readwind: readwind

In AustralianAntarcticDivision/raadtools: Tools for Synoptic Environmental Spatial Data

readwind

Description

Read wind

Usage

readwind(
  date,
  time.resolution = c("6hourly"),
  xylim = NULL,
  lon180 = TRUE,
  magonly = FALSE,
  dironly = FALSE,
  uonly = FALSE,
  vonly = FALSE,
  latest = TRUE,
  returnfiles = FALSE,
  ...,
  inputfiles = NULL
)

Arguments

date	date or dates of data to read,
time.resolution	time resoution data to read, daily or monthly
xylim	spatial extents to crop from source data, can be anything accepted by extent, see Details
lon180	defaults to TRUE, to "rotate" Pacific view 0, 360 data to Atlantic view -180, 180
magonly	return just the magnitude from the U and V components
dironly	return just the direction from the U and V, in degrees N=0, E=90, S=180, W=270
uonly	return just the horizontal component of velocity, U
vonly	return just the vertical component of velocity, V
latest	if TRUE (and date not supplied) return the latest time available
returnfiles	ignore options and just return the file names and dates
...	Arguments passed on to raadtools setNA mask out land values (only applies to monthly time.resolution)
inputfiles	input the files data base to speed up initialization

Details

Read wind data

The inputfiles argument may be used to speed up individual reads, see the examples. Note that this must then ignore the time.resolution argument, which is also set by windfiles - and no warning is given. If using this argument you must give the same time.resolution as was used to create the files data.frame.

Value

raster object

Examples

# Speed up individual read calls. 
ff <- windfiles(time.resolution = "6hourly")
t1 <- system.time({readwind(max(ff$date))})
t2 <- system.time({readwind(max(ff$date), inputfiles = ff)})
## Not run: 
 dts <- seq(as.Date("2000-01-01"), by = "1 days", length = 350)
 library(animation)
 ani.start(ani.width = 800, ani.height = 800)
 for (i in seq_along(dts)) {
    x <- readwind(dts[i]);
    if (i == 1L) crds <- coordinates(x[[1]])
    plot(sqrt(x[[1]]^2 + x[[2]]^2), xlim = c(40, 180), ylim = c(-90, -20));
x1 <- crds[,1]
y1 <- crds[,2]
x2 <- crds[,1] + values(x[[1]])/4
y2 <- crds[,2] + values(x[[2]])/4
    arrows(x1, y1, x2, y2, length = 0.06);
    plot(m, add = TRUE)
}
ani.stop()




## End(Not run)

AustralianAntarcticDivision/raadtools documentation built on Nov. 14, 2024, 4:27 p.m.