9 Replies Latest reply on Sep 25, 2019 8:09 PM by Soumitra Godbole

# Plotting Regions with Lat/Long in a Calc Field

In my data I have a field for region.

Rather than adding Latitude & Longitude to an Excel file or adding it to my database, can I create a calculated field with the latitude and longitude and then plot them on a map?  Looking to plot a circle on a map representing a region.

For instance,

Regions:

MDW   Lat=  35,  Long -110

BAC  Lat= 45, Long -22

AVC  Lat=68, Long -7

Appreciate if you could show the solution in a sample workbook with these regions.  Again, not looking to have the Latitude/Longitude data in a Excel file but just in a calculated field.  Not sure it's relevant, but as a side note, some of my regions fall inside the United States and some fall outside it.

Thanks,

Marc

• ###### 1. Re: Plotting Regions with Lat/Long in a Calc Field

Well, you can't have a calculated field without having a field to base the calculation on.

You need 2 fields.  Can't do it in one, as you need lat & long to be separate columns.

So, for latitude:

IF [Region]='MDW'

THEN 35

ELSEIF [Region]='BAC'

THEN 45

ELSEIF [Region]='AVC'

THEN 68

END

And something similar for Longitude.  Then you set the geo role for each field to the corresponding value.

You'll end up with a point on a map.  Is that what you're looking for?

• ###### 2. Re: Plotting Regions with Lat/Long in a Calc Field

good morning

in 2019.2 Makepoint was introduced - it can be nested in other calculation or used as a stand alone to  create a single point

it would return this for your first point as an example

Jim

If this posts assists in resolving the question, please mark it helpful or as the 'correct answer' if it resolves the question. This will help other users find the same answer/resolution.  Thank you.

• ###### 3. Re: Plotting Regions with Lat/Long in a Calc Field

Hey Jim,

Thank for the reply.  I'm curious about this MAKEPOINT calculation.  How would this work with multiple points on a map?  Let's say I have three regions (in my actual data set I have many, many more).   How would this work?  Getting an error message (below) when putting in more than one region into the calc field.

• ###### 4. Re: Plotting Regions with Lat/Long in a Calc Field

looks like you are not up-to-date with 2019.2 (at least )   -

these 3 were introduced at that time

if you have only 3 I would create a case statement and load them that way

you can use them in any nested calc or LOD but that said you need to upgrade

Jim

• ###### 5. Re: Plotting Regions with Lat/Long in a Calc Field

Thanks, Jim.  I upgraded my version of Tableau and was able to get the MAKEPOINT function and render the points on the map.

Many thanks,

Marc

• ###### 6. Re: Plotting Regions with Lat/Long in a Calc Field

Great - they are good additions - Distance makes it easier to calculate the "Crow fly" distance between 2 points

Jim

• ###### 7. Re: Plotting Regions with Lat/Long in a Calc Field

Hey Michael,

I created these two calc fields, and changed one of the geo roles to Longitude and one to Latitude.  However I'm not able to get the points to render on a map.

When I drag the newly created calc fields to rows or the level of detail shelf, "SUM" is showing before the name of the field.

Could you show me an example workbook and/or expand your answer on how to do this?

Thanks,

Marc

• ###### 8. Re: Plotting Regions with Lat/Long in a Calc Field

Nuts, I can't implement this "MAKEPOINT" solution because my version of server is older than 2019.2.  I'll have to find another solution.

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• ###### 9. Re: Plotting Regions with Lat/Long in a Calc Field

Hello again Marc,

Hope you're having a wonderful day. The battle isn't lost as yet and here is an interesting and

simple solution using an earlier version 10.5 (prior to 2019.2). I wish to Make a Point  without having

to use the function Makepoint !

Please note that  the current solution provided above works perfectly using the newer version (2019.2 &

2019.3). The following solution is for prior versions and the explanation is rated U (for all audiences).

Also the advantage of this method is that you have no restrictions on the number of points as long as

the dummy field has greater than or equal to the number of points you need to show on the map.

Here is the trick, using the simple superstore workbook (directly connecting to the excel workbook).

I looked for a dummy field you probably may not need to use as a filter on the dashboard and found

"Shipping Mode". Really, you can use any random field that is of little importance and create this calculated

field. Another option is doing a cross join to an excel file with the Latitude & Longitude data.

Luckily it had more than 3 values (actually 4) so with the following calculated fields you can easily arrive

at the solution and probably do a lot more like varying sizes based on numbers, use Squares or alternate

shapes etc. and add a little color.

Also remember to set the Longitude (Calc) & Latitude (Calc) fields to

Geographic Role as shown below:

The above screenshot is only for Longitude, but you will have to do it for

Latitude as well. Well with all this I regret that I have nothing else to say.

Question:  Is there any catch to this method ?

Answer:     Absolutely! This solution can fall apart if you place the "Ship Mode" field

into the filter shelf. But for the problem, I am assuming you will not need

it . Another option is to replicate and use this datasource for the map.

Hopefully you will have some other id field that you can use to create the above

calculated fields (it does not matter how many IDs you have as your problem only

requires 3 that will be allocated to the 3 Regions and the others will be Null).

The best part about Tableau is that it allows you to come up with completely new ways of

solving problems in addition to the existing ones. Here the importance is given to the idea

and how it is implemented rather than using it as a mere tool to achieve the result i.e. more

like the "Mind over Matter" approach.

I have attached the the twbx file below. I sincerely hope you find this alternate solution useful

in addition to being entertaining and it answers your problem. Also let me know if you have

any questions or would like any changes or further modifications. Best Wishes !

Sincerely,

Soumitra

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