Polygon Files Structures - Solid Color Maps

Instead of explaining it all, I've attached an example.  This has the datasource and several examples in a packaged workbook.  Note the importance of having all the points in the polygon and the order that those points are supposed to be connected.

Marc,

I would like to do domething similar, but instead show a map of New York state, with polygon shapes for each zipcode. Can you share what you used as your source of the lat/long numbers so I can recreate on a state level?

Dan,

The Packaged Workbook that Marc attached can be unpackaged to reveal both the data and background images used in the workbook.

To unpackage the file:

1. Right-click the .twbx file in Windows explorer.

2. Select Unpackage.

The resulting folder has a spreadsheet in it called election.xls, which contains an example of how the latitude and longitude values were structured.

However, for convenience, I've attached the MS Excel file below.

Erin,

I do follow as to how the underlying data forms the shape of each state (and how to observe the underlying data). But what I was hoping to do was to recreate this for a single state (New York), and to setup a file that has the lat/long for the counties withing the state.

Thus my question is not how it was done, but rather the SOURCE of the lat/long points that are used. I'm trying to identify where one would get the lat/long values needed to accomplish what I would like to do.

One source for Zip code boundary files is the US census, http://www.census.gov/geo/www/cob/zt_metadata.html

These are actually ZCTA (Zip Code Tabulation Area) boundaries, as Zip codes are delivery routes and do not always correspond exactly to a polygonal area.  See the Census web site for more discussion of the differences.

The census boundary files may be excessively detailed, causing Tableau to spend a long time rendering them.

Hi Dan,

Don't know if this is too late, but zip code boundaries and labels are built into the "Map Options".  Tableau will do it for you.

Mandy

Hi Mandy -

Can you give more guidance on how to access those boundaries and load them such that they can be used to create a thematic map?

SCR

Zip code boundaries are a layer that can be turned on in the Map Options card (View -> Other Cards -> Map Options if it's been turned off).

While you can map polygon data, you cannot create a thematic map based upon the map layers provided.

Hi guys,

I was just about to ask this question, and realized there is a good dicussion going on.

I am a complete newbie to Tableau, but have mapped data in Arcview.  What do I have to fill in polygons here in Tableau - right now, I just want to fil in states.

I know you gave a great example, I just need to be explained the process.  Essentially, what data files do I need to bring over from Arcview and how do I attach the data in Tableau?

Many thanks for your insight,

Brock

All,

Great posts. It appears I am missing the step of how to convert the census file format (Arc/info Arcview) into something that I can inport to Tableau (access, xls, etc...) eg. election.xls

Thanks for your help on this.

-Chris

It'd be nice if Tableau could format the files and make them centrally downloadable to each of us, so we don't all independently recreate the wheel. Tracking them down and manipulating is the hard part of this process.

Chris (Cush) - can you explain how you crunched the numbers from ASCII and how you got it into Tableau?

I wrote a macro that rearranges the raw data in the 104 ASCII files, merges them together and puts that data into a normalized Access database. Sometime in the next 12 hours I'll upload the .mdb file.