[Proj] Coordinate within an area ?

Roger Oberholtzer roger at opq.se
Tue Mar 30 07:05:13 EST 2010

On Tue, 2010-03-30 at 04:18 -0700, Hamish wrote:
> Martin Raspaud wrote:
> > Is there a way to know if a point defined by its lon/lat
> > coordinates is within
> > an area which corners are given in lon/lats also ?
> yes, there are many methods to do this. try a web search
> for "point in polygon". if it is corners of a box, it's trivial..

As lat/longs and not meters? On a non-flat surface? Isn't it more
complicated with lat/long for this? I would think you should convert the
values to northings/eastings and do the test on that data. Then it could
perhaps be a bounding box test.

My next questions would be: (1) how accurate does it need to be? and (2)
If it is done everywhere in the world, what projection to use to reduce
error? I would think SMHI would be working in and near Sweden, and would
be ok with SWEREF99.

Roger Oberholtzer

OPQ Systems / Ramböll RST

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SE-104 62 Stockholm, Sweden

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