Mesh plot with raster / quadmesh, and types of meshes

discrete-vs-continuous-mesh.R

## latest needed for recent bug fix in triangles
## remotes::install_github("hypertidy/quadmesh")
 library(quadmesh)

r <- quadmesh::etopo
## volcano as a raster in 0:nr, 0:nc (just because it's small and familiar)
v <- raster::raster(volcano, xmn = 0, xmx = nrow(volcano), ymn = 0, ymx = ncol(volcano))
v <- raster::aggregate(v, fact = 2)
## 2D plot in any projection
mesh_plot(r, crs = "+proj=laea +lon_0=147 +lat_0=-42 +datum=WGS84", asp = 1)


## continuous mesh3d (quads, slightly nonsense in continous terms ...)
rgl::clear3d(); rgl::wire3d(quadmesh(v)); rgl::aspect3d(1, 1, 0.4); rgl::rglwidget()

## discrete mesh3d (quads constant height at cell value)
rgl::clear3d(); rgl::wire3d(dquadmesh(v)); rgl::aspect3d(1, 1, 0.4); rgl::rglwidget()

## continuous mesh3d (triangle corners at raster cell centre value)
rgl::clear3d();rgl::wire3d(triangmesh(v)); rgl::aspect3d(1, 1, 0.4);  rgl::rglwidget()

## discrete mesh3d (triangle constant height at the mean their corners)
rgl::clear3d();rgl::wire3d(dtriangmesh(v)); rgl::aspect3d(1, 1, 0.4);  rgl::rglwidget()