
1. Re: shaded areas of 30 miles on a map
Cristian Vasile Jul 25, 2013 12:31 PM (in response to Louise Prister) 
2. Re: shaded areas of 30 miles on a map
Louise Prister Jul 25, 2013 1:35 PM (in response to Cristian Vasile)Thanks

3. Re: shaded areas of 30 miles on a map
Shawn Wallwork Jul 25, 2013 2:19 PM (in response to Louise Prister)Also, this VizTalk is the culmination of richard.leeke.0's brilliant concentric circles work http://community.tableau.com/thread/117607 (I got to tag along for the fun.)
Shawn

4. Re: shaded areas of 30 miles on a map
Louise Prister Jul 26, 2013 6:45 AM (in response to Shawn Wallwork)Thanks Shawn,
I actually looked thru this yesterday. I think I understand how it works.
But I don’t know how to calculate the Latitude and Longitude on a radius around every one of my 7000 vendors.
Is there a formula I can use?
Thank you,
Louise Prister
8659144546

5. Re: shaded areas of 30 miles on a map
Louise Prister Jul 26, 2013 6:46 AM (in response to Shawn Wallwork)Thank you guys.
Can you give me a hint of how to calculate the Latitude and Longitude on a radius around every one of my 7000 vendors.
Is there a formula I can use?

6. Re: Re: shaded areas of 30 miles on a map
Cristian Vasile Jul 26, 2013 8:36 AM (in response to Louise Prister)Louise,
what exactly do you want to achieve? mockup something and please publish here because i feel that it's a drift of initial question.
http://bluemm.blogspot.com/2007/01/excelformulatocalculatedistance.html
http://kb.tableausoftware.com/articles/knowledgebase/calculatingdistance
Thank you.
Regards,
Cristian.

7. Re: Re: shaded areas of 30 miles on a map
Shawn Wallwork Jul 26, 2013 8:35 AM (in response to Louise Prister) 
8. Re: shaded areas of 30 miles on a map
Louise Prister Jul 26, 2013 8:41 AM (in response to Cristian Vasile)I have a table of 7000 + vendors that perform services for the company all around US.
And I need to draw a map with 30 miles diameter circles around their address, to know their coverage area – they won’t drive farther than 30 miles.
So, I have Lat and Lon in my table for every address.
Based on the presentation the gentleman places on forum (thank him very much) I need to calculate those 360 lat and lon to draw those circles for every vendor (please correct me if I’m wrong) (Also, I’m not sure if this is the best way of doing it, and afraid that this would take me forever to run the report. )
And I do not know the formula how to calculate those 360 lat and lon.
I’m new to Tableau  started to look at it just 2 days ago. So any of your help would be appreciated.
Thank you,
Louise Prister
8659144546

9. Re: shaded areas of 30 miles on a map
Cristian Vasile Jul 26, 2013 8:47 AM (in response to Louise Prister)Louise,
I will try a fast solution for your request, i am sure Shawn will try also something, so i hope to deliver an example asap.
Regards,
Cristian.

10. Re: Re: shaded areas of 30 miles on a map
Shawn Wallwork Jul 26, 2013 8:56 AM (in response to Louise Prister)The formula is in that KB article Cristian linked to. As to performance, I agree 7,000 on one map will probably slow things down to a crawl.
Shawn

11. Re: shaded areas of 30 miles on a map
Louise Prister Jul 26, 2013 9:22 AM (in response to Cristian Vasile)That would be great!
Thank you so much.
Louise Prister
8659144546

12. Re: Re: shaded areas of 30 miles on a map
Cristian Vasile Jul 26, 2013 12:24 PM (in response to Louise Prister)Louise,
Please find a fast mockup, was done in a rush... The viz is based on the idea of drawing 360 small dots around each vendor HQ. You should read the formulas in sheet1 to understand how to compute outside Tableau each lat&long for yours 7K vendors X 360 positions. All units are European/metric. Radius = 50Km ~ 30Mi
Hope this helps.
Regards,
Cristian

Copy of circles_rl.xls 144.5 KB

Book20.twb.zip 27.2 KB


13. Re: Re: shaded areas of 30 miles on a map
Louise Prister Jul 26, 2013 12:36 PM (in response to Cristian Vasile)Thanks Cristian, but I can't find a formula. Can you please tell me where can i find it, please.

14. Re: shaded areas of 30 miles on a map
Cristian Vasile Jul 26, 2013 12:46 PM (in response to Louise Prister)on sheet1, file Copy of circles_rl.xls
Circle_Latitude= DEGREES(ASIN(SIN(RADIANS(Locations!B$2))*COS((distance_in_Km)/6371) + COS(RADIANS(Locations!B$2))*SIN((distance_in_Km)/6371) * COS(RADIANS(Circle!A2))) )
Circle_Longitude= DEGREES(RADIANS( Locations!C$2 ) + ATAN2(COS((distance_in_Km)/6371)SIN(RADIANS( Locations!B$2 ))*SIN(RADIANS( Sheet1!B2 )), SIN(RADIANS(Circle!A2))*SIN((distance_in_Km)/6371)*COS(RADIANS( Locations!B$2 ))) )
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Regards,
Cristian.