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我已經使用ggplot代碼(簡化版本的代碼)從我在中國的研究地點的柵格對象(來自worldclim的高程數據)創建了一個高程圖。相關的柵格對象已從worldclim.org下載並使用柵格包轉換爲data.frame。這是用於此圖的數據的link。從ggplot地圖上的osmar對象繪製道路
# load library
library("tidyverse")
load(file = "gongga.RData")
ggplot() +
geom_raster(data = gongga, aes(x=x, y=y, fill = elev)) +
coord_equal() +
scale_fill_gradient(name = "Elevation", low = "grey0", high = "grey100") +
scale_x_continuous(expand = c(0,0)) +
scale_y_continuous(expand = c(0,0)) +
theme(aspect.ratio=1/1, text = element_text(size=15))
爲清楚起見,我想道路添加到地圖中。我遇到了從Openstreetmap中提取道路的osmar包。
使用here中的代碼,我提取了正確部分的道路,但我不知道如何將它們繪製到我現有的ggplot中。
# EXTRACT ROADS FROM OPENSTREETMAP AND PLOT THEM WITH RANDOM POINTS
# Load libraries
library('osmar')
library('geosphere')
# Define the spatial extend of the OSM data we want to retrieve
moxi.box <- center_bbox(center_lon = 102.025, center_lat = 29.875,
width = 10000, height = 10000)
# Download all osm data inside this area
api <- osmsource_api()
moxi <- get_osm(moxi.box, source = api)
# Find highways
ways <- find(moxi, way(tags(k == "highway")))
ways <- find_down(moxi, way(ways))
ways <- subset(moxi, ids = ways)
# SpatialLinesDataFrame object
hw_lines <- as_sp(ways, "lines")
# Plot points
plot(hw_lines, xlab = "Lon", ylab = "Lat")
box()
該對象是否需要任何轉換將其繪製在ggplot中? 還是有更好的解決方案比奧斯馬包爲我的目的?
謝謝,理查德。完美的工作。 – Aud