do_projection: Project points onto globe
Description
Project points in x onto the globe and filter x to points within the current field of view.
Usage
do_projection(x, lon = 0, lat = 0, n.period = 360, n.frames = n.period)
Arguments
lon
starting longitude for rotation sequence or vector of arbitrary longitude sequence.
lat
fixed latitude or vector of arbitrary latitude sequence.
n.period
intended length of the period.
n.frames
intended number of frames in animation.
Value
returns a data frame containing visible points on the globe.
Details
do_projection projects the coordinates in x onto the globe and filters x to the subset of rows
containing data which are visible given the current field of view.
The field of view is defined by the centroid focus latitude and longitude pair in the sequence of latitudes and longitudes whose index
corresponds to the frame ID in x.