When dealing with polygon features in Oracle Spatial, the feature definition provides an option to toggle support for non-planer shapes. This option is available for both polygons and polygon collections and determines the contents of the Plane Constraint drop down list.
For a registered feature class, the value of this toggle would be stored in the feature’s registration information in the ECRelationalDbMapping class property allowNonPlanar. See last paragraph for discussion of this property’s usage during Oracle geometry validation.
When Support non-planar shapes is toggled ON, the drop-down list contents are:
Area of the projected polygon to the ground
- Flattens the non-coplanar polygon geometry to the XY plane/top view when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_Horizontal (parallel to the XY plane)
Area of the projected polygon to the average plane
- Flattens the non-coplanar polygon geometry to an average plane when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_Average (Best average plane from non-coplanar polygon)
Area of the mesh
- Area of the polygon mesh when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_None (No plane calculation)
If Support non-planar shapes is toggled OFF, the drop down list contents are:
Area of the projected polygon to the ground
- Flattens the non-coplanar polygon geometry to the XY plane/top view when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_Horizontal (parallel to the XY plane)
Area of the polygon
- Area of the polygon mesh when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_None (No plane calculation)
For a polygon collection feature definition, if Support non-planar shapes is toggled ON, the drop down list contents are:
Area of the projected polygon collection to the ground
- Flattens the non-coplanar polygon geometry to the XY plane/top view when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_Horizontal (parallel to the XY plane)
Total of the areas of the projected polygon to the average plane per polygon
- Flattens the non-coplanar polygon geometry to an average plane when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_Average (Best average plane from non-coplanar polygon)
Total of the areas of the meshes
- Totals the area of each mesh when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_None (No plane calculation)
If Support non-planar shapes is toggled OFF, the drop down list contents are:
Area of the projected polygon collection to the ground
- Flattens the non-coplanar polygon geometry to the XY plane/top view when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_Horizontal (parallel to the XY plane)
Total area of all polygons
- Totals the area of each mesh when calculating the area.
- XFM API: XFMPOLYGONPLANECALCULATIONCONSTRAINT_None (No plane calculation)
For a registered feature class, the value of this drop-down list would be used to determine the value of the isHorizontal property in the ECRelationalDbMapping class of the feature’s registration information. The allowNonPlanar and isHorizontal property values are used during posting to Oracle when validating geometry.
When allowNonPlanar is True/ON, and isHorizontal is set as:
- False, then geometry validation is not performed.
- True, then geometry validation is performed with Oracle 10g validation mode which is more forgiving with non-coplanar geometry.
When allowNonPlanar is False/OFF, then geometry validation is performed normally, meaning with whatever validation their database supports by default (e.g. 11g, 12c).