Description Usage Arguments Details Value Author(s) References See Also Examples
fitQmap
identifyes the parameters of different quantile mapping
methods. doQmap
performs quantile mapping using previously
identified parameters.
1 2 |
obs |
|
mod |
|
method |
A character string indicating the method to be used. See Details. |
x |
|
fobj |
output from |
... |
arguments passed to the method specified by |
The method
argument decides upon which method for quantile
mapping is used:
"PTF"
selects fitQmapPTF
.
"DIST"
selects fitQmapDIST
"RQUANT"
selects fitQmapRQUANT
"QUANT"
selects fitQmapQUANT
"SSPLIN"
selects fitQmapSSPLIN
doQmap
investigates the class of fobj
and chooses the
appropriate method for quantile mapping.
fitQmap
returns an object which class and structure depends on
the selected method
(see Details).
doQmap
returns a numeric
vector, matrix
or
data.frame
depending on the format of x
.
Lukas Gudmundsson
Gudmundsson, L.; Bremnes, J. B.; Haugen, J. E. & Engen-Skaugen, T. Technical Note: Downscaling RCM precipitation to the station scale using statistical transformations - a comparison of methods, Hydrology and Earth System Sciences, 2012, 16, 3383-3390, doi:10.5194/hess-16-3383-2012.
fitQmapDIST
, fitQmapPTF
,
fitQmapRQUANT
, fitQmapQUANT
,
fitQmapSSPLIN
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | data(obsprecip)
data(modprecip)
## call to fitQmapPTF and doQmapPTF
qm1.fit <- fitQmap(obsprecip,modprecip,
method="PTF",
transfun="expasympt",
cost="RSS",wett.day=TRUE)
qm1 <- doQmap(modprecip,qm1.fit)
## call to fitQmapDIST and doQmapDIST
qm2.fit <- fitQmap(sqrt(obsprecip),sqrt(modprecip),
method="DIST",qstep=0.001,
transfun="berngamma")
qm2 <- doQmap(sqrt(modprecip),qm2.fit)^2
## call to fitQmapRQUANT and doQmapRQUANT
qm3.fit <- fitQmap(obsprecip,modprecip,
method="RQUANT",qstep=0.01)
qm3 <- doQmap(modprecip,qm3.fit,type="linear")
## call to fitQmapRQUANT and doQmapRQUANT
qm4.fit <- fitQmap(obsprecip,modprecip,
method="QUANT",qstep=0.01)
qm4 <- doQmap(modprecip,qm4.fit,type="tricub")
## call to fitQmapSSPLIN and doQmapSSPLIN
qm5.fit <- fitQmap(obsprecip,modprecip,qstep=0.01,
method="SSPLIN")
qm5 <- doQmap(modprecip,qm5.fit)
sqrtquant <- function(x,qstep=0.001){
qq <- quantile(x,prob=seq(0,1,by=qstep))
sqrt(qq)
}
op <- par(mfrow=c(1,3))
for(i in 1:3){
plot(sqrtquant(modprecip[,i]),
sqrtquant(obsprecip[,i]),pch=19,col="gray",
main=names(obsprecip)[i])
lines(sqrtquant(modprecip[,i]),
sqrtquant(qm1[,i]),col=1)
lines(sqrtquant(modprecip[,i]),
sqrtquant(qm2[,i]),col=2)
lines(sqrtquant(modprecip[,i]),
sqrtquant(qm3[,i]),col=3)
lines(sqrtquant(modprecip[,i]),
sqrtquant(qm4[,i]),col=4)
lines(sqrtquant(modprecip[,i]),
sqrtquant(qm5[,i]),col=5)
}
legend("topleft",
legend=c("PTF","DIST","RQUANT","QUANT","SSPLIN"),
lty=1, col=1:5)
par(op)
|
Loading required package: fitdistrplus
Loading required package: MASS
Loading required package: survival
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