Dimensions - simple overview?

[cthomas2]

Hello,

I was hoping someone could explain to me how the dimensions work in a Chart (or in general, but I am currently working on a chart).

I have 2 confusion points, firstly it seems the order that the dimensions are in on the "Used Dimensions" section impact what is displayed on the X & Y axis... but I can have as many dimensions as I want... how do all the extra dimensions get taken into consideration? Is there a guide how this works (I can't find one)? Right now it seems my expression creates the Y axis and the first dimension is displayed on the X-axis, but doesn't seem consistent... read next part please...

Second, on my specific chart, I have 3 dimensions, let's call them 1, 2 and 3 (in order). I noticed when I apply a filter to Dimension 1 and the filter is down to a single result, Dimension 2 now appears on the X axis instead. I do not understand this logic or why it does this. I can understand that it might not make sense to keep Dimension 1 on the X-axis, but how can I take advantage (or what exactly is it trying to do) so I can have it display a chart that makes sense? Changing Dimension 3 to dimension 2 spot does not produce a graph I am happy with either, but I'm not sure how to get it to do something I would prefer without adding more dimensions which then impacts the larger view of the chart (i.e less filters).

Thanks for any explanation.

[rwunderlich · Accepted solution]

The online help for Chart Types / Chart Properties Dimensions: contains the following guidance on number of Dimensions per chart Type.

"A chart can display one or more dimensions. The upper limit depends on the actual chart type, the complexity of the data and the available memory. Pie, line and scatter charts can display a maximum of two dimensions, bar, block and grid charts three. Radar and funnel charts can only display a single dimension, and gauge charts use no dimensions at all. Further dimensions are ignored."

https://help.qlik.com/en-US/qlikview/November2017/Subsystems/Client/Content/Bar_Chart.htm

The Doc says "Further Dimensions are ignored" which is true when there are multiple values for the upper Dimensions.  Line charts can use a maximum of 2 dimensions so the third dimension is ignored and has no effect on the rendering of the chart. Dim1 is used as the x-axis and Dim2 generates multiple lines for Dim2 values. Until...there is only one value for Dim1 one and then Dim2 becomes the x-axis and Dim3 generates multiple lines.

I'll admit this dynamic promotion/drill behavior is entirely new to me and I've been using QV for 12 years.  Of course I only ever used 2 dimensions on my line chart because I "knew the dimensions beyond 2 were ignored". Hah.

Perhaps someone else on the forum has some insight as to whether this is an intentional feature or a bug.

To offer some relaxation about your original question, there is documentation about how many dimensions are allowed and what they do. Yes, they are order dependent. In the case of a line chart, Dim1 being the x-axis and Dim2 generating individual lines.  What's surprising to both me and you is the automatic promotion of Dims when there is only one value.

-Rob

http://masterssummit.com

http://qlikviewcookbook.com

[cthomas2]

Thank you, all my googling couldn't get me to the page you linked (I can't navigate Qlik's site, it doesn't make sense to me unfortunately). I will have to bookmark that page.

Good to know the promotion of the 2nd dimension to X axis doesn't make sense to someone else either!

[cthomas2]

Ok since you explained the 3rd+ dimensions are ignored, I removed my 3rd dimension entirely, and now when I filter down to a single timestamp, it remains correct. Perhaps it is a feature? Because I can see how just 1 value of the same stat you see in the larger view may not be useful... just in my case the result is messy because I have a lot of databases

Thanks again!