Functions within the UKFE package for importing data
There are a range of functions for importing data, as set out in this section.
Annual maximum data
An annual maximum series can be obtained for sites suitable for
pooling using the GetAM() function. This extracts data from
the embedded AMSP data frame within the UKFE package. For
other AMAX series available from the NRFA Peak Flow Dataset, the
AMImport() function can be used, as can the
GetDataNRFA() function (with Type = "AMAX").
The former function imports the data from the AM files and excludes the
years classed as rejected. The latter function extracts the AMAX using
the NRFA API. If you have a flow time series, the
AnnualStat() function can be used to extract the water year
AMAX (or any other annual statistic of interest). The following example
uses the GetAM() option.
# Extract the AMAX data for NRFA site 55002 and save to an object called 'AM.55002'
AM.55002 <- GetAM(55002)
# View the head of the AMAX series
head(AM.55002)
#> Date Flow id
#> 1 1974-02-12 457.894 55002
#> 2 1975-01-22 410.053 55002
#> 3 1975-12-02 364.079 55002
#> 4 1977-02-03 286.690 55002
#> 5 1977-11-20 318.908 55002
#> 6 1978-12-14 397.771 55002
# Plot the AMAX data
AMplot(AM.55002)
The AMplot() function returns a time series bar plot of
the AMAX series.
Catchment descriptors
Catchment descriptors (CDs) from the NRFA can be brought into the ‘R’
environment using the GetCDs() function. For gauged sites
that are suitable for pooling or QMED, these are extracted from the
QMEDData data frame, otherwise, they are extracted using
the NRFA API. Note that if they are brought in from the NRFA API (when
not suitable for QMED or pooling), some of the descriptors differ; for
example, the gauge location is provided rather than the catchment
centroid. There will be a warning message when this happens. An example
of using the GetCDs() function to view the catchment
descriptors for the gauge with an NRFA ID of 39001 is as follows:
# Extract and view catchment descriptors for NRFA gauge 39001
GetCDs(39001)
#> Descriptor Value
#> 1 AREA 9930.7975
#> 2 ALTBAR 109.0000
#> 3 ASPBAR 108.0000
#> 4 ASPVAR 0.0800
#> 5 BFIHOST19 0.6790
#> 6 DPLBAR 139.8700
#> 7 DPSBAR 42.0000
#> 8 FARL 0.9420
#> 9 FPEXT 0.1476
#> 10 LDP 269.5500
#> 11 PROPWET 0.3000
#> 12 RMED-1H 10.8000
#> 13 RMED-1D 32.7000
#> 14 RMED-2D 41.5000
#> 15 SAAR 706.0000
#> 16 SAAR4170 724.0000
#> 17 SPRHOST 26.9400
#> 18 URBEXT2000 0.0664
#> 19 Easting 462899.0000
#> 20 Northing 187850.0000
#> 21 QMEDfse 1.0280
#> 22 N 140.0000
#> 23 URBEXT1990 0.0426
#> 24 BFIHOST 0.6530It’s useful to store them as an ‘object’ for use with other
functions, in which case you can give them a name. You can assign the
data to the named object using <-. For example:
# Extract catchment descriptors for NRFA gauge 39001 and store in an object called
# 'CDs.39001'
CDs.39001 <- GetCDs(39001)Then, when you wish to view them, the object name
CDs.39001 can be entered into the console.
If you wish to derive CDs from an XML file for catchments that aren’t
suitable for pooling or QMED, or are not gauged at all, you can use the
CDsXML() function. The file path will need to be used. For
Windows operating systems, the backslashes will need to be changed to
forward slashes, or the file path will need to be stated as follows:
r"{my\file\path}". For example, you can import some
descriptors downloaded from the FEH Web Service as follows:
# Extract catchment descriptors from an xml file and store in an object called
# 'CDs.MySite'
CDs.MySite <- CDsXML("C:/Data/FEH_Catchment_384200_458200.xml")
# As above but retaining backslashes in the file path
CDs.MySite <- CDsXML(r"{C:\Data\FEH_Catchment_384200_458200.xml}")Or if importing CDs from the NRFA Peak Flow Dataset:
Other hydrological data retrieval functions using APIs
There are several functions with names starting with
GetData that extract data from the websites of different
organisations using their APIs. These are:
GetDataEA_QH(): Extracts flow or level data from the Environment Agency’s Hydrology Data Explorer.GetDataEA_Rain(): Extracts rainfall data from the Environment Agency’s Hydrology Data Explorer.GetDataMetOffice(): Extracts regional mean (monthly, seasonal and annual) temperature or rainfall from the UK Met Office. Sunshine duration is also available.GetDataNRFA(): Extracts National River Flow Archive data (daily mean flow or catchment rainfall, AMAX, POT, gaugings and metadata).GetDataSEPA_QH(): Extracts flow or level data from the Scottish Environment Protection Agency.GetDataSEPA_Rain(): Extracts hourly rainfall data from the Scottish Environment Protection Agency.
There are examples for all of these within each function’s help file.
QMED
The GetQMED() function can be used to import the QMED
data from the QMEDData data frame (derived from AMAX data).
If it is not in that data frame, it automatically imports the AMAX data
using the GetAM() function and calculates the median.