1. Uncertainty Representation in Hydrographic Surveys and Products
Brian Calder
Center for Coastal and Ocean Mapping and NOAA/UNH Joint Hydrographic Center

4. “How much do we know about the area?”
We’re answering the question:
“What did we do?”
… and not:
“How much do we know about the area?”
The user’s question is more like:
“What’s my chance of going there safely?”

17. Conclusions
Some uncertainty representation for the user is required to complement the chart
We can flexibly assess uncertainty from physical vessel models and available bathy/non-bathy data
Track-oriented models support variational route planning & real-time decision support
Area-oriented models support display & monitoring
A risk-based uncertainty model can:
provide unified “uncertainty” for all data types
give flexibility in representation & computation
answer user questions directly

18. Tail-End Charlie – Blank side to mark the end of the talk without an “End of Slideshow” slide appearing.

19. Representation Design Goals
Computable anywhere, all data types
Compensate for level of knowledge in data
Flexible: must allow non-bathy constraints
Readily interpretable scalar assessment
Include non-hydrographic costs
(… and portrayable on paper as well as ENC)

20. Updated Object Density
Prior Object
Density
Mean UKC
Distribution

23. Challenges Calibration & Complexity
Assessment of Geological Components
Management of user inputs for validity
Assessment of “worst case” for static display
Institutional acknowledgement of risk
Acceptance of risk transfer to users