BGM examples

Michael D. Sumner

2020-04-12

Available BGM examples

The bgmfiles package contains several real-world example BGM files.

Obtain every available BGM file and plot in native coordinates.

library(rbgm)

## Loading required package: raster

## Loading required package: sp

library(bgmfiles)

## turn +proj into line separated text
breakproj <- function(x) {
  paste(strsplit(x, " ")[[1]], collapse = "\n")
}
files <- bgmfiles()
for (i in seq_along(files)) {
  bgm <- bgmfile(files[i])
  boxes <- boxSpatial(bgm)
  plot(boxes, col = ifelse(boxes$boundary, "#88888880", sample(rainbow(nrow(boxes), alpha = 0.5))))
  op <- par(xpd = NA)
  par(op)
  title(basename(files[i]), cex = 0.8)
  mtext(breakproj(proj4string(boxes)), cex = 0.75, side = 2, las = 1, adj = 0, line = 2, at = par("usr")[3], xpd = NA)

}

## /Users/runner/runners/2.168.0/work/_temp/Library/bgmfiles/extdata/bgm/ams71.bgm 
## file declares 187 faces but contains data for 193 faces
## 
##  ... returning all 193 faces

Make one interactive map with all (code not run here to avoid dependencies).

library(rbgm)
library(bgmfiles)
library(mapview)


mp <- mapview()  ## empty map view

fs <- bgmfiles::bgmfiles()  ## paths of all files collected
cols <- rainbow(length(fs), alpha = 0.2)
## read in all boxes, convert to SpatialPolygonsDataFrame, and add to the map view
for (i in seq_along(fs)) {
  mp <- mp + mapview(boxSpatial(bgmfile(fs[i])), color = cols[i], alpha = 0.3, layer.name = basename(fs[i]))
}

## view the mapview
mp