[英]cannot plot negative longitude values in PlotOnStaticMap in R
我有:
> df1
lon lat grp
1 0.02310676 51.39729 0
2 -0.04666115 51.40614 0
3 0.09730595 51.38398 0
4 0.02458385 51.39580 1
並希望將其繪制在地圖上。
library(RgoogleMaps)
> center
[1] 51.389486 0.036657
mm=GetMap(center=center,zoom=10,maptype= "roadmap", destfile = "satellite.png")
PlotOnStaticMap(mm,lat=df1$lat,lon=df1$lon,pch=20,col=df1$grp, cex=2.3)
結果是3個正確放置的標記,丟失的標記是帶有負值的標記。 進一步檢查:
PlotOnStaticMap(mm,lat=51.40614,lon=0.04666115,pch=20,col=c('red','dark blue'), cex=2.3)
PlotOnStaticMap(mm,lat=51.40614,lon=-0.04666115,pch=20,col=c('red','dark blue'), cex=2.3)
非常感謝您提供有關如何在西半球包含點的任何建議!
在2018年6月 1日發布的RgoogleMaps 1.4.2版中似乎不再是這個問題:
library(RgoogleMaps)
## example data
df1 = data.frame(lon = c(0.02310676, -0.04666115, 0.09730595, 0.02458385)
, lat = c(51.39729, 51.40614, 51.38398, 51.39580)
, grp = c("0", "0", "0", "1"))
center = c(51.389486, 0.036657)
## get google map
dfl = tempfile(fileext = ".png")
mm = GetMap(center, zoom = 12, maptype = "roadmap", destfile = dfl)
## display map with points
par(pty = "s")
PlotOnStaticMap(mm, lat = df1$lat, lon = df1$lon, pch = 20, col = df1$grp, cex = 2.3)
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