Optimum search with geospatial coordinates

Tod Hansmann plug.org at todandlorna.com
Wed Mar 19 00:39:42 MDT 2014


On 3/18/2014 10:48 PM, S. Dale Morrey wrote:
> It's a severely resource constrained environment.  Think a j2me 
> feature phone as a possible target.
> I get a data file from an external source periodically, but a DB is 
> not an option here, there just isn't enough room for the overhead and 
> that really seems like overkill for something like this.
>
> I can't see the search being frequent enough to warrant more than a 
> few hours of tinkering, but I would like the search to be as snappy as 
> possible.
>
> It can easily be "as the crow flies" so we don't need to be worried 
> about best path, just closest point.
> Anyways thanks for the advice.
>
I wasn't suggesting a database, that's just silly.  I also work in 
resource constrained environments (sometimes as constrained as a PIC18), 
but that doesn't mean I wouldn't setup an in-memory tree of some sort 
(instead of the array/vector) if I needed to do a search a lot of 
times.  Even a linked list could be sorted in various ways. Anyway, if 
it's an array/vector there's really no avoiding checking every single 
item, because there's nothing saying the next item can't have a shorter 
distance result.  It's an easy calculation and all that, but it's still 
going to be O(n) regardless of the approach.

-Tod Hansmann



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