Specialty Group Sponsors:Coastal and Marine Geography

Geographic Information Science and Systems

Marine/Coastal GIS and

Acoustic Remote Sensing

AAG Annual Meeting, Denver

April 8, 2005

Photo by

D.J. Wright, E. Lundblad*, E. Larkin^, R. Rinehart, Dept. of Geosciences, Oregon State University

J. MurphyNOAA Coastal Services Center

Benthic Terrain Modeling Algorithms

and Web Distribution

AAG Annual Meeting, Denver

April 8, 2005Photo by

National Marine Sanctuaries

Map courtesy of NOAA National Marine Sanctuary System

Maps courtesy of National Park of American Samoa

Artwork by Jayne Doucette, Woods Hole Oceanographic Institution

By former OrSt grad student Emily Larkin

FBNMS: Some Major Issues• Natural & human impacts

– Crown-of-thorns invasion, hurricanes, bleaching– Illegal fishing, sewage outfall

Photos courtesy of NOAA National Marine Sanctuary System

FBNMS cont. & Research ??s• Prior to 2001…

– Sanctuary largely unexplored below depths of ~30-60 m

– no comprehensive documentation of the plants, animals, and submarine topography.

• Little is known of tropical “twilight zone” – shelf-edge (50-120 m deep) of coral reef habitats

throughout the world

• Best combo of terrain analysis techniques?• Extension of satellite-based scheme

– What is viable classification acoustically?

OrSt & USFMultibeam Surveys to date

By OrSt grad student Emily Lundblad

Shallow Multibeam(May 2001, November 2002)

• Kongsberg-Simrad EM-3000• Fans out 121 beams at 130 deg.• Swaths 3-4 times water depth• Depths in 3-150 m range at survey

speeds of 3-12 knots• cm-resolution w/ dGPS

By OrSt grad student Emily Larkin

Fagatele Bay National Marine Sanctuary, 2001 bathy

Bathymetric Position Index(from TPI, Jones et al., 2000; Weiss, 2001; Iampietro & Kvitekk, 2002)

Measure of where a point is in the overall land- or “seascape”Compares elevation of cell to mean elevation of neighborhood

(after Weiss 2001)

Algorithm compares each cell’s elevation to the mean elevation of the surrounding cells in an annulus or ring.

bpi<scalefactor> = int((bathy - focalmean(bathy, annulus, irad, orad)) + .5)

Bathymetric Position Index

-3m-

|---2---| |---------4-------|

resolution = 3 m

irad = 2 cells (6 m)

orad = 4 cells (12 m)

scalefactor = resolution * orad = 36 m

• Negative bpi = depression

• Positive bpi = crest

• Zero bpi = constant slope or flat

BPI Zone and

Structure

Classification

Flowchart

Emily Lundblad, OrSt M.S. Thesis

Emily Lundblad, OrSt M.S. Thesis

Fish Abundance & BPI

Courtesy of Pat Iampietro, CSU-MB, ESRI UC 2003

Benthic Habitat Pilot Areas, DMWR

2005 HURL Sub & ROV surveys

Ka‘imikai-o-Kanaloa Pisces IV or V

RCV-150

Rugosity• Measure of how rough or bumpy a surface is, how convoluted and complex• Ratio of surface area to planar area

Graphics courtesy of Jeff Jenness, Jenness Enterprises, and Pat Iampietro, CSU-MB

Surface area based onelevations of 8 neighbors

3D view of grid on the left Center pts of 9 cells connectedTo make 8 triangles

Portions of 8 triangles overlapping center cellused for surface area

Emily Lundblad, OrSt M.S. Thesis

Link toSamoanversion of site

Zoom tostudy area

Links to help, data download and info pages

Active tool display

OverviewMap

American Samoa Benthic Terrain American Samoa Benthic Terrain ViewerViewerscallywag.science.oregonstate.edu/website/AmSamoa/viewer.htm… or via dusk.geo.orst.edu/djl/samoa

http://dusk.geo.orst.edu/djl/samoa

Samoan Collaborations & Products

• OSU, NOAA & AS GIS User Group

– Benthic classifications for benthic habitat/MPAs– American Samoa Benthic Terrain Viewer– AS Marine/Coastal Bibliographic Tool– On-island workshops in September 2004– Benthic Terrain Modeler (ArcGIS 8.x/9.x tool)– 3D Visualizations and movies in Fledermaus

• Other work– NOAA Coral Reef Ecosystem Division Mapping – Duke U. Coral reef ecosystem studies

For more information …dusk.geo.orst.edu/djl/samoa

Image courtesy of FBNMS

Structure Classification Decision Tree

Emily Lundblad, OrSt M.S. Thesis