roi {nsRFA} | R Documentation |
Region of influence
Description
Formation of clusters for Regional Frequency Analysis: region of influence (Burn, 1990).
Usage
roi (p.ungauged, p.gauged, cod.p, x=NULL, cod=NULL)
roi.hom (p.ungauged, p.gauged, cod.p, x, cod,
test="HW", limit=2, Nsim=500, index=2)
roi.st.year (p.ungauged, p.gauged, cod.p, x, cod,
test="HW", station.year=500, Nsim=500, index=2)
Arguments
x |
vector representing data from many samples defined with |
cod |
array that defines the data subdivision among sites |
index |
if |
p.ungauged |
parameters of the ungauged site (1 row) |
p.gauged |
parameters of gauged sites |
cod.p |
code of gauged sites |
test |
homogeneity test to apply: |
limit |
limit over which regions must be considered heterogeneous: for example 2 for |
Nsim |
number of simulations in |
station.year |
number of station years to form the region |
Details
The Euclidean distance is used.
Given p
different classification variables, the distance between two elements i
and j
is:
d_{i j} = \sqrt{\frac{1}{p} \sum_{h=1}^{p} (x_{h i} - x_{h j})^2}
where x_{h i}
is the value of the h
-th variable of the i
-th element.
Value
roi
returns the ‘region of influence’ for the site defined with p.ungauged
.
It the gauged sites ordered according to the euclidean distance against the site of interest (the distance is evaluated in the space defined by parameters p.ungauged
and p.gauged
).
If x=NULL
and cod=NULL
(default), a data.frame with the ordered sites and the distances against the site of interest is returned.
If x
and cod
are provided, the data.frame will contain also statistics of samples (number of data n
and L-moments).
roi.hom
returns the ‘region of influence’ for the site defined with p.ungauged
.
It returns codes of gauged sites that form an homogeneous region according to the Hosking and Wallis "HW"
or Anderson-Darling "AD"
tests.
The region is formed using distances in the space defined by parameters p.ungauged
and p.gauged
.
roi.st.year
returns the ‘region of influence’ for the site defined with p.ungauged
.
It returns codes of gauged sites that form a region and the risult of homogeneity tests, according to the station-year criterion.
It also return the similarity ranking factor S_i
, the weights w_i
and the regional L-moments as evaluated in the Flood Estimation Handbook (Robson and Reed, 1999).
The region is formed using distances in the space defined by parameters p.ungauged
and p.gauged
.
Note
For information on the package and the Author, and for all the references, see nsRFA
.
See Also
traceWminim
, AD.dist
, HOMTESTS
for the definition of the Hosking and Wallis "HW"
or Anderson-Darling "AD"
tests.
Examples
data(hydroSIMN)
parameters
summary(parameters)
annualflows
summary(annualflows)
x <- annualflows["dato"][,]
cod <- annualflows["cod"][,]
roi(parameters[5,3:5],parameters[-5,3:5],parameters[-5,1])
roi(parameters[5,3:5],parameters[-5,3:5],parameters[-5,1],x,cod)
# roi.hom
#roi.hom(parameters[5,3:5],parameters[-5,3:5],parameters[-5,1],x,cod)
# it takes some time
#roi.hom(parameters[5,3:5],parameters[-5,3:5],parameters[-5,1],x,cod,
# test="AD",limit=.95) # it takes some time
#roi.hom(parameters[8,3:5],parameters[-8,3:5],
# parameters[-8,1],x,cod) # it takes some time
# roi.st.year
roi.st.year(parameters[5,3:5],parameters[-5,3:5],
parameters[-5,1],x,cod)
roi.st.year(parameters[5,3:5],parameters[-5,3:5],parameters[-5,1],
x,cod,test="AD",station.year=100)