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Tip
titleHelp

DataSHIELD support is freely available in the DataSHIELD forum by the DataSHIELD community. Please use this as the first port of call for any problems you may be having, it is monitored closely for new threads.

DataSHIELD bespoke user support and also user training classes are offered on a fee-paying basis. Please enquire at datashield@newcastle.ac.uk for current prices. 

Introduction

This is the fourth in a 6-part DataSHIELD tutorial series. Please see below for links to all prior and subsequent parts:

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Start R/RStudio

Load Packages

Code Block
xml
xml
#load libraries
library(DSI)
library(DSOpal)
library(dsBaseClient)

Build your login dataframe 

Code Block
languagexml
titleBuild your login dataframe
builder <- DSI::newDSLoginBuilder()
builder$append(server = "study1",  url = "http://192.168.56.100:8080/",
               user = "administrator", password = "datashield_test&",
               table = "CNSIM.CNSIM1", driver = "OpalDriver")
builder$append(server = "study2", url = "http://192.168.56.101:8080/",
               user = "administrator", password = "datashield_test&",
               table = "CNSIM.CNSIM2", driver = "OpalDriver")

logindata <- builder$build()

connections <- DSI::datashield.login(logins = logindata, assign = TRUE, symbol = "D")

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Code Block
languagebash
DSI::datashield.logout(connections)


Generating graphs

It is currently possible to produce 4 types of graphs in DataSHIELD: histograms, contour plots, heatmap plots and scatter plots.


Histograms 

Tip
titleHistograms

In the default method of generating a DataSHIELD histogram outliers are not shown as these are potentially disclosive. The text summary of the function printed to the client screen informs the user of the presence of classes (bins) with a count smaller than the minimal cell count set by data providers. 

Note that a small random number is added to the minimum and maximum values of the range of the input variable. Therefore each user should expect slightly different printed results from those shown below:

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contour_plots
contour_plots

Contour plots 

Contour plots are used to visualize a correlation pattern.

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heatmap_plots
heatmap_plots

Heat map plots 

An alternative way to visualise correlation between variables is via a heat map plot.

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Tip

The functions ds.contourPlot and ds.heatmapPlot use the range (minimum and maximum values) of the x and y vectors in the process of generating the graph. But in DataSHIELD the minimum and maximum values cannot be returned because they are potentially disclosive; hence what is actually returned for these plots is the 'obscured' minimum and maximum. 

Saving Graphs / Plots in R Studio

  • Any plots will appear in the bottom right window in R Studio, within the  plot  tab
  • Select  export  save as image

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  • The plot will now be accessible from your Home folder directory structure. 

Conclusion

The next part in this DataSHIELD tutorial series is: 

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