Forum Discussion
Calculate nearest points by geographical coordinates
Hello!
I have two tables. Table "Customers address" with my customers id, latitude and longitude (8 mln rows). And "Shop_table" with my shops id, latitude and longitude (500 rows).
The goal is to find the nearest shop to each of my customers. Fortunatly, I also have column "city" in both my tables. And fortunatly I know the formula to calculate the distance between two geographical points.
I take table "Customers address" and make Table.NestedJoin with "Shop_table" by column "city". And expand it. After that I add column "Distance" with formula distance calculation . Finaly, I make Table.Group and calculate the minimal distance for each customer id.
But it takes a lot of time. Could you advise me a better way?
Dmitry
It seems, I figured how to do it
I made the user function
(reg,x_cast,y_cast)=>
let
Source = Table.SelectRows(shop,each [region]=reg),
formula = Table.AddColumn(Sorce, "Distance", each
6371 * 2 *Number.Asin(Number.Sqrt(Number.Power(Number.Sin((y_cast-[y_shop])*Number.PI/180/2),2)+Number.Cos(y_cast*Number.PI/180)*Number.Cos([y_shop]*Number.PI/180)*Number.Power(Number.Sin((x_cast-[x_shop])*Number.PI/180/2),2)))),
minimum = List.Min(formula[Distance]),
fnl_tbl= Table.SelectRows(formula,each [Custom]=minimum)
in
fnl_tbl
9 Replies
- Greg_Deckler
Community Champion
You might take a look at the new ArcGIS map functionality just released this month for Power BI Desktop.
Unfortunatly, I do not understand how ArcGIS map could solve my task
- ImkeF
How many distinct cities are in your customers table? If significantly less than your number of customers, you could perform the distance calculation based on a list of just the distinct cities of your customers table. Then buffer that result and join back to the customers.
This might be useful to others, I've put togheter a sample PBIX that calculates the closest Shop to Costumers using Dmitry_D's original code. Sample on dropbox here.
