[Feature] Nearest point on polygon from a point

[sumit2201]

No description provided.

[sumit2201]

With Reference to this requirement
https://stackoverflow.com/questions/56048358/using-php-find-nearest-point-in-polygon-from-a-given-point

I want to find nearest point on polygon(An Area on map) from a particular point (Lat, Long).
Can you please help if this library support such functionality or is it achievable by any means in PHP only>

[acidjazz]

@sumit2201 did you ever happen to find this elsewhere?

[sumit2201]

I could not find any PHP solution for this, and my requirement was GIS centric, so I used postGIS queries to find nearest point. I used ST_ClosestPoint of postGIS/postgresql.
@acidjazz We can close this requirement if you want

[acidjazz]

@sumit2201 Lets keep it open since its a sweet feature, last question, did St_CLosestPoint give you the actual point that was found on the Line? and not only the distance?

[mjaschen]

Hi,

is such an implemention available in source code in any language and with a permissive license? If that's the case, I'd be happy to translate it to PHP and integrate it into phpgeo.

[acidjazz]

@mjaschen I think you're pretty darn close already.

You have your PerpendicularDistance utility which I use in combination with polygon getSegments() to find the closest segment

foreach ($this->polygon->getSegments() as $line) {
    if ($line->getLength($haversine) !== 0.0) {
        $polyline = new Polyline();
        $polyline->addPoint($line->getPoint1());
        $polyline->addPoint($line->getPoint2());
        $distances[] = [
           'value' => $perp->getPerpendicularDistance($this->point, $line),
           'geometry' => json_decode($formatter->format($polyline), true),
        ];
    }
}
usort($distances, function($a, $b) {
    return $a['value'] - $b['value'];
});

return reset($distance)

All that I think is missing from this @mjaschen is getting that Utility to tell us WHERE on the line did you find was the closest?