stplanr (version 0.2.4)

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

Numeric vector determining how much the bounding box will grow or shrink. Two numbers refer to extending the bounding box in x and y dimensions, respectively. If the value is 1, the output size will be the same as the input.

Examples

# NOT RUN {
bb <- matrix(c(-1.55, 53.80, -1.50, 53.83), nrow = 2)
bb1 <- bbox_scale(bb, scale_factor = 1.05)
bb2 <- bbox_scale(bb, scale_factor = c(2, 1.05))
bb3 <- bbox_scale(bb, 0.1)
plot(x = bb2[1,], y = bb2[2,])
points(bb1[1,], bb1[2,])
points(bb3[1,], bb3[2,])
points(bb[1,], bb[2,], col = "red")
# }