vectors giving the coordinates of the bivariate data
points to be binned. Alternatively a single plotting structure can
be specified: see xy.coords. NA's are
allowed and silently omitted.
xbins
the number of bins partitioning the range of xbnds.
shape
the shape = yheight/xwidth of the plotting regions.
xbnds, ybnds
horizontal and vertical limits of the binning
region in x or y units respectively; must be numeric vector of length 2.
xlab, ylab
optional character strings used as labels for
x and y. If NULL, sensible defaults are used.
IDs
logical indicating if the individual cell “IDs”
should be returned, see also below.
Details
Returns counts for non-empty cells only. The plot shape must be maintained for
hexagons to appear with equal sides. Some calculations are in single
precision.
Note that when plotting a hexbin object, the
grid package is used.
You must use its graphics (or those from package lattice if you
know how) to add to such plots.
Value
an S4 object of class "hexbin".
It has the following slots:
cell
vector of cell ids that can be mapped into the (x,y)
bin centers in data units.
count
vector of counts in the cells.
xcm
The x center of mass (average of x values) for the cell.
ycm
The y center of mass (average of y values) for the cell.
xbins
number of hexagons across the x axis. hexagon inner
diameter =diff(xbnds)/xbins in x units
shape
plot shape which is yheight(inches) / xwidth(inches)
xbnds
x coordinate bounds for binning and plotting
ybnds
y coordinate bounds for binning and plotting
dimen
The i and j limits of cnt treated as a matrix cnt[i,j]
n
number of (non NA) (x,y) points, i.e., sum(* @count).
ncells
number of cells, i.e., length(* @count), etc
call
the function call.
xlab, ylab
character strings to be used as axis labels.
cID
of class, "integer or NULL", only if IDs
was true, an integer vector of length n where
cID[i] is the cell number of the i-th original point
(x[i], y[i]). Consequently, the cell and count
slots are the same as the names and entries of
table(cID), see the example.
References
Carr, D. B. et al. (1987)
Scatterplot Matrix Techniques for Large N.
JASA83, 398, 424–436.