/**
* Test geolib::expand().
* This test isn't yet working for edge cases,
* expanding to the original precision or to the minimum precision.
* Perhaps those expansions don't make much sense.
*
* @dataProvider geohashProvider
* @param string $geohash
*/
public function testCircle($geohash)
{
$circle = new geohash_circle($geohash);
$center = geohash::decode($geohash);
$last_radius = 0;
// test all precisions up to 0
do {
$radius = $circle->max_radius() / EARTH_RADIUS;
$circle->expand($geohash, $precision);
// the center point should be in the set
$this->assertTrue($circle->contains($center));
// the following tests only work for points away from the poles where radiuses expand usefully
if ($radius > 0) {
$this->assertGreaterThan($last_radius, $radius);
// all points box size x 1 distance from the center should be in the set
$this->assertTrue($circle->contains(new geopoint(min($center->latitude + $radius, 90), self::normalize_longitude($center->longitude + $radius))));
$this->assertTrue($circle->contains(new geopoint(min($center->latitude + $radius, 90), self::normalize_longitude($center->longitude - $radius))));
$this->assertTrue($circle->contains(new geopoint(max($center->latitude - $radius, -90), self::normalize_longitude($center->longitude + $radius))));
$this->assertTrue($circle->contains(new geopoint(max($center->latitude - $radius, -90), self::normalize_longitude($center->longitude - $radius))));
// at least one point box size x 2 distance from the center should be outside the set
/*
$this->assertFalse($circle->contains(new geopoint(min($center->latitude + $radius*2, 90), $center->longitude + $radius*2)) &&
$circle->contains(new geopoint(min($center->latitude + $radius*2, 90), $center->longitude - $radius*2)) &&
$circle->contains(new geopoint(max($center->latitude - $radius*2, -90), $center->longitude + $radius*2)) &&
$circle->contains(new geopoint(max($center->latitude - $radius*2, -90), $center->longitude - $radius*2)));
*/
$last_radius = $radius;
}
} while ($circle->expand());
}
/**
* Increase the size the of the circle.
* @param int $amount
* @return boolean success|failure
*/
public function expand($amount = 1)
{
if ($this->precision == 1) {
// currently unwilling to expand to cover the entire globe
return false;
}
$this->precision = max($this->precision - $amount, 1);
// shrink the geohash, grow the box
$center = substr($this->center_geohash, 0, $this->precision);
$box = geohash::decode_box($center);
$dlat = $box->north - $box->south;
$dlon = $box->east - $box->west;
$set = new geohash_set();
$set->add($center);
$quadrant = geohash::quadrant($this->center_geohash, $this->precision);
if ($quadrant == geohash::northeast || $quadrant == geohash::northwest) {
// north side
$north = geohash::neighbor($center, geohash::north);
if ($north) {
$set->add_set(geohash::halve($north, geohash::south));
if ($quadrant == geohash::northeast) {
$set->add_set(geohash::quarter(geohash::neighbor($north, geohash::east), geohash::southwest));
} else {
// northwest
$set->add_set(geohash::quarter(geohash::neighbor($north, geohash::west), geohash::southeast));
}
$box->north += $dlat / 2;
}
} else {
// south side
$south = geohash::neighbor($center, geohash::south);
if ($south) {
$set->add_set(geohash::halve($south, geohash::north));
if ($quadrant == geohash::southeast) {
$set->add_set(geohash::quarter(geohash::neighbor($south, geohash::east), geohash::northwest));
} else {
// southwest
$set->add_set(geohash::quarter(geohash::neighbor($south, geohash::west), geohash::northeast));
}
$box->south -= $dlat / 2;
}
}
if ($quadrant == geohash::northeast || $quadrant == geohash::southeast) {
// east side
$set->add_set(geohash::halve(geohash::neighbor($center, geohash::east), geohash::west));
$box->east += $dlon / 2;
} else {
// west side
$set->add_set(geohash::halve(geohash::neighbor($center, geohash::west), geohash::east));
$box->west -= $dlon / 2;
}
$this->geohash_set = $set;
$this->max_radius = min($this->center->distance_to_longitude($box->east), $this->center->distance_to_longitude($box->west));
if ($box->north < 90) {
$this->max_radius = min($this->center->distance_to_latitude(min($box->north, 90)), $this->max_radius);
}
if ($box->south > -90) {
$this->max_radius = min($this->center->distance_to_latitude(max($box->south, -90)), $this->max_radius);
}
return true;
}
