This method draws horizon graphs for each zone as
calculated with zonal from the directions defined by
xyLayer
Usage
## S4 method for signature 'RasterStackBrick,missing'
horizonplot(x, data = NULL,
dirXY = y, stat = 'mean', digits = 0,
origin = mean,
xlab = 'Time', ylab = 'direction',
colorkey = TRUE, colorkey.digits = 1,
scales=list(y = list(relation = "same")),
...)
Arguments
x
A RasterStackBrick object.
data
Not used.
dirXY
A direction as a function of the coordinates (see
xyLayer).
stat
a function to be applied to summarize the values by
zone. See zonal for details.
digits
An integer, number of digits for zonal.
origin
From the latticeExtra help page: "the baseline y
value for the first (positive) segment (i.e. the value at
which red changes to blue)." It can be: a number, used acrros
all panels, or a function (or a character defining a
function), evaluated with the values in each panel. The
default is the mean function.
xlab, ylab
Labels of the axis.
colorkey
If colorkey = TRUE a suitable color scale bar is
constructed using the values of origin and
horizonscale (see below). For additional information
see levelplot.
colorkey.digits
Digits for rounding values in colorkey
labels
scales
From the lattice::xyplot help page: "A list
determining how the x- and y-axes (tick marks and labels) are
drawn. The list contains parameters in name=value
form, and may also contain two other lists called x and
y of the same form. Components of x and
y affect the respective axes only, while those in
scales affect both. When parameters are specified in
both lists, the values in x or y are used." In
horizonplot the most interesting component is
relation, a character string that determines how axis
limits are calculated for each panel. Possible values are
"same" (default), "free" and "sliced".
"For <c3><a2><c2><80><c2><98>relation="same"<c3><a2><c2><80><c2><99>, the same limits,
usually large enough to encompass all the data, are used for
all the panels. For <c3><a2><c2><80><c2><98>relation="free"<c3><a2><c2><80><c2><99>, limits for each panel
is determined by just the points in that panel. Behavior for
<c3><a2><c2><80><c2><98>relation="sliced"<c3><a2><c2><80><c2><99> is similar, except that the length (max -
min) of the scales are constrained to remain the same across
panels."
...
Additional arguments for the horizonplot
function. horizonscale is the most interesting, being (from
the latticeExtra help page) "the scale of each color
segment. There are 3 positive segments and 3 negative segments. If
this is a given as a number then all panels will have comparable
distances, though not necessarily the same actual values (similar in
concept to <c3><a2><c2><80><c2><98>scales$relation = "sliced"<c3><a2><c2><80><c2><99>)". On the other hand,
col.regions is used to choose the color scale.
Details
(Extracted from the reference): "The horizon graph allows to
examine how a large number of items changed through time, to spot
extraordinary behaviors and predominant patterns, view each of the
items independently from the others when they wish, make comparisons
between the items, and view changes that occurred with enough
precision to determine if further examination is required."