/**
* Given an object or a string, return a Geometry
*
* @param mixed $input The GeoJSON string or object
*
* @return object Geometry
*/
public function read($input)
{
if (is_string($input)) {
$input = json_decode($input);
}
if (!is_object($input)) {
throw new Exception('Invalid JSON');
}
if (!is_string($input->type)) {
throw new Exception('Invalid JSON');
}
// Check to see if it's a FeatureCollection
if ($input->type == 'FeatureCollection') {
$geoms = array();
foreach ($input->features as $feature) {
$geoms[] = $this->read($feature);
}
return GeoPHP::geometryReduce($geoms);
}
// Check to see if it's a Feature
if ($input->type == 'Feature') {
return $this->read($input->geometry);
}
// It's a geometry - process it
return $this->objToGeom($input);
}
public function centroid()
{
if ($this->isEmpty()) {
return NULL;
}
if ($this->geos()) {
return GeoPHP::geosToGeometry($this->geos()->centroid());
}
$exterior_ring = $this->components[0];
$pts = $exterior_ring->getComponents();
$c = count($pts);
if ((int) $c == '0') {
return NULL;
}
$cn = array('x' => '0', 'y' => '0');
$a = $this->area(TRUE, TRUE);
// If this is a polygon with no area. Just return the first point.
if ($a == 0) {
return $this->exteriorRing()->pointN(1);
}
foreach ($pts as $k => $p) {
$j = ($k + 1) % $c;
$P = $p->getX() * $pts[$j]->getY() - $p->getY() * $pts[$j]->getX();
$cn['x'] = $cn['x'] + ($p->getX() + $pts[$j]->getX()) * $P;
$cn['y'] = $cn['y'] + ($p->getY() + $pts[$j]->getY()) * $P;
}
$cn['x'] = $cn['x'] / (6 * $a);
$cn['y'] = $cn['y'] / (6 * $a);
$centroid = new Point($cn['x'], $cn['y']);
return $centroid;
}
/**
* Serialize geometries into a WKT string.
*
* @param Geometry $geometry
*
* @return string The WKT string representation of the input geometries
*/
public function write(Geometry $geometry)
{
// If geos is installed, then we take a shortcut and let it write the WKT
if (GeoPHP::geosInstalled()) {
$writer = new GEOSWKTWriter();
$writer->setTrim(TRUE);
return $writer->write($geometry->geos());
}
if ($geometry->isEmpty()) {
return strtoupper($geometry->geometryType()) . ' EMPTY';
} else {
if ($data = $this->extractData($geometry)) {
return strtoupper($geometry->geometryType()) . ' (' . $data . ')';
}
}
}
protected function geomFromXML()
{
$geometries = array();
$geometries = array_merge($geometries, $this->parsePoints());
$geometries = array_merge($geometries, $this->parseLines());
$geometries = array_merge($geometries, $this->parsePolygons());
$geometries = array_merge($geometries, $this->parseBoxes());
$geometries = array_merge($geometries, $this->parseCircles());
if (empty($geometries)) {
throw new Exception("Invalid / Empty GeoRSS");
}
return GeoPHP::geometryReduce($geometries);
}
public function boundary()
{
if ($this->isEmpty()) {
return new LineString();
}
if ($this->geos()) {
return $this->geos()->boundary();
}
$components_boundaries = array();
foreach ($this->components as $component) {
$components_boundaries[] = $component->boundary();
}
return GeoPHP::geometryReduce($components_boundaries);
}
public function simplify($tolerance, $preserveTopology = FALSE)
{
if ($this->geos()) {
return GeoPHP::geosToGeometry($this->geos()->simplify($tolerance, $preserveTopology));
}
}
static function detectFormat(&$input)
{
$mem = fopen('php://memory', 'r+');
fwrite($mem, $input, 11);
// Write 11 bytes - we can detect the vast majority of formats in the first 11 bytes
fseek($mem, 0);
$bytes = unpack("c*", fread($mem, 11));
// If bytes is empty, then we were passed empty input
if (empty($bytes)) {
return FALSE;
}
// First char is a tab, space or carriage-return. trim it and try again
if ($bytes[1] == 9 || $bytes[1] == 10 || $bytes[1] == 32) {
$ltinput = ltrim($input);
return GeoPHP::detectFormat($ltinput);
}
// Detect WKB or EWKB -- first byte is 1 (little endian indicator)
if ($bytes[1] == 1) {
// If SRID byte is TRUE (1), it's EWKB
if ($bytes[5]) {
return 'ewkb';
} else {
return 'wkb';
}
}
// Detect HEX encoded WKB or EWKB (PostGIS format) -- first byte is 48, second byte is 49 (hex '01' => first-byte = 1)
if ($bytes[1] == 48 && $bytes[2] == 49) {
// The shortest possible WKB string (LINESTRING EMPTY) is 18 hex-chars (9 encoded bytes) long
// This differentiates it from a geohash, which is always shorter than 18 characters.
if (strlen($input) >= 18) {
//@@TODO: Differentiate between EWKB and WKB -- check hex-char 10 or 11 (SRID bool indicator at encoded byte 5)
return 'ewkb:1';
}
}
// Detect GeoJSON - first char starts with {
if ($bytes[1] == 123) {
return 'json';
}
// Detect EWKT - first char is S
if ($bytes[1] == 83) {
return 'ewkt';
}
// Detect WKT - first char starts with P (80), L (76), M (77), or G (71)
$wkt_chars = array(80, 76, 77, 71);
if (in_array($bytes[1], $wkt_chars)) {
return 'wkt';
}
// Detect XML -- first char is <
if ($bytes[1] == 60) {
// grab the first 256 characters
$string = substr($input, 0, 256);
if (strpos($string, '<kml') !== FALSE) {
return 'kml';
}
if (strpos($string, '<coordinate') !== FALSE) {
return 'kml';
}
if (strpos($string, '<gpx') !== FALSE) {
return 'gpx';
}
if (strpos($string, '<georss') !== FALSE) {
return 'georss';
}
if (strpos($string, '<rss') !== FALSE) {
return 'georss';
}
if (strpos($string, '<feed') !== FALSE) {
return 'georss';
}
}
// We need an 8 byte string for geohash and unpacked WKB / WKT
fseek($mem, 0);
$string = trim(fread($mem, 8));
// Detect geohash - geohash ONLY contains lowercase chars and numerics
preg_match('/[a-z0-9]+/', $string, $matches);
if ($matches[0] == $string) {
return 'geohash';
}
// What do you get when you cross an elephant with a rhino?
// http://youtu.be/RCBn5J83Poc
return FALSE;
}