Proximity Sensor

[MikeSpragg]

I know that SSI have developed a proximity search for US. Has anyone does this for UK? We have DB with Lat/Long and customer wants to shows prospects in/around a particular location/postcode. Anything readily available ?

[rchavez]

Mike:

  First of all, you would have to have the Lat and Long for your Source Location (or Postal Code).

  From there on, it would depend on how you want your Zone to be configured. A Simple attempt would be to create a Rectangular zone. In this case, you just have to find 4 coordinates and query for all records that lie within those for coordiates.

  So, for example, given a point, you calculate the 4 corners of a Square that are X number of Miles away. Then just build a Select statement for any records that lies within that zone.

  Now, if you are looking for a true "within X Miles" circular radius, then you would have to check every record in the DB and see if it is within the Distance to your Point.

I do have a set of SQL functions to determine Distance on Miles or Kilometers. You will however have to create Dynamic SQL Statements to retreive the data including your Comparisson Point.

At the bottom of my document there are some sample ussages of the functions.

Distance Formulas.txt ‏3 KB

[MikeSpragg]

Hi Raul That's great - thanks for sharing - very handy ! I already have the lat/long for every record and comparison point and, also, all UK addresses with PostCode and it's Lat/Long (some 1.7M rows - which load into SLX in 2m 25s) so with those functions I should be able to construct something - many thanks again!