Filled maps are great. But with Tableau's native background map, it is very difficult to see through the fill to anything in the base layer. And if you crank up the transparency then much of the color encoding of the measure is lost, washed out. Most of you know this has been very high on my personal feature request list. Well Jake Baillie & Ian White at Urban Mapping have come through big time! Here are the results:
You can now easily see the roads, even the side streets, through the fill colors. And in the above screen shot the map 'Washout' level is set to 30% and the filled zips are at 80%! Here's what it looks like with 0% Washout:
A little too strong for my taste, but the point is you now have a full range of contrast choices so you can dial in the appropriate level for your situation. Clients will be better able to figure out where their stores are on the map. And being able to see the block level detail helps imply a scale, especially if you're familiar with the area.
So how did we do this? Well, with Jake's help I hacked the TMS, which is the file that ships with Tableau and sends commands back to Urban Mapping telling them what to display. I should say I hacked a copy of the TMS file. There's no need to mess with the original. The hacked file is attached. All you have to do is download it into your version of this directory:
D:\Shawn\My Tableau Repository\Mapsources
Once it's there, download and open the package workbook I've also attached. Check out the three different 'Filled Map' options I've given you. And definitely play around with the Washout slider.
As long as you keep this TMS file in your Mapsources directory, then these filled background maps will be available to any viz you build.
Unfortunately, there is a catch. (I know there's always a catch.) Currently Tableau doesn't pick up this file when it packages workbooks. So if you send it to a client without the TMS file and instructions I just gave you, the workbook will give an error (big red Xs), not pretty.
After thinking this over I think Richard's idea about picking up the Mapsources folder in the packaged workbook, and then looking at it when Tableau loads, is the best way to go. I posted this idea here. Please consider voting for it.
To everyone else, I hope you like this, and find it useful. Let me know if you have any troubles making it work. Finally, a big shout-out to my good friend and mentor Zen Master Richard Leeke! (Not much of a hack Richard, but a hack all the same; something your tutelage has encouraged me to do. Thanks for all you've given me.)
PS: OK, I did change some of the default settings at the bottom of the page, but that's just personal preference. Feel free to change them back.