1. New England Height Issues NGS Height-Mod Forum Nashua, NH December 10, 2009 Dan Martin National Geodetic Survey Vermont State Advisor

2. What do we have in common? All NE states are “wet” and all but one state has a salty coastline Much of our topography is similar Shared riverine network Life is good

3. How can Height-Mod help? Disaster preparation/mitigation – Evacuation Routes for coastal storms – Coastal storm inundation models – Stream flow models to predict riverine flooding – Flood plain mapping – Point and non-point pollution/runoff models

4. Hancock, VT

5. Alstead, NH

6. Flood plain mapping

7. Construction – Dams, levees, riverine management – Roads and bridges – Building and other developments

8. Coastal conservation – Accurate ties between geodetic and tidal datums – Planning ecosystem restoration projects – Shoreline restoration projects

9. Narragansett Bay National Estuarine Research Reserve

10. Nautical charting and efficient shipping – Support NOAA’s “Physical Oceanographic Real- Time System” (PORTS) – Supports VDATUM

11. PORTS

12. NGSIDB BM Status (1 st, 2 nd order) CTMAMENHRIVT In NGSIDB259911255401109213802158 Poor3124118201917 Not Found2811501048218196363 Not Rec since Monumented 5332541659216160461 Last Rec ≤ 199015705844475689857374 Last Rec ≤ 19801604993434531277331

13. NE Vertical Control

14. Height-Mod means More Marks

15. More Marks

17. More Marks (OPUS_DB on BM’s)

19. Using Real-Time 95%(RMSEr) (m) 95%(RMSEz) (m) RT1 0.0329670.018825 RT2 0.0332510.0237233 RT3 0.0366220.027924 RT4 0.0361430.026851