Alex Alex - 3 months ago 35
R Question

adding data on top of a 3D base map using R

I am trying to plot a 3D space time cube in R and I want to have a basemap.
I am using rgl library. I know how to plot my data using x, y and z, where z is the time variable. I have also managed to download a map that I want to use as reference from openstreetmap, using the library in R. However, I cannot find a way to plot my data on the map in a 3D environment. I found the following code in several sites and as an answer to a similar question:

map3d <- function(map, ...){
if(length(map$tiles)!=1){stop("multiple tiles not implemented") }
nx = map$tiles[[1]]$xres
ny = map$tiles[[1]]$yres
xmin = map$tiles[[1]]$bbox$p1[1]
xmax = map$tiles[[1]]$bbox$p2[1]
ymin = map$tiles[[1]]$bbox$p1[2]
ymax = map$tiles[[1]]$bbox$p2[2]
xc = seq(xmin,xmax,len=ny)
yc = seq(ymin,ymax,len=nx)
colours = matrix(map$tiles[[1]]$colorData,ny,nx)
m = matrix(0,ny,nx)
surface3d(xc,yc,m,col=colours, ...)
}


However, I cannot really understand how it works.
Here's my code so far:

library(rgl)
library(ggplot2)
library(openstreetmap)
map <- openmap(c(53.5,73.6),c(15.7,134.7),type= 'esri-topo')
plot3d(x,y,z, col= colour) # to plot my data
autoplot(map) # to plot the map. though this is 2D


Again, I know how to plot my data on a 2D map. Confused with the 3D.
Any hints and tips on how to do this?

Answer

One option is to use the newish 'show2d' function in 'rgl'.

library(rgl)
library(OpenStreetMap)
library(raster)

map <- openmap(c(53.5,73.6),c(15.7,134.7),type= 'esri-topo')

## fake up some xyz
xyz <- expand.grid(x = map$bbox$p1, 
               y = map$bbox$p2, 
               z = 1:4)

plot3d(xyz, col = "black") # to plot my data
show2d(raster::plotRGB(raster(map)), xyz = xyz)

This function captures the normal plot expression, writes it to PNG and then texture maps it onto a quad in the scene.

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