##Background The Hilltop.R file contains R functions for interacting with a Hilltop Time Series Server using Hilltop specific calls. Hilltop servers can also provide some information in OGC compliant formats, basic documentation is available by entering a Hilltop Server url
The file WQualityImport_Example.R demonstrates the use of some of the Hilltop.R functions for downloading water quality data from a Hilltop server, and contains some test urls.
Note this example file was built before the helper function anyXmlParse() was written and the urls are http requests, hence it uses xmlParse() to parse the XML. If you need to parse data from a secure server replace xmlParse() with anyXmlParse()
##Packages The functions use the R packages XML, reshape2, plyr and RCurl. These packages are checked for and loaded when the code is run.
##Using the code
Copy, download or fork the code.
Use source(Hilltop.R) to make the functions available.
##Functions ###hilltopSiteList Given a server endpoint, requests and parses a SiteList request and generates a dataframe of sites.
###hilltopDsMeasList Helper function. Takes a parsed xml document from a Hilltop MeasurementList at a Site request. Returns a dataframe of the datasource information and measurements names.
###hilltopMeasInfoList Helper function. Takes an parsed xml document from a Hilltop MeasurementList at a Site request. Returns a dataframe of the measurement information and datasources.
###hilltopDsMeasListFull Takes an xml document from a Hilltop MeasurementList at a Site request. Returns a dataframe of all of the datasource and measurement information combined. Occasional issues with some datasources and measurements, hilltopMeasInfoListExtra is another option.
###hilltopMeasInfoListExtra Helper function. Takes an xml document from a Hilltop MeasurementList at a Site request. Returns a dataframe of the measurement information and some datasource information. Similar to hilltopDsMeasListFull, but with limited datasource information.
###hilltopValueHelper Helper function Returns the appropriate xml value depending whether the value of interest is from a named node, or is a named parameter.
###hilltopAttributeHelper Helper function Returns the appropriate xml attribute name depending whether the attribute of interest is from a named node, or is a named parameter.
###hilltopMeasurementToDF
Helper function
Reads the nodes within a the Measurement node of a parsed Hilltop XML document from a request such as dataxml<-anyXmlParse(url).
Returns a dataframe of the data for each timestamp.
Handles missing results and doen't require prior knowledge of parameter names.
Handles true measurements and WQ Sample requests
###hilltopDataSourceToDF
Helper function
Reads the nodes within a the DataSource ItemInfo node of a parsed Hilltop XML document from a request such as dataxml<-anyXmlParse(url).
Returns a dataframe of the Info for each Item.
Handles missing results and doen't require prior knowledge of the items.
###hilltopMeasurement
Main function that converts a Hilltop XML document from a request such as dataxml<-anyXmlParse(url) for a water quality measurement into a dataframe that contains the measurement information.
It returns a dataframe of the data for each timestamp, including DataSource Information and the Site Name.
This dataframe can be merged with a WQ Sample dataframe processed using hilltopMeasurementToDF
###is.hilltopXml
Function to check whether parsed xml is from a valid Hilltop Server. Returns TRUE or FALSE accordingly.
###anyXmlParse
Helper function
Parses the xml from a url. Checks whether the url is a secure server, if not uses xmlParse (XML Library). If it is it uses RCurl functions to parse the data.
###hilltopEnsembleStatBkgnd Helper function Given the parsed xml from an Ensemble Statistics request. Returns a single line dataframe of the STatistics background information This needs to be combined with the stats themselves to get a full dataframe. see hilltopEnsembleStatsFull, and hilltopEnsembleStatsByTimePeriod
###hilltopEnsembleStatByTimePeriod Helper function Given the parsed xml from an EnsembleStats Request. Returns the statistics for each time period (depending whether hourly, daily, or monthly stats)
###hilltopEnsembleStatFull Takes the parsed xml from an EnsembleStats Request. Returns a dataframe of the statistics for the period, along with the background information such as site, measurement, units and statistic.