rerddapXtracto (Version 0.4.4)

rerddapXtracto - R package for accessing environmental data using rerddap

This version is updated to work with rerddap Version 0.6.0, earlier versions can fail. This version is now on CRAN, as is plotdap.

The big change with this version is the ability to cross the dateline for datasets that are on a (-180, 180) longitude grid. Some caveats when trying to make an extract that crosses the dateline:

• Request must be on a (0, 360) longitude grid
• Several of the checks that the request makes sense are disabled if the request

cross the dateline and the dataset is on a (-180, 180) longitude grid.

• User therefore has more responsibility to check that the request makes sense

for the dataset being accessed.

Also, several of the internal functions have been refactored, making the code in the main functions a little cleaner.

rerddapXtracto is an R package developed to subset and extract satellite and other oceanographic related data from a remote ERDDAP server. The program can extract data for a moving point in time along a user-supplied set of longitude, latitude, time and depth (new in this version) points; in a 3D bounding box; or within a polygon (through time).

New in this version is that a track can now move in (x, y, z, t) space if appropriate for the dataset being accessed. And two plotting functions have been added, plotTrack() and plotBox() that make use of the plotdap package. See the new rerdapXtracto vignette. A lot of the code has been reworked, in particular the handling of time, and in the formation of the requests to rerddap.

There are three main data extraction functions in the rerddapXtracto package:

• rxtracto <- function(dataInfo, parameter = NULL, xcoord = NULL, ycoord = NULL, zcoord = NULL, tcoord = NULL, xlen = 0., ylen = 0., zlen = 0., xName = 'longitude', yName = 'latitude', zName = 'altitude', tName = 'time', urlbase = 'http://upwell.pfeg.noaa.gov/erddap', verbose = FALSE)

• rxtracto_3D <- function(dataInfo, parameter = NULL, xcoord = NULL, ycoord = NULL, zcoord = NULL, tcoord = NULL, xName = 'longitude', yName = 'latitude', zName = 'altitude', tName = 'time', urlbase = 'http://upwell.pfeg.noaa.gov/erddap', verbose = FALSE)

• rxtractogon <- function(dataInfo, parameter, xcoord = NULL, ycoord = NULL, zcoord = NULL, tcoord = NULL, xName = 'longitude', yName = 'latitude', zName = 'altitude', tName = 'time', urlbase = 'http://upwell.pfeg.noaa.gov/erddap', verbose = FALSE)

and two functions for producing maps:

• plotTrack <- function(resp, xcoord, ycoord, tcoord, plotColor = 'viridis', myFunc = NA, mapData = NULL, crs = NULL, animate = FALSE, cumulative = FALSE, name = NA, shape = 20, size = .5)

• plotBBox <- function(resp, plotColor = 'viridis', time = NA, myFunc = NA, mapData = NULL, crs = NULL, animate = FALSE, cumulative = FALSE, name = NA, maxpixels = 10000)

rerddapXtracto uses the rerddap, ncdf4 , parsedate, plotdap and sp packages , and these packages (and the packages imported by these packages) must be installed first or rerddapXtracto will fail to install.

install.packages("ncdf4") 
install.packages("parsedate") 
install.packages("plotdap") 
install.packages("rerddap") 
install.packages("sp")

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