Plotting your data

There are currently two ways of plotting your data 1) basic time series plots and 2) statistical process control charts (SPC) (see Statistical process control for radiotherapy quality assurance).

Note: Anywhere you see a little chart icon () next to a test you can click on it to automatically be taken to a chart of that data

To access the chart interface choose the Charts menu item from the Review Data dropdown menu at the top of any page.

The basic functionality of the charts page should be fairly self explanatory. First select the units you are interested in, and then select the test lists/tests you would like to plot data for.

There are a number of chart options which you can change:

• Lines: Controls whether series have lines displayed or just the points
• Refs/Tols: Control whether reference & tolerance data is shown
• Legend: Toggle display of legend
• Combine test data for unit: Combine results for the same test from different test lists into a single series
• Plot relative to reference values: If selected, the absolute difference is plotted for tests with absolute tolerances set or with reference values of zero, otherwise the percent difference is plotted.

You can leave the Chart Options with their default settings or add/remove the legend, data lines, reference & tolerances etc. To create an SPC choose the Control Chart option from the Chart Options - Type: dropdown.

Once you are happy with the options, click the Generate Chart button.

The time series plots are interactive and you can pan/zoom the data using the sliders at the bottom of the chart. At this point it is not possible to directly save a time series plot to an image file and you will need to create a screen capture if you want to send someone the image. You can however send someone the URL located in the link text box under the chart options.

To save a control chart, right click and select Save Image As.

Notes on Control Charts

To specify where your baseline data comes from you can use the Date Filters under the Generate Chart button. For example if there was a reference change on 5 Nov 2012 then you would set the From: date filter to 5 Nov 2012 and the baseline points will be taken starting on that date.