geometr (version 0.2.5)

gs_point: Create a point geom

Description

Create a point geometry (of class geom) either by specifying anchor values or by sketching it.

Usage

gs_point(anchor = NULL, window = NULL, vertices = 1, sketch = NULL, ...)

Arguments

anchor

[geom(1)|data.frame(1)] Object to derive the geom from. It must include column names x, y and optionally a custom fid.

window

[data.frame(1)] in case the reference window deviates from the bounding box of anchor (minimum and maximum values), specify this here.

vertices

[integer(1)] number of vertices.

sketch

[raster(1)] raster object that serves as template to sketch polygons.

...

[various] graphical parameters to gt_locate, in case points are sketched; see gpar

Value

An invisible geom.

Details

The arguments anchor and sketch indicate how the line is created:

• if anchor is set, the line is created parametrically from the given objects' points,

• if an object is set in sketch, this is used to create the geom interactively, by clicking into the plot.

See Also

Other geometry shapes: gs_line(), gs_polygon(), gs_random()

Examples

# NOT RUN {
# 1. create points programmatically
coords <- data.frame(x = c(40, 70, 70, 50),
                     y = c(40, 40, 60, 70))

# if no window is set, the bounding box will be set as window
(aGeom <- gs_point(anchor = coords))

# the vertices are plottet relative to the window
library(magrittr)
window <- data.frame(x = c(0, 80),
                     y = c(0, 80))
gs_point(anchor = coords, window = window) %>%
  visualise(linecol = "green")

# when a geom is used in 'anchor', its properties are passed on
aGeom <- setWindow(x = aGeom, to = window)
gs_point(anchor = aGeom) %>%
  visualise(geom = .)
# }
# NOT RUN {
# 2. sketch two points by clicking into a template
gs_point(sketch = gtRasters$continuous, vertices = 2) %>%
  visualise(geom = ., linecol = "green", pointsymbol = 5, new = FALSE)
# }