Transformation of coordinate systems
The functions transform a coordinate system into another coordinate system. Currently, essentially only from the earth system to cartesian.
RMtrafo is the internal basic function that also allows
to reduce vectors to their norm.
RMtrafo(phi, new) RFearth2cartesian(coord, units=NULL, system="cartesian", grid=FALSE) RFearth2dist(coord, units=NULL, system="cartesian", grid=FALSE, ...)
new |
integer or character. One of the values
or the corresponding Note that Default: |
phi |
optional submodel |
coord |
matrix or vector of earth coordinates |
units |
"km" or "miles"; if not given and
|
system |
integer or character. The coordinate system, e.g.
|
grid |
logical. Whether the given coordinates are considered to
be on a grid given by Default: |
... |
the optional arguments of |
The functions transform between different coordinate systems.
The function RMtrafo returns a matrix, in general. For
fixed column,
the results, applied to each row of the matrix, are returned.
The function RFearth2cartesian returns a matrix in
one-to-one correspondence with coord assuming that the
earth is an ellipsoid.
The function RFearth2dist calculates distances, cf.
dist, assuming that the
earth is an ellipsoid.
Important options are units and coordinate_system, see
RFoptions.
Note also that the zenit must be given explicitly for projection onto a plane. See the examples below.
Martin Schlather, schlather@math.uni-mannheim.de, https://www.wim.uni-mannheim.de/schlather/
For calculating the earth coordinates as ellipsoid:
data(weather) (coord <- weather[1:5, 3:4]) (z <- RFfctn(RMtrafo(new=RC_CARTESIAN_COORD), coord)) (z1 <- RFearth2cartesian(coord)) ## equals z z1 - z ## 0, i.e., z1 and t(z) are the same dist(z) (d <- RFearth2dist(coord)) d - dist(z) ## 0, i.e., d and dist(z) are the same ## projection onto planes RFoptions(zenit=c(-122, 47)) RFearth2cartesian(coord, system="gnomonic") RFearth2cartesian(coord, system="orthographic")
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