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Transform the coordinates of spline data

Source: R/transform.R
transform_coord.Rd

This function transforms the coordinates of spline data between Cartesian and polar coordinate systems. The origin x and y coordinates can be supplied by the user, or calculated automatically (see Details).

Usage

transform_coord(
  data,
  to = "polar",
  origin = NULL,
  fan_lines = c(10, 25),
  use_XY = FALSE
)

Arguments

data

A data set containing the spline coordinates (cartesian coordinates must be in columns named X and Y, polar coordinates in columns named angle and radius; these are the defaults in data imported with read_aaa()).

to

Which system to convert to, as a string, either "polar" or "cartesian" (the default is "polar").

origin

The coordinates of the origin as a vector of c(x, y) coordinates.

fan_lines

A numeric vector with two fan lines (the default is c(10, 25)).

use_XY

Whether to use the column names X and Y when converting to and from polar coordinates, rather than the default angle and radius (the default is FALSE. If TRUE, the columns X and Y are overwritten with the converted values. If converting to polar, X is the angle and Y the radius.

Value

An object of class tbl_df-class (a tibble).

Details

The transformation between the coordinate systems require the selection of an origin in Cartesian coordinates (x and y). The origin ideally corresponds to the virtual origin of the ultrasound waves from the probe. The origin coordinates can be supplied by the user as a vector with the origin argument, or they can be estimated automatically if origin = NULL (the default). The estimation is performed by get_origin (see that function documentation for details).