Get extent from index values in VRT text.
extent_vrt(x)url or file path to VRT file
(I can't understand XML tech so I hack the text as lines with strsplit)
#src <- "https://opentopography.s3.sdsc.edu/raster/NASADEM/NASADEM_be.vrt"
#src <- "https://opentopography.s3.sdsc.edu/raster/SRTM_GL1/SRTM_GL1_srtm.vrt"
#ex <- extent_vrt(src)
#op <- par(mar = rep(0, 4))
#plot(range(ex[,1:2]), range(ex[,3:4]), xlab = "", ylab = "", asp = "", type = "n")
#rect(ex[,1], ex[,3], ex[, 2], ex[,4])
#par(op)