xtractomatic: Routines to simplify data extraction using ERD's ERDDAP web service.

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Description

The xtractomatic package is a set of routines to simplify accessing data using ERD's ERDDAP data web service. The package contains three main functions and two helper functions.

Main Functions

  • xtracto - Extracts an environmental variable along a track defined by its longtiude, latitude and time.

  • xtracto_3D - Extracts an environmental variable in a 3D (longitude,latitude, time) bounding box

  • xtractogon - Extracts an environmental variable in a spatial polygon through time.

Helper Functions

  • searchData - Searches to see if given string is contained in the datasetname, varname, or dtypename. See ?searchData.

  • getInfo - Returns information about a given environmental variable. See ?getInfo.

@section Details: When the xtractomatic package is loaded ("library(xtractomatic)") a data structure called erddapStruct is automatically loaded into memory, and is explicitly used in searchData and getInfo, as well implicitly in the other functions. Not all ERDDAP variables are accessed in the routines, and this structure defines information about the datasets, including:

  • dtypename

  • datasetname

  • longname

  • varname

  • hasAlt

  • latSouth

  • lon360

  • minLongitude

  • maxLongitude

  • longitudeSpacing

  • minLatitude

  • maxLatitude

  • latitudeSpacing

  • minAltitude

  • maxAltitude

  • minTime

  • maxTime

  • timeSpacing

  • infoUrl

Besides the terse help documents, more detail in using the functions are given in the included vignette "Usingxtractomatic". The datasets used in the vignette are included in the "data" directory.