1 An Analysis of the Survey Decay Term

1 An Analysis of the Survey Decay Term in NOAA's Hydrographic Health Model Using Historic Bathymetric Datasets Nicholas Morgan PENNSYLVANIA STATE UNIVERSITY MGIS PROGRAM ADVISOR: KAREN SCHUCKMAN

What is the Hydrographic Health Model? • Risk based gap analysis • Geospatial Data Driven • Likelihood Parameters (risk) • Consequence Parameters (risk) • Desired Survey Score (gap) • Present Survey Score (gap) • Initial Survey Score (CATZOC) • Decay Function • Change Agents Fandel et al. , 2017 2

The Depreciation Coefficient (The Decay Term) • Exponential Decay Function • Inputs are raster files that provide spatially varying change agents • Output is Present Survey Score as a function of time • The base function’s curve: • CATZOC A -> B in 10 years • CATZOC A -> C in 55 years • Single change agent set to max (5), other two set to min (1) • Requires Decay factor of 0. 022/4 3 Fandel et al. , 2017

4 Question: • How Does the Decay Term Compare to Real Life? • Further the work of Fandel et al. US Hydro 2017 Proposed Solution: • Attempt to assess real data by comparing historic Hydrographic Smooth Sheet data with modern Bathymetric Attributed Grids

Methodology: • 5 Identify suitable subject area Must be an area with large set of historic surveys over past 100 years • Sandy/loose sediment bottom type (consistent with seafloor type in mind when developing HHM) • Perform differencing of historic soundings with modern BAGs (Arc. GIS) • Generate basic statistics to describe results as a function of time (is the amount of change related to time? ) • Attempt to identify when transitions occur from CATZOC A to B and CATZOC B to C (real world “anchor points”) •

Data: NECI Bathymetric Data Viewer 6

Data: • 7 Modern BAGs (24 surveys from 2003 -2012) 1 m and 4 m resolution. Did not attempt to use BAGs with 50 cm resolution • Some BAGs had coordinate system issues after 2012 and were not used • NAD 83, MLLW • • Historic HSSs (24 surveys from 1922 -2001) ASCII XYZ file format • NAD 83, MLLW •

Data: Historic HSSs • ~1 M soundings at various densities 8

Data: Modern BAGs • Full Coverage and Set Line Spacing 9

Process: Part 1 Depth Differencing 10

Process: Part 2 CATZOC Accuracy Thresholds Calculation 11

Final Data Product: ~160, 000 sounding comparisons • 49 Different DETLA_T values • 12

Results: 13

Results: 14

Results: • For DELTA_T with >500 comparisons 15

Considerations: • Not factoring in propagated uncertainty • Data bias to frequently surveyed areas • • Also tend to be more dynamic seafloors Difficulty accounting for Human Debris • One, two , and three sigma do not capture extreme outliers 16

Conclusions: • Unable to definitively define “anchor points” • Need a more focused approach with homogenous environment • • Balance between sample size and subject area size Further work to compare model results for same subject area 17

Acknowledgements • Karen Schuckman, Advisor Penn State MGIS Program • NOAA’s Office of Coast Survey for Historical Information • Corey Allen, Mike Gonsalves, Christy Fandel Office of Coast Survey, Hydrographic Surveys Division 18

References 19 ESRI 2018. Arc. GIS Desktop: Release 10. 6. 1. Redlands, CA: Environmental Systems Research Institute. Fandel, C. , Gonsalves, M. , Keown, P. , Allen, C. , Hick, L. , and Gallagher, B. (2017). Hydrographic Health: A National Overview [Power. Point slides]. Retrieved via email through personal communication. International Hydrographic Organization. (2014). IHO Transfer Standard for Digital Hydrographic Data (IHO Publication S-57, Edition 3. 1, Supplement No. 3). Retrieved from https: //www. iho. int/iho_pubs/standard/S-57 Ed 3. 1/S-57_e 3. 1_Supp 3_Jun 14_EN. pdf National Oceanic and Atmospheric Administration, National Centers for Environmental Information (2019). Bathymetric Data Viewer. Retrieved from https: //maps. ngdc. noaa. gov/viewers/bathymetry/ National Oceanic and Atmospheric Administration, Office of Coast Survey (2012). NOAA Hydrographic Survey Priorities. 2012 Edition. Retrieved from https: //nauticalcharts. noaa. gov/publications/docs/national-hydrographic-survey-priorities/nhsp-full%20 document-2012. pdf National Oceanic and Atmospheric Administration, Office of Coast Survey (2017). History of Coast Survey. Retrieved July 12, 2018 from https: //nauticalcharts. noaa. gov/about/history-of-coast-survey. html National Oceanic and Atmospheric Administration, Office of General Council (2017). United States is an Ocean Nation. Retrieved March 12, 2019 from https: //www. gc. noaa. gov/documents/2011/012711_gcil_maritime_eez_map. pdf United Nations, Oceans and Laws of the Sea (1982). Laws of the Sea, Part V, Article 57. Retrieved March 12, 2019 from http: //www. un. org/depts/los/convention_agreements/texts/unclos_e. pdf