orthogproj {globe} | R Documentation |
Orthogonal Projection
Description
Project points from the unit sphere onto a plane orthogonal to the viewing direction.
Usage
orthogproj(eye, top, loc)
Arguments
eye |
Viewpoint. A vector of length 3 (or a |
top |
Top point. A location which will be projected onto the |
loc |
Vector of length 3, or matrix with 3 columns,
or |
Details
This function is used to obtain orthogonal projections of points on the sphere, for use in plotting 3D views of the sphere.
Each point of loc
is expressed
in an orthonormal coordinate system determined by the
arguments eye
and top
. The coordinate system is
such that the third (z
) axis
passes through the eye of the viewer and the
centre of the sphere.
Value
A vector (or matrix) giving the transformed coordinates of each point, with the first two coordinates giving the orthogonal projection.
Author(s)
Adrian Baddeley and Tom Lawrence
See Also
Examples
orthogproj(place("newyorkcity"), place("northpole"), c(1,0,0))