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_mapped_segments.py

@@ -0,0 +1,60 @@
+# 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.api.alignment
+from ifcopenshell import entity_instance
+from typing import Sequence
+
+
+def __get_curve_segment_count(segment: entity_instance) -> int:
+    """
+    returns the number of IfcCurveSegment that an IfcAlignmentSegment maps to.
+    generally this is a 1 to 1 mapping, with helmert curve being the exception
+    """
+    if segment.DesignParameters.is_a("IfcAlignmentHorizontalSegment"):
+        return 2 if segment.DesignParameters.PredefinedType == "HELMERTCURVE" else 1
+    elif segment.DesignParameters.is_a("IfcAlignmentVerticalSegment"):
+        return 1
+    elif segment.DesignParameters.is_a("IfcAlignmentCantSegment"):
+        return 2 if segment.DesignParameters.PredefinedType == "HELMERTCURVE" else 1
+
+
+def _get_mapped_segments(file: ifcopenshell.file, layout_segment: entity_instance) -> Sequence[entity_instance]:
+    """
+    Finds the IfcCurveSegment related to segment
+    """
+    expected_type = "IfcAlignmentSegment"
+    if not layout_segment.is_a(expected_type):
+        raise TypeError(f"Expected to see type '{expected_type}', instead received '{layout_segment.is_a()}'.")
+
+    layout = layout_segment.Nests[0].RelatingObject
+    alignment = ifcopenshell.api.alignment.get_alignment(layout)
+    curve = ifcopenshell.api.alignment.get_curve(alignment)
+
+    index = 0
+    for seg in layout.IsNestedBy[0].RelatedObjects:
+        index += __get_curve_segment_count(seg)
+        if seg == layout_segment:
+            break
+
+    segment_count = __get_curve_segment_count(layout_segment)
+    if segment_count == 1:
+        return (curve.Segments[index - segment_count], None)
+    else:
+        return (curve.Segments[index - segment_count], curve.Segment[index])