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Jeff Newmiller

2020-May-18 15:26 UTC

[R] Classification of wind events

? source("../rollmean.R") ?

On May 18, 2020 4:11:52 AM PDT, Jim Lemon <drjimlemon at gmail.com>
wrote:>Hi Stefano,
>If I understand your request, this may also help, Uses the same data
>transformations as my previous email.
>
>png("SS_foehn.png")
>plot(mydf$data_POSIX,
> ifelse(mydf$main_dir %in%
c("WSW","SW"),mydf$max_speed,NA),
> type="b",main="Wind speed (WSW or SW) by time",
> xlab="Time of day",ylab="Wind speed km/h",
> col=rainbow(16)[as.numeric(mydf$main_dir)])
>abline(h=8,col="orange",lwd=2)
>source("../rollmean.R")
>rmws<-rollmean(mydf$max_speed,4)
>lines(mydf$data_POSIX,rmws,col="orange",lwd=2)
>legend("topleft","Rolling mean of 4 for wind speed",
> lty=1,lwd=2,col="orange")
>dev.off()
>
>Jim
-- 
Sent from my phone. Please excuse my brevity.

Jim Lemon

2020-May-19 01:02 UTC

head link

[R] Classification of wind events

Sorry, I should know better:

rollmean<-function(x,width=2) {
 lenx<-length(x)
 result<-rep(NA,lenx)
 for(i in 1:lenx) {
  chunk<-i:(i+width-1)
  if(i<width) chunk<-c(rep(1,width-i),1:i)
  if(i>(lenx-width)) chunk<-c(i:lenx,rep(lenx,i-(width-1)))
  result[i]<-mean(x[chunk])
 }
 return(result)
}

I forgot to replace this with:

library(zoo)
rollmean...

Jim

On Tue, May 19, 2020 at 1:26 AM Jeff Newmiller <jdnewmil at
dcn.davis.ca.us> wrote:>
> ? source("../rollmean.R") ?
>
> On May 18, 2020 4:11:52 AM PDT, Jim Lemon <drjimlemon at gmail.com>
wrote:
> >Hi Stefano,
> >If I understand your request, this may also help, Uses the same data
> >transformations as my previous email.
> >
> >png("SS_foehn.png")
> >plot(mydf$data_POSIX,
> > ifelse(mydf$main_dir %in%
c("WSW","SW"),mydf$max_speed,NA),
> > type="b",main="Wind speed (WSW or SW) by time",
> > xlab="Time of day",ylab="Wind speed km/h",
> > col=rainbow(16)[as.numeric(mydf$main_dir)])
> >abline(h=8,col="orange",lwd=2)
> >source("../rollmean.R")
> >rmws<-rollmean(mydf$max_speed,4)
> >lines(mydf$data_POSIX,rmws,col="orange",lwd=2)
> >legend("topleft","Rolling mean of 4 for wind
speed",
> > lty=1,lwd=2,col="orange")
> >dev.off()
> >
> >Jim
>
> --
> Sent from my phone. Please excuse my brevity.

Abby Spurdle

2020-May-19 10:58 UTC

head link

[R] Classification of wind events

I was impressed by Jim's effort.
So, I thought I'd try to produce an exploratory plot.

I've adapted some of his code.
The following script produces a heatmap for a cylindrical density estimate.
Bright areas are (mathematical) regions of high density.
However, the interpretation is complicated by the fact that the data
uses max wind speed rather than wind speed, per se.

I note your subject line, "Classification of wind events".
I'm not sure what sort of classification is possible.

Could there be some sort of lagged effect...?
(i.e. Could wind direction or speed at time t, be related to wind
direction or speed at time t-1, t-2, etc ...?).

------------------------------------------------------
library (barsurf)
library (probhat)
set.bs.theme ("blue")

g <- c ("WSW", "WSW", "SW", "SW",
"W", "WSW", "WSW", "WSW", "W",
"W",
    "SW", "WSW", "SSW", "S",
"SW", "SW", "WSW", "WNW", "W",
"WSW",
    "WSW", "SE", "SE", "SE",
"NW", "NNE", "ENE", "SE",
"NNW", "NW",
    "NW", "NW", "NW", "NW",
"NW", "NE", "NW", "NW", "NW",
"NW", "NW",
    "N", "WNW", "NW", "NNW",
"NNW", "NW", "NW", "NW",
"WNW", "ESE",
    "W", "WSW", "SW", "SW",
"SW", "WSW", "SW", "S", "S",
"SSW", "SW",
    "WSW", "WSW", "WSW", "WSW",
"WSW", "WSW", "WSW", "SW",
"WSW",
    "WSW", "WSW", "WSW", "SW",
"SW", "WSW", "WSW", "WSW",
"WSW",
    "WSW", "SW", "SW", "SW",
"SW", "SW", "SW", "SW", "SW",
"SW",
    "WSW", "WSW", "WSW", "WSW",
"SW", "SW", "SW", "SW", "WSW",
"SW",
    "SW", "SW", "SW", "SW",
"WSW", "SW", "SW", "W", "WSW",
"WSW",
    "SSW", "S", "WNW", "SW",
"W", "WSW", "WSW", "SE", "SE",
"SE",
    "NW", "NNE", "ENE", "SE",
"NNW", "NW", "NW", "NW", "NW",
"NW",
    "NW", "NE", "NW", "NW",
"NW", "NW", "NW", "N", "WNW",
"NW", "NNW",
    "NNW", "NW", "NW", "NW")
levels <- c("E", "ENE", "NE", "NNE",
"N", "NNW", "NW", "WNW",
    "W", "WSW", "SW", "SSW",
"S", "SSE", "SE", "ESE")
g <- factor (g, levels=levels)

r <- seq (0, 337.5, by=22.5)
x <- r [as.integer (g)]

y <- c (4.6, 4.6, 3.4, 3.1, 4.8, 4.2, 4.1, 4.5, 4.7, 4.3, 2.4, 2.3,
    2.2, 2.1, 2.9, 2.8, 1.8, 2.7, 4.3, 3.3, 2.3, 2.3, 3.2, 3.2, 2.9,
    2.3, 1.5, 1.8, 2.9, 2.4, 1.8, 2.4, 2.3, 2.6, 1.8, 2.3, 1.9, 2.2,
    2.8, 2.4, 1, 1.1, 1.6, 2.3, 2.5, 3.3, 3.4, 3.2, 4.5, 3.9, 3.1,
    2.4, 6, 7.8, 6.3, 7.8, 8.1, 6.1, 7.4, 9.5, 8.9, 9.1, 10.1, 10.5,
    11.1, 10.1, 10.9, 11.3, 13.4, 13.5, 12.8, 11.5, 13.1, 13.5, 11.1,
    10.5, 8.5, 10.1, 10.7, 13.6, 11.9, 14.9, 10.9, 10.9, 12.8, 12.1,
    9.1, 8.3, 8.8, 7.4, 8.4, 10.3, 10, 7, 8.5, 8.4, 8.6, 6.7, 7.3,
    6.2, 5.9, 5.9, 5.1, 5.8, 5.6, 6.5, 6.6, 11.7, 11.3, 8.7, 7.1,
    6.9, 4.3, 3.8, 4.3, 3.3, 2.3, 2.3, 3.2, 3.2, 2.9, 2.3, 1.5, 1.8,
    2.9, 2.4, 1.8, 2.4, 2.3, 2.6, 1.8, 2.3, 1.9, 2.2, 2.8, 2.4, 1,
    1.1, 1.6, 2.3, 2.5, 3.3, 3.4, 3.2, 4.5)

data.frame (g, x, y)

x2 <- c (x - 360, x, x + 360)
y2 <- rep (y, times=3)

fh <- pdfmv.cks (cbind (x2, y2), bw = c (240, 9.5) )

N <- 64
u <- seq (270, -90, length.out=N)
v <- seq (0, 15, length.out=N)
fv <- outer (u, v, function (x, y) fh (cbind (x, y) ) )

#not necessary for exploratory purposes
Fh <- cdfmv.cks (cbind (x2, y2), bw = c (240, 9.5) )
scaling.factor <- probmv (Fh, c (0, 0), c (360, max (y) ) )
fv <- fv / scaling.factor

#currently problems with descending x/y coords
#(to fix in near future)
#so set x-axis to [0, 1]
u2 <- seq (0, 1, length.out=N)

plot_cfield (u2, v, fv,
    axes = c (FALSE, TRUE),
    main="Wind Speed\n(Cylindrical Density Estimate)",
    xlab="direction", ylab="max wind speed",
    hcv=TRUE)
axis (1, c (0.05, 0.275, 0.5, 0.725, 0.95), c ("South",
"West",
"North", "East", "South"), FALSE)
abline (v=0.5, lty=2, col="white")

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R help - May 2020 - Classification of wind events

[R] Classification of wind events

[R] Classification of wind events

[R] Classification of wind events