HRtemp08: Daily temperatures for Croatia for year 2008
In Envirometrix/plotKML: Visualization of Spatial and Spatio-Temporal Objects in Google Earth

HRtemp08

R Documentation

Daily temperatures for Croatia for year 2008

Description

The daily measurements of temperature (thermometers) for year 2008 kindly contributed by the Croatian National Meteorological Service. HRtemp08 contains 56,608 measurements of temperature (159 stations by 365 days).

Usage

data(HRtemp08)

Format

The HRtemp08 data frames contain the following columns:

NAME: name of the meteorological station
Lon: a numeric vector; x-coordiante / longitude in the WGS84 system
Lat: a numeric vector; y-coordinate / latitude in the WGS84 system
DATE: 'Date' class vector
TEMP: daily temperature measurements in degree C

Note

The precision of the temperature readings in HRtemp08 is tenth of degree C. On most climatological stations temperature is measured three times a day, at 7 a.m., 1 p.m. and 9 p.m. The daily mean can be calculated as a weighted average.

Author(s)

Tomislav Hengl, Melita Percec Tadic and Benedikt Graeler

References

Hengl, T., Heuvelink, G.B.M., Percec Tadic, M., Pebesma, E., (2011) Spatio-temporal prediction of daily temperatures using time-series of MODIS LST images. Theoretical and Applied Climatology, 107(1-2): 265-277. doi: 10.1007/s00704-011-0464-2
AGGM book datasets (http://spatial-analyst.net/book/HRclim2008)

Examples

data(HRtemp08)

## Not run: 
## examples from: http://dx.doi.org/10.1007/s00704-011-0464-2 
library(spacetime)
library(gstat)
library(sp)
sp <- SpatialPoints(HRtemp08[,c("Lon","Lat")])
proj4string(sp) <- CRS("+proj=longlat +datum=WGS84")
HRtemp08.st <- STIDF(sp, time = HRtemp08$DATE-.5, 
     data = HRtemp08[,c("NAME","TEMP")], 
     endTime = as.POSIXct(HRtemp08$DATE+.5))
## Country borders:
con0 <- url("http://www.gadm.org/data/rda/HRV_adm1.RData")
load(con0)
stplot(HRtemp08.st[,"2008-07-02::2008-07-03","TEMP"], 
   na.rm=TRUE, col.regions=SAGA_pal[[1]],
   sp.layout=list("sp.polygons", gadm))

## Load covariates:
con <- url("http://plotkml.r-forge.r-project.org/HRgrid1km.rda")
load(con)
str(HRgrid1km)
sel.s <- c("HRdem","HRdsea","HRtwi","Lat","Lon")
## Prepare static covariates:
begin <- as.Date("2008-01-01")  
endTime <- as.POSIXct(as.Date("2008-12-31"))
sp.grid <- as(HRgrid1km, "SpatialPixels")
HRgrid1km.st0 <- STFDF(sp.grid, time=begin, 
    data=HRgrid1km@data[,sel.s], endTime=endTime)
## Prepare dynamic covariates:
sel.d <- which(!names(HRgrid1km) %in% sel.s)
dates <- sapply(names(HRgrid1km)[sel.d], 
     function(x){strsplit(x, "LST")[[1]][2]}
)
dates <- as.Date(dates, format="%Y_%m_%d")
## Sort values of MODIS LST bands:
m <- data.frame(MODIS.LST = as.vector(unlist(HRgrid1km@data[,sel.d])))
## >10M values!
## Create an object of type STFDF:
HRgrid1km.stD <- STFDF(sp.grid, time=dates-4, data=m, 
     endTime=as.POSIXct(dates+4))

## Overlay in space and time:
HRtemp08.stxy <- spTransform(HRtemp08.st, CRS(proj4string(HRgrid1km)))
ov.s <- over(HRtemp08.stxy, HRgrid1km.st0)
ov.d <- over(HRtemp08.stxy, HRgrid1km.stD)
## Prepare the regression matrix:
regm <- do.call(cbind, list(HRtemp08.stxy@data, ov.s, ov.d))
## Estimate cumulative days:
regm$cday <- floor(unclass(HRtemp08.stxy@endTime)/86400-.5)
str(regm)
## Plot a single station:
scatter.smooth(regm$cday[regm$NAME=="Zavi<c5><be>an"], 
    regm$TEMP[regm$NAME=="Zavi<c5><be>an"], 
    xlab="Cumulative days", 
    ylab="Mean daily temperature (\260C)", 
    ylim=c(-12,28), main="GL039 (Zavi\236an)", 
    col="grey")
## Run PCA so we can filter missing pixels in the MODIS images:
pca <- prcomp(~HRdem+HRdsea+Lat+Lon+HRtwi+MODIS.LST, 
    data=regm, scale.=TRUE)
selc <- c("TEMP","Lon","Lat","cday")
regm.pca <- cbind( regm[-pca$na.action, selc], 
    as.data.frame(pca$x))
## Fit a spatio-temporal regression model:
theta <- min(regm.pca$cday)
lm.HRtemp08 <- lm(TEMP~PC1+PC2+PC3+PC4+PC5+PC6 
     +cos((cday-theta)*pi/180), data=regm.pca)
summary(lm.HRtemp08)

## Prediction locations -> focus on Istria:
data(LST)
gridded(LST) <- ~lon+lat
proj4string(LST) <- CRS("+proj=longlat +datum=WGS84")
LST.xy <- reproject(LST[1], proj4string(HRgrid1km))
LST.xy <- as(LST.xy, "SpatialPixels")
## targeted dates:
t.dates <- as.Date(c("2008-02-01","2008-05-01","2008-08-01"), 
     format="%Y-%m-%d")
LST.st <- STF(geometry(LST.xy), time=t.dates)
## get values of covariates:
ov.s.IS <- over(LST.st, HRgrid1km.st0)
ov.d.IS <- over(LST.st, HRgrid1km.stD)
LST.stdf <- STFDF(geometry(LST.xy), time=t.dates, 
    data=cbind(ov.s.IS, ov.d.IS))
## predict Principal Components:
LST.pca <- as.data.frame(predict(pca, LST.stdf@data))
LST.stdf@data[,paste0("PC",1:6)] <- LST.pca
cday.l <- as.vector(sapply(
    floor(unclass(LST.stdf@endTime)/86400-.5), 
    rep, nrow(LST.xy@coords)))
LST.stdf@data[,"cday"] <- cday.l
stplot(LST.stdf[,,"PC1"], col.regions=SAGA_pal[[1]])
stplot(LST.stdf[,,"PC2"], col.regions=SAGA_pal[[1]])

## Predict spatio-temporal regression:
LST.stdf@data[,"TEMP.reg"] <- predict(lm.HRtemp08, 
     newdata=LST.stdf@data)
## Plot predictions:
gadm.ll <- as(spTransform(gadm, 
     CRS(proj4string(HRgrid1km))), "SpatialLines")
stplot(LST.stdf[,,"TEMP.reg"], col.regions=SAGA_pal[[1]],
  sp.layout=list( list("sp.lines", gadm.ll),
   list("sp.points", HRtemp08.stxy, col="black", pch=19) )
  )

## End(Not run)

Envirometrix/plotKML documentation built on June 13, 2022, 11:21 p.m.