Chris Wright Managing Consultant chris.wright@1Spatial

1. Chris Wright Managing Consultant chris.wright@1Spatial.com

2. The current situation • Assets captured against supplied base data • Aligned to the base data • As an offset from the base data • Base data continuously being updated • Often in small discreet areas

3. What needs to happen • Update Asset information to match shifts • Maintain alignment • Maintain offset • Needs to be easy and simple to do

4. Our process • Utilises a piecewise triangular warp (Delaunay) • Create triangular mesh from the shift vector data • Shift vectors may exist • Shift vectors can be created • Transform between triangles • Delivers smaller more accurate transformations • Nearby co-ordinates have a much bigger effect on transform

5. Our process

6. Our process • Why Delaunay ? • A well-established mathematical algorithm • Nearby control points have bigger effect than distant control • Triangles only dependent on set of nearest neighbour control points • Movements to control points beyond set that have no effect

7. An example The original basemap cadastre

8. An example The original basemap cadastre with original annotation

9. An example The original basemap cadastre with original annotation, together with the current cadastre shown in blue

10. An example The original basemap cadastre with original annotation, together with the current cadastre shown in blue and the shift vectors shown inpink

11. An example The original basemap cadastre with original annotation, together with the shift vectors shown inpink and the shifted original basemap shown inorange

12. An example The original basemap cadastre with original annotation, together with the shift vectors shown inpink, the shifted original basemap and shifted original annotation shown inorange

13. An example Finally the current basemap cadastre and the shifted annotation

14. Demonstration

15. Chris Wright Managing Consultant chris.wright@1Spatial.com