| image.seas.sum {seas} | R Documentation |
Graphically display a seasonal sum object, as well as the method of solution of the median/quantile “normal”
## S3 method for class 'seas.sum':
image(x, var, norm = "days", start=1, rep=0, zlim, alim,
palette = colorRampPalette(c("white","blue"))(64),
year.filter, power, contour=TRUE, show.median,
main, ...)
x |
a seas.sum object |
var |
the desired variable to show, otherwise will use the prime
variable, defined in x |
norm |
variable to normalize by, usually "days", to
produce unit/day |
start |
starting bin number; e.g., for monthly sums, if
start=5, the plot will start on "May" at the left-hand side;
show.median cannot be produced if start is greater
than one, since the annual sums (row-wise) would be a mix of
different annums |
rep |
repetition of the bins (columns) |
zlim |
range of normalized values displayed; this can be either a
single number for the maximum (minimum set to zero), or a
c(min,max) range with a defined minimum |
alim |
if show.median, this is the range for the annual
sums; this can either be a singe number for the maximum (minimum set
to zero, or a c(min,max) range with a defined minimum |
palette |
colours for image; the use of
colorRampPalette is recommended |
year.filter |
specifies the annual seasons to display |
power |
this transforms the normalized values for the colours to
a power (^), such as 0.5 for square-root
(sqrt), or others; this can help improve the contrast
in the display of data, but the quantities displayed in the
colour-bar and contours remain untransformed |
contour |
logical; show contours in lower left-hand plot |
show.median |
logical; show how the median calculation is
achieved graphically (computationally it is done using a secant
method); see seas.norm for more information on this
method; this can only be shown if the annums (rows) are complete, so
start must be 1, and rep must be 0 (otherwise the
row-wise sums would not be the annual sums) |
main |
main title for plot, otherwise it will automatically be
generated; NA suppresses a title, and automatically adjusts
the device margins |
... |
ignored |
This is a graphical representation of a seas.sum object,
and is far more informative than a traditional precipitation
“normal” (i.e., precip.norm or
precip.norm)
If norm = "days" and show.median = TRUE (default), the
seasonal sums appear in right-hand frames. Horizontal and vertical
lines indicate a ‘normal’ from the image, whereby the sum of
the quantile is equal to the median of the annual amount. This
numerical solution is found using seas.norm.
M.W. Toews
See SeasOpts to modify other aspects of the plot
data(mscdata)
dat <- mksub(mscdata, id=1108447)
dat.ss <- seas.sum(dat, width="mon")
image(dat.ss)
image(dat.ss,contour=FALSE)
image(dat.ss,norm="active",start=6,rep=5)
# different start day (not Jan 1st)
dat2.ss <- seas.sum(dat,start.day=as.Date("2001-08-01"))
image(dat2.ss)
image(dat2.ss,power=2)
image(dat2.ss,palette=rainbow(64),main=NA) # no title
image(dat2.ss,palette=colorRampPalette(c("white","darkgreen"))(16))
image(dat2.ss,"snow")
image(dat2.ss,"snow",power=0.5)
# growing degree days for 10 degC
dat$gdd10 <- dat$t_mean - 10
dat$gdd10[dat$gdd10<0] <- 0
attr(dat$gdd10,"long.name") <- "growing degree days"
dat3.ss <- seas.sum(dat,var="gdd10")
image(dat3.ss,"gdd10",palette=colorRampPalette(c("white","red"))(64))