demo/pegel.R

In sos4R: Client for OGC Sensor Observation Services

############################################################################## #
# Copyright (C) 2019 by 52 North                                               #
# Initiative for Geospatial Open Source Software GmbH                          #
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# Contact: Andreas Wytzisk                                                     #
# 52 North Initiative for Geospatial Open Source Software GmbH                 #
# Martin-Luther-King-Weg 24                                                    #
# 48155 Muenster, Germany                                                      #
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# Free Software Foundation.                                                    #
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# this program (see gpl-2.0.txt). If not, write to the Free Software           #
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# Author: Daniel Nuest (daniel.nuest@uni-muenster.de)                          #
# Project: sos4R - https://github.com/52North/sos4R                            #
#                                                                              #
############################################################################## #

library("sos4R")
library("ggplot2")
library("latticeExtra")
library("quantreg")

##############################################################################
# PegelOnlineSOS
pegelsos <- SOS(url = "http://pegelonline.wsv.de/webservices/gis/gdi-sos",
                version = "1.0.0")

pegelsos

# what data do I get?
cat("\nNames of offerings:\n")
print(names(sosOfferings(pegelsos)))

# let's find interesting data
# Bake_Z: http://www.pegelonline.wsv.de/gast/stammdaten?pegelnr=9510066
procs <- sosProcedures(pegelsos)[["WASSERSTAND_ROHDATEN"]]
contain_bake <- procs %in% grep("*Wasserstand-Bake*", procs, value=TRUE)
baken <- subset(procs, contain_bake)
cat("\nGauges in Northern Sea:\n")
print(baken)

# what?
wasserstand_roh <- sosOfferings(pegelsos)[["WASSERSTAND_ROHDATEN"]]
# what?
wasserstand <- sosObservedProperties(wasserstand_roh)[1]
# must be "Wasserstand":

# when?
tPeriod.days <- 3 # 30
tPeriod <- sosCreateEventTimeList(
		time = sosCreateTimePeriod(
				sos = pegelsos,
				begin = Sys.time() - (3600 * 24 * tPeriod.days),
				end = Sys.time()))
#encodeXML(tPeriod[[1]], pegelsos)

# three procedures, but only getting 1 element with one procedure...
cat("\nRequesting data... \n")
pegelObs <- getObservation(sos = pegelsos,
		observedProperty = wasserstand,
		offering = wasserstand_roh,
		procedure = baken[c(1, 3)],
		eventTime = tPeriod)

# show parts of the data frame:
cat("\nData excerpts:\n")
sosResult(pegelObs[[1]])[1:2,]
sosResult(pegelObs)[1:10,]

# not enough info? got field descriptions as attributes for each column:
cat("\nMetadata for two values:\n")
attributes(sosResult(pegelObs[[1]])$SamplingTime) # TIME
attributes(sosResult(pegelObs[[1]])$Wasserstand) # actual value

# do something with the data! (here we clean up first all values below 0)
r1 <- sosResult(pegelObs[[1]])
range(r1$Wasserstand)
r1clean <- subset(r1, Wasserstand > 0)
range(r1clean$Wasserstand)

r2 <- sosResult(pegelObs[[2]])
range(r2$Wasserstand)
r2clean <- subset(r2, Wasserstand > 0)
range(r2clean$Wasserstand)

plot(r1clean$SamplingTime, r1clean$Wasserstand, type = "l", ylim = c(200,800),
		lty = "solid", col = "blue",
		main = paste("Water level at", sosProcedures(pegelObs[c(1,2)])))
lines(r2clean$SamplingTime, r2clean$Wasserstand, type = "l", col = "orange",
		lty = "twodash",
		main = paste("Water level at", sosProcedures(pegelObs[[2]])))
par(ask = TRUE)

# Plot a quantile regression line with standard error bounds, using the quantreg package.
r1plot <- xyplot(r1clean$Wasserstand ~ r1clean$SamplingTime, r1clean, type = "l",
		col = "orange", main = paste0(sosProcedures(pegelObs[[1]]),
				" with quantile regression line and error bounds"),
		xlab = "Time", ylab = "Water level")

r1plot <- r1plot + layer(panel.quantile(x, y, tau = c(.95, .5, .05)))
show(r1plot)

###################################
# Demo finished, try another one! #
###################################