c# 4.0 - Find nearby postcode with a base postcode -

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this reference question: find uk postcodes closest other uk post codes matching post code string

--user wants postcodes nearby b193sh -- postcode  = 'b193sh' -- latitude  = 52.488460 -- longitude = -1.895690  select [housenumber],              [street],              [area],              [postcode],              [latitude],              [longitude],   [dbo].[address]  ([latitude]  between ( 52.488460 - 0.100000 ) , ( 52.488460 + 0.100000 )) ,               ([longitude] between ( -1.895690 - 0.100000 ) , ( -1.895690 + 0.100000 )) order  [postcode] go

executing query, couple of results. question stands difference (meters/miles) +/- 0.100000 lat/lon makes?

should try find close postcodes using first 3 letter of base postcode, i.e., 'b19'?

please see reference question full detail of scenerio.

thanks!

given approximate radius of earth being 6378.1 km.

latitude (and longitude, when along equator)

2 * pi * 6378.1 * 0.1 / 360 = 11.1319 km (4 d.p.)

longitude when along x degrees north or south

for example, when @ 50 degrees north:

2 * pi * 6378.1 * cos(50) * 0.1 / 360 = 7.1554 km (4 d.p.)

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