UTM Spatial References Module¶
This module is one of a suite of modules which provide handling of different spatial reference notation systems, in this case the Universal Transverse Mercator system. Two variants are supported based on different underlying projections, one being WGS84 / UTM zone 30N and the other being ED50 / UTM zone 30N. This module is only required on warehouses which support UTM references for data entry or reporting.
It performs the following tasks:
- Declares the underlying projection’s SRID to be 32630, which is the numeric code given to WGS84 / UTM zone 30N, or to be 23030, which is the numeric code given to the ED50 / UTM zone 30N.
- Provides a method for checking the format of a provided spatial reference.
- Provides conversions for British National Grid references to and from a polygon in the underlying projection.
In order to support additional UTM zones and projections, it is necessary to create additional class files in this module’s helpers folder. The class should be called by a suitable code to store for spatial references of this system and should extend utm_grid. It should implement a single public static function called get_srid which takes no parameters and returns the EPSG code for the UTM grid as looked up on spatialreference.org.