Re: Special query type for Spatial DB

hobbit_at_southern_seaweed.com.op says...

> "For example suppose you have a table containing
> the coordinates of points of interest such as motels.
> Given a list of certain locations - eg: highway exists -
> you might need to find the coordinates of the smallest
> rectangle that encloses all the input locations."

Yes, and that's fine. It's a completely different question to that asked by the OP.

He asked about the 10 closest firestations in California.

Now, based on the assumption that there are at least 500 such stations (this is a complete guess BTW) this would involve (500 * 499 * 498 * .... * 491) distance comparisons times the number of combinations of 10 one can get out of 500.... I've confused myself now - something like that anyway.

Basically what you need to know is that this sort of calculation is exp (N) - i.e. that the number of calculations needed increases exponentially with the number of entities being examined. It becomes very messy very quickly, and maths has no magic formula for simply putting the data into a formula and retrieving the numbers.

Paul...

> Pete Brown

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