I have not done enough work on Maps, but fear not, I plan to do a lot more in 2019. This tutorial will focus on drawing Arc Maps in Tableau and show a nice curve as opposed to straight lines between points. This should be a quick and fun read, so get ready and enjoy.

﻿Note: As always never choose a data visualisation type and try to fit your data into it, instead, understand your data and choose the best visualization for your data consumers.

## Data

Load the following data into Tableau Desktop / Public.

 Flight End Lat End Long Start Lat Start Long Path London-Berlin 52.520007 13.404954 51.507351 -0.127758 0 London-Berlin 52.520007 13.404954 51.507351 -0.127758 90 London-Dublin 53.349805 -6.26031 51.507351 -0.127758 0 London-Dublin 53.349805 -6.26031 51.507351 -0.127758 90 London-Madrid 40.416775 -3.70379 51.507351 -0.127758 0 London-Madrid 40.416775 -3.70379 51.507351 -0.127758 90 London-Milan 45.465422 9.185924 51.507351 -0.127758 0 London-Milan 45.465422 9.185924 51.507351 -0.127758 90 London-Paris 48.856614 2.352222 51.507351 -0.127758 0 London-Paris 48.856614 2.352222 51.507351 -0.127758 90

## Calculated Fields

With our data set loaded into Tableau, we are going to create the following Calculated Fields:

Path (bin)

• Right-click on Path, go to Create and select Bin…
• Set New field name to Path (bin).
• Set Size of bins to 1.
• Click Ok.

Index

``INDEX()-1``

TC_Start Lat

``WINDOW_MAX(MAX([Start Lat]))``

TC_Start Long

``WINDOW_MAX(MAX([Start Long]))``

TC_End Lat

``WINDOW_MAX(MAX([End Lat]))``

TC_End Long

``WINDOW_MAX(MAX([End Long]))``

TC_Step Size Lat

``([TC_End Lat]-[TC_Start Lat])/90``

TC_Step Size Long

``([TC_End Long]-[TC_Start Long])/90``

TC_Latitude

``````([Index]*[TC_Step Size Lat])+[TC_Start Lat]+
SIN([Index]/29)``````

Right-click on the the object, go to Geographic Role and select Latitude.

TC_Longitude

``[Index]*[TC_Step Size Long]``

Right-click on the the object, go to Geographic Role and select Longitude.

Destination

``TRIM( SPLIT( [Flight], "-", -1 ) )``

Now that we have our Calculated Fields created, let us start creating our Worksheet.

## Worksheet

We are going to build two worksheets and make them overlap each other. So to build our first worksheet:

• Drag TC_Longitude onto Columns.
• Drag TC_Latitude onto Rows.
• In Show Me, select Symbol Map.
• Change the Mark Type to Line.
• Drag Flight onto Color.
• Drag Destination onto Label.
• Drag Path (bin) onto Columns.
• Right-click on the object, ensure that Show Missing Values is checked.
• Drag this object onto Path.
• Right-click on TC_Longitude in Columns, go to Compute Using and select Path (bin).
• Right-click on TC_Latitude in Rows, go to Compute Using and select Path (bin).

If all goes well you should not see the following:

Now adjust the visualisation as you see fit, have some real fun with this, but when I published this the first time, I got the following:

and boom, we are done, there is a little hard coding in the Calculated Fields, so go back and tweak a bit to see what you get. But this is some cool stuff huh…

You can see and interact with my visualisation on Tableau Public at https://public.tableau.com/profile/toan.hoang#!/vizhome/ArcMaps/ArcMaps

## Summary

If you want to learn more about Creating Bespoke Data Visualisations in Tableau, do check out our course on Udemy at https://www.udemy.com/creating-bespoke-data-visualisations-in-tableau and using the coupon code TMWEB2019

A prolific blogger, contributor and freelancer in the Tableau community. A technology enthusiast with a passion for business intelligence, data visualizations and data management. Also, I love debating and talking tech to the early hours, so get in touch.

1. Hey, Toan!
This is awesome man! Beautiful viz my friend!
It will really be nice if you could explain some of the aspects of this viz, especially the data densificattion and the math parts. I can throw the following questions:
1. You duplicated the data to have two rows per route, one for each Path value (0 and 90). Is that the only way? How does that work? Could it be done with one row and using padding with bins? I mean a calculated field that generates 0 or 90 based on some logic, and a bin on top of it.

2. To draw the lines, are you simply drawing a SIN wave across 90 points? How to make sense of this formula: ([Index]*[TC_Step Size Lat])+[TC_Start Lat]+
SIN([Index]/29) used for TC_Latitude? Is the number 29 arbitrary? I tried values less and more and I could see why you chose 29, but what does it mean?

Most of us are lost when it comes to trigonometry in Tableau, not because of Trigo itself, but how those formulas are relevant within a Tableau challenge.
Thanks
Ashraf

• Hi Ashraf,