stplanr (version 0.2.4)

geo_bb: Flexible function to generate bounding boxes

Description

Takes a geographic object or bounding box as an input and outputs a bounding box, represented as a bounding box, corner points or rectangular polygon.

Usage

geo_bb(shp, scale_factor = 1, distance = 0, output = c("polygon",
  "points", "bb"))

Arguments

shp

Spatial object (from sf or sp packages)

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.

distance

Distance in metres to extend the bounding box by

output

Type of object returned (polygon by default)

See Also

bb_scale

Examples

# NOT RUN {
plot(geo_bb(routes_fast, distance = 100), col = "red")
plot(geo_bb(routes_fast, scale_factor = 0.8), col = "green", add = TRUE)
plot(geo_bb(sp::bbox(routes_fast)), add = TRUE) # works on bb also
plot(geo_bb(routes_fast, output = "points"), add = TRUE)
# Simple features implementation:
bb_sf1 <- geo_bb(routes_fast_sf, scale_factor = c(2, 1.5))
bb_sf2 <- geo_bb(routes_fast_sf, c(2, 1.5), distance = 100)
plot(bb_sf1)
plot(bb_sf2, add = TRUE)
plot(routes_fast, add = TRUE)
plot(geo_bb(routes_fast_sf, output = "points"), add = TRUE)
bb_matrix <- geo_bb(routes_fast, scale_factor = c(2, 1.1), output = "bb")
if(require(tmap)) { # as input into tmap plot
tm_shape(shp = routes_fast_sf[2:5, ], bbox = bb_matrix) +
  tm_lines()
}
# }