README

Parser library for 2D, 3D, and 4D Open Geospatial Consortium (OGC) WKB or PostGIS EWKB spatial object data.

Usage

There are two use patterns for the parser. The value to be parsed can be passed into the constructor, then parse() called on the returned Parser object:

$parser = new Parser($input);

$value = $parser->parse();

If many values need to be parsed, a single Parser instance can be used:

$parser = new Parser();

$value1 = $parser->parse($input1);
$value2 = $parser->parse($input2);

Input value

Encoding

The parser currently supports 3 WKB encodings:

• OGC v1.1
• OGC v1.2
• PostGIS EWKB

Format

The parser supports a number of input formats:

• Binary string (as returned from database or pack('H*', $hexString))
• Bare hexadecimal text string ('01010000003D0AD7A3.....')
• Hexadecimal test string prepended with x, X, 0x, or 0X ('0x01010000003D0AD7A3.....', etc.)

Return

The parser will return an array with the keys type, value, srid, and dimension.

• type string, the uppercase spatial object type (POINT, LINESTRING, etc.) without any dimension.
• value array, contains integer or float values for points, nested arrays containing these based on spatial object type, or empty array for EMPTY geometry.
• srid integer, the SRID if present in EWKB value, null otherwise.
• dimension string, will contain Z, M, or ZM for the respective 3D and 4D objects, null otherwise.

Exceptions

The Reader and Parser will throw exceptions implementing interface CrEOF\Geo\WKB\Exception\ExceptionInterface.

References

• PostGIS EWKB - https://github.com/postgis/postgis/blob/svn-trunk/doc/ZMSgeoms.txt
• OGC Simple Feature Access, Part 1 - http://www.opengeospatial.org/standards/sfa
• OGC Simple Feature Access, Part 2 - http://www.opengeospatial.org/standards/sfs