stplanr (version 0.0.2)

bbox_scale: Scale a bounding box

Description

Takes a bounding box as an input and outputs a bounding box of a different size, centred at the same point.

Usage

bbox_scale(bb, scale_factor)

Arguments

bb

the bounding box or spatial object that will be used to crop shp

scale_factor

Number determining how much the bounding box will grow or shrink. If the value is 1, the output size will be the same as the input.

Examples

# dput(bbox(cents))
bb <- structure(c(-1.55080650299106, 53.8040984493515, -1.51186138683098,
53.828874094091), .Dim = c(2L, 2L), .Dimnames = list(c("coords.x1",
  "coords.x2"), c("min", "max")))
bb1 <- bbox_scale(bb, 1.05)
bb1
bb2 <- bbox_scale(bb, 0.75)
bb2
bb3 <- bbox_scale(bb, 0.1)
plot(x = bb1[1,], y = bb1[2,])
points(bb2[1,], bb2[2,])
points(bb3[1,], bb3[2,])
points(bb[1,], bb[2,], col = "red")
bbox_scale(bb, 0.75)