = "Rain (mm)", cex.main = 1))
library(ggplot2)
library(reshape2)
# prepare data in long format
df <- melt(fld$z, na.rm = TRUE)
names(df) <- c("x", "y", "Rain")
df$Lon <- fld$x[df$x]
df$Lat <- fld$y[df$y]
ggplot(data = df, aes(x = Lon, y = Lat, z = Rain)) +
geom_tile(aes(fill = Rain)) +
stat_contour() +
ggtitle("Rwandan rainfall") +
xlab("Longitude") +
ylab("Latitude") +
scale_fill_continuous(name = "Rain (mm)",
low = "white", high = "blue") +
theme(plot.title = element_text(size = 25, face = "bold"),
legend.title = element_text(size = 15),
axis.text = element_text(size = 15),
axis.title.x = element_text(size = 20, vjust = -0.5),
axis.title.y = element_text(size = 20, vjust = 0.2),
legend.text = element_text(size = 10))
# grab a map. get_map creates a raster object
library(ggmap)
rwanda1 <- get_map(location = c(lon = 29.75, lat = -2),
zoom = 9,
maptype = "toner",
source = "stamen")
# alternative map
# rwanda2 <- get_map(location = c(lon = 29.75, lat = -2),
# zoom = 9,
# maptype = "terrain")
# plot the raster map
g1 <- ggmap(rwanda1)
g1
# plot map and rain data
# use coord_map with default mercator projection
g1 +
geom_tile(data = df, aes(x = Lon, y = Lat, z = Rain, fill = Rain), alpha = 0.8) +
stat_contour(data = df, aes(x = Lon, y = Lat, z = Rain)) +
ggtitle("Rwandan rainfall") +
xlab("Longitude") +
ylab("Latitude") +
scale_fill_continuous(name = "Rain (mm)",
low = "white", high = "blue") +
theme(plot.title = element_text(size = 25, face = "bold"),
legend.title = element_text(size = 15),
axis.text = element_text(size = 15),
axis.title.x = element_text(size = 20, vjust = -0.5),
axis.title.y = element_text(size = 20, vjust = 0.2),
legend.text = element_text(size = 10)) +
coord_map()
# Since I don't have your map object, I do like this instead:
# get map data from
# http://biogeo.ucdavis.edu/data/diva/adm/RWA_adm.zip
# unzip files to folder named "rwanda"
# read shapefile with rgdal::readOGR
# just try the first out of three shapefiles, which seemed to work.
# 'dsn' (data source name) is the folder where the shapefile is located
# 'layer' is the name of the shapefile without the .shp extension.
library(rgdal)
rwa <- readOGR(dsn = "rwanda", layer = "RWA_adm0")
class(rwa)
# [1] "SpatialPolygonsDataFrame"
# convert SpatialPolygonsDataFrame object to data.frame
rwa2 <- fortify(rwa)
class(rwa2)
# [1] "data.frame"
# plot map and raindata
ggplot() +
geom_polygon(data = rwa2, aes(x = long, y = lat, group = group),
colour = "black", size = 0.5, fill = "white") +
geom_tile(data = df, aes(x = Lon, y = Lat, z = Rain, fill = Rain), alpha = 0.8) +
stat_contour(data = df, aes(x = Lon, y = Lat, z = Rain)) +
ggtitle("Rwandan rainfall") +
xlab("Longitude") +
ylab("Latitude") +
scale_fill_continuous(name = "Rain (mm)",
low = "white", high = "blue") +
theme_bw() +
theme(plot.title = element_text(size = 25, face = "bold"),
legend.title = element_text(size = 15),
axis.text = element_text(size = 15),
axis.title.x = element_text(size = 20, vjust = -0.5),
axis.title.y = element_text(size = 20, vjust = 0.2),
legend.text = element_text(size = 10)) +
coord_map()