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Polar to cartesian coordinates conversion

polar2Projected.Rd

Computes projected coordinates (Easting, Northing, Altitude) from polar coordinates (Azimuth, Slope, Distance) and center position (Easting, Northing, Altitude). Magnetic declination and meridian convergence are optional parameters. In case distance is measured to the border of objects (e.g. trees), the diameter can be added to compute the coordinates of object center.

Usage

polar2Projected(
  x,
  y,
  z = 0,
  azimuth,
  dist,
  slope = 0,
  declination = 0,
  convergence = 0,
  diameter = 0
)

Arguments

x

vector. easting coordinates of centers in meter

y

vector. northing coordinates of centers in meter

z

vector. altitudes of centers in meters

azimuth

vector. azimuth values from centers in radian

dist

vector. distances between centers and objects in meter

slope

vector. slope values from centers in radian

declination

vector. magnetic declination values in radian

convergence

vector. meridian convergence values in radian

diameter

vector. diameters in meter (e.g. in case a radius should be added to the distance)

Value

A data.frame with easting, northing and altitude coordinates, and horizontal distance from centers to objects centers

See also

plot_tree_inventory for tree inventory display

Examples

# create data.frame of trees with polar coordinates and diameters
trees <- data.frame(
  x = rep(c(0, 10), each = 2),
  y = rep(c(0, 10), each = 2),
  z = rep(c(0, 2), each = 2),
  azimuth = rep(c(0, pi / 3)),
  dist = rep(c(2, 4)),
  slope = rep(c(0, pi / 6)),
  diameter.cm = c(15, 20, 25, 30)
)
trees
#>    x  y z  azimuth dist     slope diameter.cm
#> 1  0  0 0 0.000000    2 0.0000000          15
#> 2  0  0 0 1.047198    4 0.5235988          20
#> 3 10 10 2 0.000000    2 0.0000000          25
#> 4 10 10 2 1.047198    4 0.5235988          30

# compute projected coordinates
polar2Projected(trees$x, trees$y, trees$z, trees$azimuth, trees$dist,
  trees$slope,
  declination = 0.03, convergence = 0.02, trees$diameter.cm / 100
)
#>            x         y z        d
#> 1  0.1037068  2.072407 0 2.075000
#> 2  3.1718105  1.625558 2 3.564102
#> 3 10.1062057 12.122344 2 2.125000
#> 4 13.2163071 11.648362 4 3.614102