Alignment api update (#6817)

* Some basic COGO survey points functions

* Update alignment api

Includes defining alignment segment by segment, automatic geometry definitions, and automatric stationing and referents

* Fixes bonsai import alignment from csv

* Adds DMS angle conversion functions to COGO api

* Updated per @civilx64 review comments

* Fixes problem with segment representations

* Fixes problem with segment transition codes

* Allows for compound vertical and horizontal curves

* Implements callbacks for referent naming

* Renames angle_from_bearing to bearing2dd for consistency with ifcopenshell.util.geolocation.dms2dd. Removes angle_from_dms because it duplicates dms2dd

* Documents register_referent_name_callback

* Fixes all sorts of problems with Cant/SegRefCurve implementation

* refactor referent unit tests to use a fixture for test setup

* lint with black

---------

Co-authored-by: Scott Lecher <civilx64@gmail.com>

src/ifcopenshell-python/ifcopenshell/api/alignment/get_layout_curve.py

@@ -0,0 +1,55 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2025 Thomas Krijnen <thomas@aecgeeks.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import ifcopenshell
+import ifcopenshell.util
+from ifcopenshell import entity_instance
+
+import ifcopenshell.util.representation
+
+
+def get_layout_curve(layout: entity_instance) -> entity_instance:
+    """
+    Returns the representation curve for the layout. This will be an IfcCompositeCurve, IfcGradientCurve, or IfcSegmentReferenceCurve
+    for IfcAlignmentHorizontal, IfcAlignmentVertical, or IfcAlignmentCant, respectively.
+
+    :param layout: An alignment layout
+    :return: The geometric representation curve
+
+    Example:
+
+    .. code:: python
+        alignment = model.by_type("IfcAlignment")[0]
+        layout = ifcopenshell.api.get_horizontal_layout(alignment)
+        composite_curve = ifcopenshell.api.alignment.get_layout_curve(layout)
+    """
+    alignment = ifcopenshell.api.alignment.get_alignment(layout)
+
+    curve = ifcopenshell.api.alignment.get_curve(alignment)
+    if layout.is_a("IfcAlignmentHorizontal"):
+        # Layout is horizontal so get the IfcCompositeCurve
+        if curve.is_a("IfcGradientCurve"):
+            curve = curve.BaseCurve
+        elif curve.is_a("IfcSegmentedReferenceCurve"):
+            curve = curve.BaseCurve.BaseCurve
+    elif layout.is_a("IfcAlignmentVertical"):
+        # Layout is vertical so get the IfcGradientCurve
+        if curve.is_a("IfcSegmentedReferenceCurve"):
+            curve = curve.BaseCurve
+
+    return curve