st_misc: Modify the geometry of a simple feature or bounding box...

In elipousson/overedge: Assorted Functions For Easier Map Making

Modify the geometry of a simple feature or bounding box object

Description

Support both bbox and sf objects as inputs.

Usage

st_scale_rotate(x, scale = 1, rotate = 0)

st_center(x, ext = TRUE, ...)

st_square(x, scale = 1, rotate = 0, inscribed = FALSE)

st_inscribed_square(x, scale = 1, rotate = 0)

st_circle(x, scale = 1, inscribed = FALSE, dTolerance = 0)

st_circumscribed_circle(x, scale = 1)

Arguments

x	A sf, sfc, or bbox object
scale	numeric; scale factor, Default: 1
rotate	numeric; degrees to rotate (-360 to 360), Default: 0
ext	If TRUE, st_center returns a list with the centroid as a sfc object, as an sf object (with lon and lat values), the original geometry (x), and the original crs. objects; defaults TRUE. If FALSE, return an sf object.
...	Additional parameters passed to sf::st_centroid() by st_center
inscribed	If TRUE, make circle or square inscribed within x, if FALSE, make it circumscribed.
dTolerance	numeric; tolerance parameter, specified for all or for each feature geometry. If you run st_simplify, the input data is specified with long-lat coordinates and sf_use_s2() returns TRUE, then the value of dTolerance must be specified in meters.

Details

• Scale or rotate a simple feature or bounding box object using affine transformations

• Get the center point for a sf object

• Get a circumscribed square or approximate inscribed square in a sf object

• Get a circumscribed circle or inscribed circle in a sf object

st_inscribed_square wraps sf::st_inscribed_circle() but limits the circle to 1 segment per quadrant (nQuadSegs = 1) and then rotates the resulting geometry 45 degrees to provide a (mostly) inscribed square. A different rotation value can be provided to change the orientation of the shape, e.g. rotate = -45 to return a diamond shape. st_square() wraps st_bbox_ext() with asp = 1.

See Also

• sf::geos_unary

Examples

nc <- read_sf_path(system.file("shape/nc.shp", package = "sf"))
nc <- st_transform_ext(nc, crs = 3857)

basemap <-
  ggplot2::ggplot() +
  ggplot2::geom_sf(data = nc) +
  ggplot2::theme_void()

basemap +
  layer_location_data(
    data = st_scale_rotate(nc, scale = 0.5, rotate = 15),
    fill = NA,
    color = "red"
    )

elipousson/overedge documentation built on Aug. 13, 2022, 7:41 p.m.