Implement WCS consideration in XYZ <-> ENH conversions.

src/ifcopenshell-python/ifcopenshell/api/georeference/edit_georeferencing.py

@@ -81,28 +81,32 @@ def edit_georeferencing(
         if not (project := file.by_type("IfcProject")):
             return
         project = project[0]
-        if crs := ifcopenshell.util.element.get_pset(project, "ePSet_ProjectedCRS"):
-            crs = file.by_id(crs["id"])
-            for k, v in projected_crs.items():
-                if k == "Description":
-                    v = file.createIfcText(v)
-                elif k == "Name":
-                    v = file.createIfcLabel(v)
-                else:
-                    v = file.createIfcIdentifier(v)
-            ifcopenshell.api.pset.edit_pset(file, crs, properties=projected_crs)
-        if conversion := ifcopenshell.util.element.get_pset(project, "ePSet_MapConversion"):
-            conversion = file.by_id(conversion["id"])
-            for k, v in coordinate_operation.items():
-                if k in ("XAxisAbscissa", "XAxisOrdinate", "Scale"):
-                    v = file.createIfcReal(v)
-                else:
-                    v = file.createIfcLengthMeasure(v)
-            ifcopenshell.api.pset.edit_pset(file, conversion, properties=coordinate_operation)
+        if projected_crs:
+            if crs := ifcopenshell.util.element.get_pset(project, "ePSet_ProjectedCRS"):
+                crs = file.by_id(crs["id"])
+                for k, v in projected_crs.items():
+                    if k == "Description":
+                        v = file.createIfcText(v)
+                    elif k == "Name":
+                        v = file.createIfcLabel(v)
+                    else:
+                        v = file.createIfcIdentifier(v)
+                ifcopenshell.api.pset.edit_pset(file, crs, properties=projected_crs)
+        if coordinate_operation:
+            if conversion := ifcopenshell.util.element.get_pset(project, "ePSet_MapConversion"):
+                conversion = file.by_id(conversion["id"])
+                for k, v in coordinate_operation.items():
+                    if k in ("XAxisAbscissa", "XAxisOrdinate", "Scale"):
+                        v = file.createIfcReal(v)
+                    else:
+                        v = file.createIfcLengthMeasure(v)
+                ifcopenshell.api.pset.edit_pset(file, conversion, properties=coordinate_operation)
         return
-    conversion = file.by_type("IfcCoordinateOperation")[0]
-    crs = file.by_type("IfcProjectedCRS")[0]
-    for name, value in coordinate_operation.items():
-        setattr(conversion, name, value)
-    for name, value in projected_crs.items():
-        setattr(crs, name, value)
+    if projected_crs:
+        crs = file.by_type("IfcProjectedCRS")[0]
+        for name, value in projected_crs.items():
+            setattr(crs, name, value)
+    if coordinate_operation:
+        conversion = file.by_type("IfcCoordinateOperation")[0]
+        for name, value in coordinate_operation.items():
+            setattr(conversion, name, value)

src/ifcopenshell-python/ifcopenshell/api/georeference/edit_true_north.py

@@ -50,26 +50,26 @@ def edit_true_north(file: ifcopenshell.file, true_north: Optional[Union[tuple[fl
         # This unsets true north
         ifcopenshell.api.run("georeference.edit_true_north", model, true_north=None)
     """
-    if not true_north:
-        return
-
-    if true_north is None:
-        pass
-    elif isinstance(true_north, (float, int)):
+    if isinstance(true_north, (float, int)):
         x, y = ifcopenshell.util.geolocation.angle2yaxis(true_north)
-    else:
+    elif true_north is not None:
         x, y = true_north
 
     for context in file.by_type("IfcGeometricRepresentationContext", include_subtypes=False):
+        if context.TrueNorth and true_north is None:
+            old_true_north =  context.TrueNorth
+            context.TrueNorth = None
+            if not file.get_total_inverses(old_true_north):
+                ifcopenshell.util.element.remove_deep2(file, old_true_north)
+            continue
+
         if context.TrueNorth:
             if file.get_total_inverses(context.TrueNorth) != 1:
                 context.TrueNorth = file.create_entity("IfcDirection")
         else:
             context.TrueNorth = file.create_entity("IfcDirection")
         direction = context.TrueNorth
-        if true_north is None:
-            context.TrueNorth = None
-        elif context.CoordinateSpaceDimension == 2:
+        if context.CoordinateSpaceDimension == 2:
             direction.DirectionRatios = (x, y)
         else:
             direction.DirectionRatios = (x, y, 0.0)

src/ifcopenshell-python/ifcopenshell/api/georeference/edit_wcs.py

@@ -33,9 +33,19 @@ def edit_wcs(
 ) -> None:
     """Edits the WCS for all geometric contexts to a translation and rotation
 
-    It's recommended to leave the WCS at 0,0,0. You should generally not be
-    setting it to any value. Instead, your project's origin should use a
-    coordinate operation to convert to the projected CRS.
+    Typically, a project's local engineering origin (0, 0, 0) has a coordinate
+    operation (e.g. map conversion) to a projected CRS. If a WCS is provided,
+    the coordinate operation is relative to the WCS, not the local engineering
+    origin.
+
+    For example, if I have an IfcSite with a placement at (10, 0, 0) and a map
+    conversion of (50, 0, 0), my IfcSite's local XYZ is at (10, 0, 0) with an
+    ENH (Easting, Northing, Height) of (60, 0, 0).
+
+    If I then define by WCS at (15, 0, 0), my IfcSite's local XYZ is still at
+    (10, 0, 0) but its ENH is now at (45, 0, 0).
+
+    It's recommended to leave the WCS at 0,0,0. Please :)
 
     :param x: The X translation of the WCS
     :param y: The Y translation of the WCS