从地图中删除边距

Question

我似乎无法从空间对象的图中移除边距.在这种情况下,发布到其他类型图表的解决方案似乎不起作用.Par mai和oma参数也失败了.非常感谢您的建议.

library(maptools)
data(wrld_simpl)
bbox = cbind(c(179,179,-179,-179,179), c(89,-89,-89,89,89))

png('test.png', width=1000, height=500)
par(mai=c(0,0,0,0), oma=c(0,0,0,0))
plot(wrld_simpl, col='grey', bg='white', border=NA)
lines(bbox, col='red', lwd=3)
dev.off()
browseURL('test.png')

红色边界框应该在图形输出边框内部绘制.

Answer 1

这将绘制没有边距的地图(虽然我仍然不知道这是否是你想要的).

require(maptools)
data(wrld_simpl)

# set up the output file
png('test.png', width=1200, height = 600, res = 300)

# define the plot and margins
par(ann = FALSE,
    bg = "white",
    bty = "n",
    mai = c(0,0,0,0),
    mgp = c(0, 0, 0),
    oma = c(0,0,0,0),
    omd = c(0,1,0,1),
    omi = c(0,0,0,0),
    usr = c(-180, 180, -90, 90),
    pin = c(4,2),
    plt = c(0,1,0,1),
    pty = "m",
    xaxs = 'i',
    xaxt = 'n',
    xpd = FALSE,
    yaxs = 'i',
    yaxt = 'n')
# plot the world map
plot(wrld_simpl,
     col='grey',
     bg='white',
     border=NA,
     ann=FALSE,
     axes = FALSE)
# plot points at extremes
par(new = TRUE)

plot(c(0,0,-180,180),c(90,-90,0,0), type = "p", col = "red",pch="+", cex=0.5)

dev.off()
browseURL('test.png')