Thanks for the example. I have had similar requests and had been searching for a way to accomplish this.

Great example.  So let me get this straight, there is no Tableau field or function to determine the current zoom right?  I believe your solution is the only way.

Hi Brandy,

This is great, thank you. The breakthrough appears to be setting the size range on the size legend. Once you do that, you can use just a parameter, no calculated fields required. Worked for me in Desktop and Server 8.1. See attached image.

Regards,

Zach

Do you know if this is still valid for Tableau 10.4?  I am stuck on the "Edit Size Legend to use a range" step.

All I see on the size legend is a slider bar with two marks at 1/5 and 2/5 of the way across.  It suggests five possible values but I can't tell if that is really the case..  I used five values just like the example above.

Hi Terence, it still works, you need to select the legend, not the slider. See embedded pictures. Regards, Zach.

Hi,

I ma new to Tableau. Haven't had chance to search for the details, so thinking it may be easier to ask the experts here.  A simple question, it appears to me that tableau makes number of sizes automatically and sometimes you need more steps to show more granularity.  Do I make more steps for the size?

Typo error. I meant to say  How do I make more steps for the size?

Hi Fikri, I don't think you can make more steps for the legend. The sizes are actually continuous and the legend just shows a few different sizes across the range. I think Tableau tries to pick round numbers plus min/max from your data set. It's different with colors, where even with continuous colors you can manually set the number of steps. Regards, Zach.

Is it possible to scale the marks automatically as the map zooms in and out?

For example if I have a column called 'diameter', I would like to make the points on the map 'diameter' kilometers wide (on the map) regardless of my zoom level (as opposed to the default behaviour for the diameter to correspond to a size on the display).

I could do this using a calculation if I could access Tableau's internal variable indicating the map scale (like [km per pixel] or something like that).

Default behaviour (size of point on screen stays the same):

Zoomed in:

Zoomed out:

Desired behaviour (size of point on map stays the same):

Zoomed in:

Zoomed out:

Hi Zach - this request came back 9 months after I tried once:

This time I found that I had to enable the size legend (Analysis > Legends > Size Legend)

This was the missing step.

Thanks for sharing this Brandy Lackey!

Thanks, this is really useful~!!!!

I believe the easier way is to create:

Parameter:

Name: Size

Specs: as Integer Range Min:1 Max: 10 Interval: 1

Calculation:

Name: Size calc

Formula: [Size]   (only the name of the parameter)

Change marks to Shapes

Drop the calculation Size cals on the size icon in marks

Right click parameter, show it and play with it.