ringostarr80 / php5-proj

A php extension for proj.4

php5-proj

A php extension for proj.4

Code example (see: ProjAPI):

<?php  
$pj_merc = pj_init_plus("+proj=merc +ellps=clrk66 +lat_ts=33");  
$pj_latlong = pj_init_plus("+proj=latlong +ellps=clrk66");  
if ($pj_merc !== false && $pj_latlong !== false) {  
	$x = deg2rad(-16);  
	$y = deg2rad(20.25);  
	$transformed = pj_transform($pj_merc, $pj_latlong, 1, 0, $x, $y);  
	print 'latitude: '.$transformed['x'].'<br />';  
	print 'longitude: '.$transformed['y'].'<br />';  
}  
?>

Output:

latitude: -1495284.2114735  
longitude: 1920596.7899174

Code example 2:

<?php  
$pj_merc = pj_init_plus("+proj=merc +ellps=clrk66 +lat_ts=33");  
$pj_latlong = pj_init_plus("+proj=latlong +ellps=clrk66");  
if ($pj_merc !== false && $pj_latlong !== false) {  
	$x = array(deg2rad(-16), deg2rad(-25));  
	$y = array(deg2rad(20.25), deg2rad(13.2));  
	$transformed = pj_transform($pj_merc, $pj_latlong, count($x), 0, $x, $y);  
	print_r($transformed);  
}  
?>

Output:

Array
(
	[x] => Array
		(
			[0] => -1495284.2114735
			[1] => -2336381.5804273
		)

	[y] => Array
		(
			[0] => 1920596.7899174
			[1] => 1236391.9797675
		)

	[z] => Array
		(
			[0] => 0
			[1] => 0
		)

)

API Functions

Basic API

resource pj_init_plus(string definition);
Create a Proj.4 resource coordinate system object from the string definition.

int pj_transform(resource srcdefn, resource dstdefn, int point_count, int point_offset, mixed x, mixed y, mixed z);
Transform the x/y/z points from the source coordinate system to the destination coordinate system.
x, y and z can be double, int or a numeric string.
x, y and z can also be an array of double, int or numeric string values.

void pj_free(resource pj);
Frees all resources associated with pj.

Advanced Functions

boolean pj_is_latlong(resource pj);
Returns true if the passed coordinate system is geographic (proj=latlong).

boolean pj_is_geocent(resource pj);
Returns true if the coordinate system is geocentric (proj=geocent).

string pj_get_def(resource pj, int options);
Returns the PROJ.4 initialization string suitable for use with pj_init_plus() that would produce this coordinate system, but with the definition expanded as much as possible (for instance +init= and +datum= definitions).

resource pj_latlong_from_proj(resource pj_in);
Returns a new coordinate system definition which is the geographic coordinate (lat/long) system underlying pj_in.

Environment Functions

void pj_deallocate_grids();
Frees all resources associated with loaded and cached datum shift grids.

string pj_strerrno(int);
Returns the error text associated with the passed in error code.

int pj_get_errno_ref();
Returns an integer value that can be used for the pj_strerrno(int) function.

string pj_get_release();
Returns an internal string describing the release version.