将图例添加到使用dismo gmap R获取的Google地图

Question

[![require(raster)
require(dismo)

oc_go<-gmap(extent(c(10042219 ,19646634,-7110934,1881964)),type='terrain')
plot(oc_go)

...添加另一个图层

legend("bottom", legend = c(" 1", " 2"," 3"," 4"," 5"," 6"," 7"," 8"), fill = colvec, 
       cex = 0.7, inset = 0.9,xpd=T,horiz = T)

结果是

我想把传说放在绘图区的底部或外面。

像这样使用par（）

par(xpd = FALSE,mar=c(5.1, 4.1, 4.1, 4.5))
plot(oc_go)
par(xpd = TRUE)
legend(par()$usr[2] ,-1000000, legend = c(" 1", " 2"," 3"," 4"," 5"," 6"," 7"," 8"), fill = colvec, 
       cex = 0.7, inset = 0.9)

使用gmap（）下载的地图

似乎不能很好地工作。我还尝试覆盖情节区域，如答案3 Plot a legend outside of the plotting area in base graphics?

中所述