Module geodesy.projection.utm
Universal Transverse Mercator policy, tagging, and prepared projection.
UTM is implemented as a policy layer over the accepted bounded Transverse Mercator implementation. This module owns zone and hemisphere semantics, standard automatic-zone selection, fixed UTM parameters, tagged coordinates, and explicit prepared-zone operations without duplicating the numerical Transverse Mercator kernel.
Standards
UTM semantics follow the conventional EPSG/IOGP Transverse Mercator operation model and the documented UTM zone/hemisphere policy.
Domain
Zones are 1 through 60. Automatic standard-zone forward projection uses the documented UTM latitude band; explicit prepared-zone operations do not silently reapply automatic zone selection.
Units
UTM easting, northing, false offsets, and supported ellipsoid axes are metre-valued by public policy.
Numerics
Coordinate and factor mathematics delegate to the validated prepared
TransverseMercator implementation; this module adds UTM policy rather
than a second projection algorithm.
Performance
UtmProjection reuses prepared Transverse Mercator state across
repeated operations. Checked numerical paths are allocation-free.
Validation
Policy, parameterization, boundaries, runtime API, PROJ differential behaviour, and GeographicLib oracle cases are covered by dedicated deterministic validators.
See Also
UtmZone, UtmCoordinate, UtmProjection,
TransverseMercator
Date
September 26, 2026
Functions
| Name | Description |
|---|---|
forwardUtm(source, ellipsoid)
|
Automatic UTM forward projection with throwing failure semantics. |
reverseUtm(source, ellipsoid)
|
Reverse a tagged UTM coordinate using its explicit zone and hemisphere. |
tryForwardUtm(source, ellipsoid, result)
|
Project a geographic coordinate using standard automatic UTM zone and hemisphere policy. |
tryReverseUtm(source, ellipsoid, result)
|
Reverse a tagged UTM coordinate using its explicit zone and hemisphere. |
tryStandardUtmZone(source, zone, hemisphere)
|
Select the standard UTM zone and hemisphere for a geographic coordinate. |
Structs
| Name | Description |
|---|---|
UtmCoordinate
|
Projected UTM coordinate carrying zone and north/south false-northing convention for unambiguous reverse projection. |
UtmProjection
|
Prepared Universal Transverse Mercator projection for one explicit zone and north/south false-northing convention. |
UtmZone
|
Strong UTM zone number. |
Enums
| Name | Description |
|---|---|
UtmHemisphere
|
North/south UTM false-northing convention. |