[geos-devel] Looking for the closest point

[Rémi Cura]

Hey,
if you have access to sql,
you don't need geos.

You could simply convert line to point then order by distance and get the
closest.
Using postgis it would be quiet easy.
You lines appears to be big, so a simple euclidian distance may give you
wrong result, you would need a geographical distance.

Cheers,

Rémi-C


2014-03-03 10:35 GMT+01:00 Paul Meems <bontepaarden at gmail.com>:

> Hi List,
>
> We use with MapWinGIS (C++ ActiveX control) GDAL with GEOS.
>
> I've got a linestring (stream) and need to know the closest point at that
> stream from a specific location.
> What I need is the index of the point in the stream and the distance from
> the location to that point.
>
> We currently have a custom GetClosestPoint method which is not using GEOS,
> but that is not working when a long linestring is close to the location but
> the points are far away.
> For example my line has two points, starts in Amsterdam and ends in Paris.
> My location is near Antwerp.
>
> Does GEOS have a better method for this? I did searched using Google and
> found several methods/pages but I'm not sure what to use.
> I also want to make it a generic method that will work with all types of
> lines and polygons.
>
> Any advice would be much appreciated.
>
> Thanks,
>
> Paul
>
>  *Paul Meems *
> Release manager, configuration manager
> and forum moderator of MapWindow GIS.
> www.mapwindow.org
>
> Owner of MapWindow.nl - Support for
> Dutch speaking users.
> www.mapwindow.nl
>
>
>
> *Join us at the MapWindow GIS Conference 2014
> <http://geogis.detek.unideb.hu/TKonferencia/2014/>, in Debrecen Hungary*
>
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