Introduction
There are two functions available in clifro to create
requisite cfStation objects to send queries to retrieve
data via clifro. The first one is to search for stations
using the cf_find_station function as detailed in the choose stations vignette. The other
function that creates cfStation objects is the
cf_station function that requires comma separated agent
numbers as the only input. This vignette covers the construction of a
cfStation object via the cf_station function,
and then shows examples of plotting and visualising the station’s
locations using KML files or within R using the ggmap package.
Creating a cfStation object from agent numbers
This is the simplest method to create a cfStation
object, simply supply the cf_station function the comma
separated agent numbers. The following stations are (or were) located
around Lake Tekapo in Canterbury, in the South Island of New
Zealand:
- Coal (Ski Field)
- Macaulay (Mt Gerald)
- South Opua
- Mount John
- Lake Tekapo Ews
- Godley Peaks
- Lilybank
lake.tekapo.st = cf_station(12709, 35567, 39557, 4630, 24945, 4616, 4602)
lake.tekapo.st[, c("name", "agent", "start", "end", "open")]## name agent start end open
## 1 Coal @ Skifield 12709 1989-02-01 2020-09-01 02:00:00 TRUE
## 2 Macaulay@Mt Gerald 35567 1990-07-04 2020-09-01 02:00:00 TRUE
## 3 Lake Tekapo Ews 24945 2003-06-18 2020-09-01 02:00:00 TRUE
## 4 South Opua @ South Opua 39557 2011-09-28 2020-09-01 02:00:00 TRUE
## 5 Lilybank Station 4602 1950-01-01 1992-09-30 00:00:00 FALSE
## 6 Mt John 4630 1962-10-01 1988-01-01 00:00:00 FALSE
## 7 Godley Peaks, Tekapo 4616 1914-01-01 1976-06-01 00:00:00 FALSEWe can see that subsetting lake.tekapo.st acts just like
a data.frame object, although it is technically a
cfStation object. Most of the common
data.frame methods work on cfStation
objects.
Adding more stations
To add more stations to this list the addition sign is used. Any repeated stations are removed and the resulting list is ordered by the end dates first and then by the stations’ start dates.
added.stations.st = lake.tekapo.st +
cf_station() +
cf_find_station("lighthouse", status = "all")
added.stations.st[, c("name", "agent", "start", "end", "open")]## name agent start end open
## 1 Reefton Ews 3925 1960-08-01 2020-09-01 TRUE
## 2 Coal @ Skifield 12709 1989-02-01 2020-09-01 TRUE
## 3 Macaulay@Mt Gerald 35567 1990-07-04 2020-09-01 TRUE
## 4 Lake Tekapo Ews 24945 2003-06-18 2020-09-01 TRUE
## 5 South Opua @ South Opua 39557 2011-09-28 2020-09-01 TRUE
## 6 Tiri Tiri Lighthouse 1401 1946-02-01 2020-08-31 TRUE
## 7 Kapoaiaia At Lighthouse 42673 1998-05-17 2020-08-31 TRUE
## 8 Orakei Lighthouse 44394 2020-05-01 2020-08-31 TRUE
## 9 Rangitoto Lighthouse 44400 2020-05-01 2020-08-31 TRUE
## 10 Lilybank Station 4602 1950-01-01 1992-09-30 FALSE
## 11 Mt John 4630 1962-10-01 1988-01-01 FALSE
## 12 Cape Brett Lighthouse 1197 1934-11-01 1978-10-01 FALSE
## 13 Nugget Lighthouse B 5894 1975-03-01 1977-08-31 FALSE
## 14 Nugget Lighthouse A 5895 1975-03-01 1977-08-31 FALSE
## 15 Godley Peaks, Tekapo 4616 1914-01-01 1976-06-01 FALSE
## 16 Moeraki Lighthouse 5325 1935-10-01 1975-06-01 FALSEThe above code chunk adds the 7 stations around Lake Tekapo, the
subscription-free reefton EWS station (cf_station()), and
all stations presumably located (currently or historically) on or near a
lighthouse.
Allowing multiple searches is not currently available using the web
portal, CliFlo, but the above code demonstrates how easy it can be in
clifro.
Visualising the station locations
CliFlo does not currently have any visualisation tools to aid in the selection of stations which can make the task of choosing geographically suitable stations a hard one.
Using KML files
The cf_save_kml functionality was introduced in the choose stations vignette and this
function can be used on any cfStation object. To return a
KML file showing all the stations within our
added.stations.st object we just run
cf_save_kml(added.stations.st) in R and the KML file is
returned.
