Cockpit: "Correlations"

Discover correlations between variables and investigate correlations in detail.


  Video available: The easiest way to get acquainted with the workflow of this cockpit is to watch the video tutorial in our Video Academy

Overview

  1. Overview of Correlations: A matrix showing pairwise correlations of variables (first view tab), and a list of all variables correlated with one chosen target variable (second view tab). In these views, you select the variables shown in detail in the rest of the cockpit.
  2. Scatter Plot for selected variable pair: Large detail scatter plot for variable pair selected in the overview. Possibility to select points, e.g., outliers.
  3. Correlation of selected pair per category (Drill-Down): The Pearson correlation of the selected variable pair compared for different categories or time periods.
  4. Time Series: Time series plots of the selected variables with the possibility to select records, and to zoom to selected time ranges.
  5. Table: A table-like view of single values that can be shown on demand.



Overview of Correlations


The "Pairwise Correlation" view is a half-matrix displaying the correlation for each pair-wise combination of variables.

The "Target Correlation" view shows a list of all variables, each Pearson-correlated with one target variable.


Scatter Plot for the selected variable pair


This view shows the currently selected variable pair as a detailed two-dimensional scatterplot. In addition, a regression line is displayed on top of the points. In the view-specific options of the view title menu, the order of the regression line can be set (linear, square or cubic).

It is also possible to select points (data records) in the diagram by dragging the left mouse button. Selected points are brought into focus, not selected points are shaded in gray. Two regression lines are now displayed: one line for the records in the focus, another (gray) regression line for the records outside the focus. The selection affects the remaining diagrams. For example, the "Pairwise Correlation" diagram now uses the currently selected records as a basis for calculating the correlation for the combinations of variables.

Further options in the view title menu, when clicking the label "Scatter Plot":


Correlation of selected pair per category (Drill Down)

These views show the Pearson Correlation of the selected variable pair for different categories, using colors. Each colored cell (or bar) aggregates the data that falls within the corresponding (combination of) categories.

The views can be used to perform selections of categories by clicking the category labels, which defines a focus for the other views. If a focus was already defined in other views, the Drill-Down views only consider the data records of the focus.


Time Series


These plots show variables over time. If the time axis has a regular raster, the timeline is connected as line graph. If more than one variable is shown, there are two ways of distinguishing them:

Key actions:

The diagram offers several options when clicking the view title "Time Series". The most important ones are:


Table ('Focus data records')


A table showing the single values. Only considers the data records in focus. Click the header of a column to sort the table by it. To change the set of displayed columns, click the header "Shown: 103 of 210 data attributes". Click single rows or drag a line with the left mouse button to select records, putting them into focus.

Exporting: A key use case of the table is exporting a selected subset of the data. To export the current state of the table, click the view title "Focus data records", and then "Data export".


Roles supported by this cockpit

The following roles can be given to data attibutes in this cockpit. Use the icon in the toolbar to adjust them.



License Statement for the Photovoltaic and Weather dataset used for Screenshots:
"Contains public sector information licensed under the Open Government Licence v3.0."
Source of Dataset (in its original form): https://data.london.gov.uk/dataset/photovoltaic--pv--solar-panel-energy-generation-data
License: UK Open Government Licence OGL 3: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
Dataset was modified (e.g. columns renamed) for easier communication of Visplore USPs.