Does the following do what you want (or at least move in that direction)? u <- array(NA,c(5,8)) t <- seq(from=0.5, to=0.11,length=15) t2 <- seq(from=(-0.7),to=(-0.1),length=25) u[1:15] <- t u[16:40] <- t2 v <- array(NA,c(5,8)) y <- seq(from=(-0.9), to=(-0.01),length=40) v[1:40] <- y
library(TeachingDemos) library(maps) map('state',col='grey') lats <- seq( 27.5, 48.7, length=5 ) longs <- seq( -123, -73, length=8 ) x <- longs[ col(u) ] y <- lats[ row(u) ] speed <- sqrt( u*u+v*v ) dir <- atan2(v,u) my.symbols(x,y,ms.arrows, angle=dir, r=speed, add=TRUE, length=.05) Hope this helps, -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Jenny Barnes > Sent: Tuesday, April 29, 2008 6:26 AM > To: Jim Lemon > Cc: r-help@r-project.org > Subject: Re: [R] How to plot wind direction and strength field > > Thanks Jim - here is some data: > > u <- array(NA,c(5,8)) > t <- seq(from=0.5, to=0.11,length=15) > t2 <- seq(from=(-0.7),to=(-0.1),length=25) > u[1:15] <- t > u[16:40] <- t2 > v <- array(NA,c(5,8)) > y <- seq(from=(-0.9), to=(-0.01),length=40) v[1:40] <- y > > I've made up the data but it's similar magnitude and the > longitude direction is u and latitude direction is v as in > the real data. > > I really appreciate your help! > > Jenny > > On Tue, 29 Apr 2008, Jim Lemon wrote: > > > Jenny Barnes wrote: > >> Hi Jim, > >> > >> I would like to plot something like figure 2 on this webpage: > >> http://www.cnrfc.noaa.gov/storm_summaries/jan1997storms.php > >> > >> My data is very large - covering the whole globe at 2.5deg > resolution > >> so > >> longitude=144 girds, latitude=73 grids and time=32 years - hard to > >> give you that data......Would it help to give you a couple of grid > >> squares worth of data for one year? > >> > > Okay, Figures 2 and 3 look like 5 degree squares, and given > a larger > > plot, > > 2.5 degree should be okay. Do you want curved arrows? That > would take > > some programming as the standard arrows are straight. Also, > the arrows > > in the figures all seem to be the same length. I can make > the lengths > > proportional to wind speed. Yes, some data would be helpful, as > > getting the right plot usually involves trying out real > data. Doesn't > > matter if it's faked as long as it has the same format and > similar numbers to the real thing. > > > > Jim > > > > > > > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.