Zakky
July 18, 2019, 7:11am
1
Hello House
I have a time series data set for time(m=1-3hrs) of two variables (uwnd and vwnd). For each iteration in the loop, I want the result to be stored in each column. nrow=95200, ncol =1, time =3.
Below please find my script as its not giving the desired results :
result <- data.frame( ) # initialize vector to store results, length = ncol(mydata)
for (m in 1:3) # for(m in 1:ncol(dname1)).
wsp_slice_10 <- matrix(nrow = nlon, ncol = nlat)
}
lonlat <- expand.grid(lon, lat)
wsp_slice_10.df01 <- data.frame(cbind(lonlat, wsp_slice_10.vec))
head(wsp_slice_10.df01)
length(wsp_slice_10.vec)
answ <- (wsp_slice_10.df01[3]) # change to assignment
wsp_answ <- answ
output =result
Zakky
July 18, 2019, 12:27pm
3
Hello,
I have a climate data set "dname" comprising of two variables (uwnd and vwnd) for time period of 1-3hours. The dataset is on a regular long and lat points (Nx= 280 , Ny= 340). I need to calculate the wind speed values for the three time periods (iterations, m=3) using the below equation:
wsp = (((uwnd)^2) + ((vwnd)^2))^0.5
Also, I want the results to be stored in matrix format "Nx*Ny by time (95200 by 3)". Please note that dname 1 and dname2 are the selected uwnd and vwnd data from dname.nc for time period of 3hours, respectively.
Below please find my written code for review
wsp_answ <- matrix(nrow = (nlon* nlat), ncol = 3)
wsp_answ <- data.frame(wsp_answ)
for (m in 1:3)
{
uwnd_10.slice <- dname1[, , m]
vwnd_10.slice <- dname2[, , m]
for(i in 1:dim(uwnd_10.slice)[1]) {
for(j in 1:dim(vwnd_10.slice)[2]) {
wsp_slice_10[i,j] <- (((uwnd_10.slice[i])^2) + ((vwnd_10.slice[j])^2))^0.5
}
}
lonlat <- expand.grid(lon, lat)
wsp_slice_10.vec <- as.vector(wsp_slice_10)
wsp_slice_10.df01 <- data.frame(cbind(lonlat, wsp_slice_10.vec))
head(wsp_slice_10.df01)
answ <- (wsp_slice_10.df01[3]) # change to assignment
wsp_answ <- answ[]
}
The results for the last iteration m=3 is only produced on a matrix of 95200 by 1 instead of m =1,2 and 3 on a matrix of 95200*3 . Useful suggestions would be appreciated.
Zakky
July 18, 2019, 5:11pm
5
Sampled datasets for three iterations (m=1:3), nlon = 11 , nlat = 3 .
time = m = 1
time = m = 2
time = m = 3
results should look similar to the following format
Date. wsp_m1. wsp_m2. wsp_m3
2008/12/31 2.9. 3.4. 5.4
wsp_answ <- matrix(nrow = (nlon* nlat), ncol = m=3)
for (m in 1:3)
{
uwnd_10.slice <- uwnd[, , m]
vwnd_10.slice <- vwnd[, , m]
for(i in 1:dim(uwnd_10.slice)) {
for(j in 1:dim(vwnd_10.slice)) {
wsp_slice_10[i,j] <- (((uwnd_10.slice[i])^2) + ((vwnd_10.slice[j])^2))^0.5
}
}
lonlat <- expand.grid(lon, lat)
wsp_slice_10.vec <- as.vector(wsp_slice_10)
wsp_slice_10.df01 <- data.frame(cbind(lonlat, wsp_slice_10.vec))
head(wsp_slice_10.df01)
answ <- (wsp_slice_10.df01[3]) # change to assignment
wsp_answ <- answ[]
}
Hi! Sorry for late reply, but I didn't have any free time the last 2-3 days.
Maybe you're looking for something like this?
data_at_time_1 <- read.table(text = 'Date lon lat uwnd vwnd
2008/12/31 -67.25 -55.75 8.2 -2.6
2009/01/01 -69.75 -55.75 -7.9 1.2
2009/01/02 -69.25 -55.75 1.4 4.9
2009/01/03 -68.75 -55.75 -7.8 2.3
2009/01/04 -68.25 -55.25 8.9 -1.2
2009/01/05 -67.75 -55.25 -9.1 0.8
2009/01/06 -67.25 -55.25 3.0 1.3
2009/01/07 -71.75 -54.75 -1.8 -1.6
2009/01/08 -70.75 -54.75 8.7 0.2
2009/01/09 -70.25 -54.75 -3.9 1.4
2009/01/10 -69.75 -54.75 -2.8 3.4',
header = TRUE)
data_at_time_2 <- read.table(text = 'Date lon lat uwnd vwnd
2008/12/31 -67.25 -55.75 2.2 6.7
2009/01/01 -69.75 -55.75 9.1 -0.6
2009/01/02 -69.25 -55.75 5.9 1.3
2009/01/03 -68.75 -55.75 8.8 -2.0
2009/01/04 -68.25 -55.25 3.9 1.8
2009/01/05 -67.75 -55.25 1.4 -4.2
2009/01/06 -67.25 -55.25 4.2 1.6
2009/01/07 -71.75 -54.75 6.8 -2.4
2009/01/08 -70.75 -54.75 9.8 -0.6
2009/01/09 -70.25 -54.75 3.9 2.6
2009/01/10 -69.75 -54.75 5.2 -1.8',
header = TRUE)
data_at_time_3 <- read.table(text = 'Date lon lat uwnd vwnd
2008/12/31 -67.25 -55.75 -2.2 3.4
2009/01/01 -69.75 -55.75 1.9 6.7
2009/01/02 -69.25 -55.75 -5.4 2.9
2009/01/03 -68.75 -55.75 3.8 -4.1
2009/01/04 -68.25 -55.25 6.9 -1.4
2009/01/05 -67.75 -55.25 -2.1 6.0
2009/01/06 -67.25 -55.25 -2.5 4.8
2009/01/07 -71.75 -54.75 3.8 -2.6
2009/01/08 -70.75 -54.75 4.7 -1.3
2009/01/09 -70.25 -54.75 -2.5 4.2
2009/01/10 -69.75 -54.75 -1.8 5.1',
header = TRUE)
Dates = c("2008/12/31", "2009/01/01", "2009/01/02", "2009/01/03", "2009/01/04", "2009/01/05", "2009/01/06", "2009/01/07", "2009/01/08", "2009/01/09", "2009/01/10")
for (m in 1:3)
{
assign(x = paste0("wsp_", m),
value = with(data = eval(expr = parse(text = paste0("data_at_time_", m))),
expr = sqrt(x = ((uwnd ^ 2) + (vwnd ^ 2)))))
}
wsp_results <- data.frame(Dates, mget(x = ls(pattern = "wsp_(\\d)")))
wsp_results
#> Dates wsp_1 wsp_2 wsp_3
#> 1 2008/12/31 8.602325 7.051950 4.049691
#> 2 2009/01/01 7.990620 9.119759 6.964194
#> 3 2009/01/02 5.096077 6.041523 6.129437
#> 4 2009/01/03 8.132035 9.024411 5.590170
#> 5 2009/01/04 8.980535 4.295346 7.040597
#> 6 2009/01/05 9.135097 4.427189 6.356886
#> 7 2009/01/06 3.269557 4.494441 5.412024
#> 8 2009/01/07 2.408319 7.211103 4.604346
#> 9 2009/01/08 8.702299 9.818350 4.876474
#> 10 2009/01/09 4.143670 4.687217 4.887740
#> 11 2009/01/10 4.404543 5.502727 5.408327
Created on 2019-07-21 by the reprex package (v0.3.0)
1 Like
Zakky
July 21, 2019, 10:57am
8
Hello,
Please could you send me your email address so that I can send you a sampled dataset in netcdf format. I want to know how you extract/recall the dataset for a number of three iterations (m in 1:3).
Thank you
system
July 28, 2019, 1:23pm
10
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