.. index:: single: crs_projections
.. _crs_projections/0:

.. rst-class:: right

**object**

``crs_projections``
===================

Coordinate reference systems and common transformations for 2D and 3D WGS84 geodetic coordinates, Web Mercator, World Mercator, ECEF, local ENU tangent-plane, Lambert azimuthal equal-area, and UTM coordinates.

| **Availability:** 
|    ``logtalk_load(crs_projections(loader))``

| **Author:** Paulo Moura
| **Version:** 1:0:0
| **Date:** 2026-05-10

| **Compilation flags:**
|    ``static, context_switching_calls``


| **Implements:**
|    ``public`` :ref:`crs_projections_protocol <crs_projections_protocol/0>`
| **Uses:**
|    :ref:`geospatial <geospatial/0>`

| **Remarks:**

   - Geographic coordinates: WGS84 coordinates are represented as ``geographic(Latitude,Longitude)`` in degrees.
   - 3D geodetic coordinates: WGS84 3D coordinates are represented as ``geographic(Latitude,Longitude,EllipsoidalHeight)`` using degrees for angular axes and meters for height.
   - Projected coordinates: Web Mercator, World Mercator, and Lambert azimuthal equal-area coordinates are represented as meter-based ``projected(X,Y)`` pairs. UTM coordinates are represented as ``grid(Easting,Northing)`` pairs.
   - Geocentric coordinates: ECEF coordinates are represented as ``ecef(X,Y,Z)`` triples in meters.
   - Local tangent-plane coordinates: ENU coordinates are represented as ``enu(East,North,Up)`` triples in meters relative to an origin coordinate.
   - UTM coverage: UTM helpers and transformations only succeed for latitudes in the ``[-80.0,84.0[`` range.

| **Inherited public predicates:**
|     :ref:`crs_projections_protocol/0::crs_dimensions/2`  :ref:`crs_projections_protocol/0::crs_epsg/2`  :ref:`crs_projections_protocol/0::crs_kind/2`  :ref:`crs_projections_protocol/0::crs_name/2`  :ref:`crs_projections_protocol/0::crs_units/2`  :ref:`crs_projections_protocol/0::epsg_crs/2`  :ref:`crs_projections_protocol/0::lambert_azimuthal_equal_area/3`  :ref:`crs_projections_protocol/0::lambert_azimuthal_equal_area_inverse/3`  :ref:`crs_projections_protocol/0::local_tangent_plane/3`  :ref:`crs_projections_protocol/0::local_tangent_plane_inverse/3`  :ref:`crs_projections_protocol/0::transform/4`  :ref:`crs_projections_protocol/0::utm_crs/2`  :ref:`crs_projections_protocol/0::utm_zone/2`  :ref:`crs_projections_protocol/0::valid_coordinate/2`  :ref:`crs_projections_protocol/0::valid_crs/1`  

.. contents::
   :local:
   :backlinks: top

Public predicates
-----------------

(no local declarations; see entity ancestors if any)

Protected predicates
--------------------

(no local declarations; see entity ancestors if any)

Private predicates
------------------

(no local declarations; see entity ancestors if any)

Operators
---------

(none)

.. seealso::

   :ref:`crs_projections_protocol <crs_projections_protocol/0>`, :ref:`geospatial <geospatial/0>`