Tim

Tim Kent's Blog

SSRS 2008 – Lattice Charts (Small Multiples)

Update: Nick Barclay has made some nice tweaks to the sample here

Whenever I’m reading Visualisation books and in particular the best practice examples, I always find myself wondering whether:

a) it’s possible with Reporting Services? and

b) it can look as good with Reporting Services?

and this was the case whilst I finally got round to starting to read Few’s new book Now You See It. One of the key principles of data visualisation is “Compared to What?”.  It’s all very well presenting the information in a clear fashion but without context it’s hard to argue it’s worth.

The use of a matrix of charts (lattice charts, trellis charts) allows the eye to very easily compare data both horizontally and vertically.  This method of display is also known as “Small Multiples” – a term coined by Tufte in his book - Envisioning Information.  These charts also allow you to easily add additional dimensions to a two-dimensional display.

I’m sure many of you will have used SSRS inline-charts before in a table (my bullet chart examples use this method) but it’s also possible to do this with the matrix object as well.  I’m not going to explain in detail the method to produce in-line charts in SSRS as it’s well documented already in this msdn article but in summary you simply set up your matrix with the appropriate row and column groupings, design your chart outside of the matrix then when it’s ready simply drop it in the data cell. 

image

One thing to make sure you do is to change the maximum setting for your value axis to be the maximum value from your entire dataset using a scoped field expression (=MAX(Fields!Sales_Amount.Value, "DataSet1")).  This ensures that all the axes have the same scale - without this you will be visually comparing apples with oranges!.

With a bit of work on the formatting, the result looks pretty reasonable (though the spread of AdventureWorks data isn’t that great).  You can easily see which region is performing best and which category has the best sales.

As usual you can download the sample: MatrixCharts.rdl (26.11 kb)

image

 

Loading