first import
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Bachir Soussi Chiadmi
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GeoPHP is a open-source native PHP library for doing geometry operations. It is written entirely in PHP and
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can therefore run on shared hosts. It can read and write a wide variety of formats: WKT (including EWKT), WKB (including EWKB), GeoJSON,
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KML, GPX, GeoRSS). It works with all Simple-Feature geometries (Point, LineString, Polygon, GeometryCollection etc.)
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and can be used to get centroids, bounding-boxes, area, and a wide variety of other useful information.
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geoPHP also helpfully wraps the GEOS php extension so that applications can get a transparent performance
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increase when GEOS is installed on the server. When GEOS is installed, geoPHP also becomes
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fully compliant with the OpenGIS® Implementation Standard for Geographic information. With GEOS you get the
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full-set of openGIS functions in PHP like Union, IsWithin, Touches etc. This means that applications
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get a useful "core-set" of geometry operations that work in all environments, and an "extended-set"of operations
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for environments that have GEOS installed.
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See the 'getting started' section below for references and examples of everything that geoPHP can do.
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This project is currently looking for co-maintainers. If you think you can help out, please send me a
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message. Forks are also welcome, please issue pull requests and I will merge them into the main branch.
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Getting Started
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-----------------------
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* The lastest stable version can always be downloaded at: <https://github.com/downloads/phayes/geoPHP/geoPHP.tar.gz>
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* Read the API Reference at: <https://github.com/phayes/geoPHP/wiki/API-Reference>
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* Examples
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* Using geoPHP as a GIS format converter: <http://github.com/phayes/geoPHP/wiki/Example-format-converter>
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* Other Interesting Links:
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* Learn about GEOS integration at: <https://github.com/phayes/geoPHP/wiki/GEOS>
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Example usage
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-------------------------------------------------
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```php
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<?php
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include_once('geoPHP.inc');
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// Polygon WKT example
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$polygon = geoPHP::load('POLYGON((1 1,5 1,5 5,1 5,1 1),(2 2,2 3,3 3,3 2,2 2))','wkt');
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$area = $polygon->getArea();
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$centroid = $polygon->getCentroid();
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$centX = $centroid->getX();
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$centY = $centroid->getY();
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print "This polygon has an area of ".$area." and a centroid with X=".$centX." and Y=".$centY;
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// MultiPoint json example
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print "<br/>";
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$json =
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'{
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"type": "MultiPoint",
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"coordinates": [
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[100.0, 0.0], [101.0, 1.0]
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]
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}';
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$multipoint = geoPHP::load($json, 'json');
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$multipoint_points = $multipoint->getComponents();
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$first_wkt = $multipoint_points[0]->out('wkt');
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print "This multipoint has ".$multipoint->numGeometries()." points. The first point has a wkt representation of ".$first_wkt;
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```
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=======
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More Examples
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-------------------------------------------------
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The Well Known Text (WKT) and Well Known Binary (WKB) support is ideal for integrating with MySQL's or PostGIS's spatial capability.
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Once you have SELECTed your data with `'AsText('geo_field')'` or `'AsBinary('geo_field')'`, you can put it straight into
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geoPHP (can be wkt or wkb, but must be the same as how you extracted it from your database):
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$geom = geoPHP::load($dbRow,'wkt');
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You can collect multiple geometries into one (note that you must use wkt for this):
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$geom = geoPHP::load("GEOMETRYCOLLECTION(".$dbString1.",".$dbString2.")",'wkt');
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Calling get components returns the sub-geometries within a geometry as an array.
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$geom2 = geoPHP::load("GEOMETRYCOLLECTION(LINESTRING(1 1,5 1,5 5,1 5,1 1),LINESTRING(2 2,2 3,3 3,3 2,2 2))");
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$geomComponents = $geom2->getComponents(); //an array of the two linestring geometries
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$linestring1 = $geomComponents[0]->getComponents(); //an array of the first linestring's point geometries
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$linestring2 = $geomComponents[1]->getComponents();
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echo $linestring1[0]->x() . ", " . $linestring1[0]->y(); //outputs '1, 1'
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An alternative is to use the `asArray()` method. Using the above geometry collection of two linestrings,
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$geometryArray = $geom2->asArray();
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echo $geometryArray[0][0][0] . ", " . $geometryArray[0][0][1]; //outputs '1, 1'
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Clearly, more complex analysis is possible.
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echo $geom2->envelope()->area();
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Working with PostGIS
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---------------------
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geoPHP, through it's EWKB adapter, has good integration with postGIS. Here's an example of reading and writing postGIS geometries
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```php
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<?php
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include_once('geoPHP.inc');
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$host = 'localhost';
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$database = 'phayes';
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$table = 'test';
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$column = 'geom';
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$user = 'phayes';
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$pass = 'supersecret';
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$connection = pg_connect("host=$host dbname=$database user=$user password=$pass");
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// Working with PostGIS and Extended-WKB
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// ----------------------------
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// Using asBinary and GeomFromWKB in PostGIS
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$result = pg_fetch_all(pg_query($connection, "SELECT asBinary($column) as geom FROM $table"));
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foreach ($result as $item) {
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$wkb = pg_unescape_bytea($item['geom']); // Make sure to unescape the hex blob
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$geom = geoPHP::load($wkb, 'ewkb'); // We now a full geoPHP Geometry object
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// Let's insert it back into the database
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$insert_string = pg_escape_bytea($geom->out('ewkb'));
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pg_query($connection, "INSERT INTO $table ($column) values (GeomFromWKB('$insert_string'))");
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}
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// Using a direct SELECT and INSERTs in PostGIS without using wrapping functions
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$result = pg_fetch_all(pg_query($connection, "SELECT $column as geom FROM $table"));
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foreach ($result as $item) {
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$wkb = pack('H*',$item['geom']); // Unpacking the hex blob
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$geom = geoPHP::load($wkb, 'ewkb'); // We now have a geoPHP Geometry
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// To insert directly into postGIS we need to unpack the WKB
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$unpacked = unpack('H*', $geom->out('ewkb'));
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$insert_string = $unpacked[1];
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pg_query($connection, "INSERT INTO $table ($column) values ('$insert_string')");
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}
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```
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Credit
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-------------------------------------------------
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Maintainer: Patrick Hayes
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This library was written entirely in my free time as a volunteer. If you find it really useful, please consider making a donation by [clicking here] (https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=geomemes%40gmail%2ecom&lc=US&item_name=Patrick%20Hayes%20-%20geoPHP&no_note=0¤cy_code=USD&bn=PP%2dDonationsBF%3abtn_donate_LG%2egif%3aNonHostedGuest).
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Additional Contributors:
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* GeoMemes Research <http://www.geomemes.com>
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* Arnaud Renevier (gisconverter.php) <https://github.com/arenevier/gisconverter.php>
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* Dave Tarc <https://github.com/dtarc>
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* Elliott Hunston (documentation) <https://github.com/ejh>
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This library is open-source and dual-licensed under both the Modified BSD License and GPLv2. Either license may be used at your option.
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