Bathymetric Compilations of theBathymetric Compilations of the Scotia ArcPeter Fretwell

Geographic Information Officer,British Antarctic Survey

ptf@bas.ac.uk

The gridsThe grids

• Science driven

• Medium resolution; 100m‐250mMedium resolution; 100m 250m

• Ascii and arc grid format

• Provided in a range of projections

• Aim is to publish each grid on the webAim is to publish each grid on the web 

The Scotia Sea area

South Georgia Bathymetric Dataset (SGBD)

South Shetland Islands

South Sandwich Islands

DevelopmentDevelopment

• SGBD provided a working methodology

• Source dataSource data– BAS swath

E d h– Endurance swath

– Single beam fisheries data

– Old BAS single beam data

– SoundingsSoundings 

– Gebco

MethodologyMethodology• Source data cleaned• Structured hierarchy developed and source data clipped to thisdata clipped to this

• Gridded in ARCGIS using the TOPOGRID algorithmalgorithm 

• Spikes assessed using– maximum slope – Visual 3D interpretationp

• Cleaned iteratively

SGBD areaSGBD area

SGBD coverageSGBD coverage

SGBD result150m resolution grid published  in 2008

Follow on productsFollow on products• 3 Scientific publications3 Scientific publications,

South Shetland Island Grid• Compiled from a mix of freely available swathy

• Includes new data from HMS SHMS Scott

• No single beam• No single beam

• Coverage good in g gBransfield Straight but poor on the northern h lfshelf

South Sandwich Island Grid

Other possible areas?Other possible areas?

• Scotia Sea map

• South Orkney Island Marine Protected Area?South Orkney Island Marine Protected Area?

• Antarctic Peninsula?