Metadata for the four major IBCAO Version 3.0 grids. The structure description is valid for all different formats provided of each grid

File formats:
*grd.gz -- gzip-compressed GMT netCDF grid (note that projection parameters must be provided separately when using the grid in mapping software as no projection information is included in the file)
*Arc.zip -- compressed file containing .asc file(Arc ASCII grid, note that projection parameters, included in .prj file, need to be applied when using the grid in mapping software as no projection information is included in the .asc file)
*sd.zip -- compressed file containing .sd (Fledemaus file for Version 7 or later. Contains projection parameters)
*tif.zip -- compressed GeoTiff with associated Esri World file (.tfw) 

IBCAO_V3_500m_RR
DBM compiled with all multibeam, dense single beam and land data added at 500 x 500 m resolution in a final step using the remove-restore method. This DBM is recommended for analyses requiring the best possible resolution where data exists. Well surveyed areas are clearly distinguished in this grid, specifically if there are nearby areas with sparse data that appear smooth.
Resolution: 500 x 500 m grid cells
Projection: Polar stereographic, true scale 75degN (if scale factor is applied it should be set to 0.982966757777337), latitude of origin 90degN, longitude of origin 0deg.
Horizontal Datum: WGS84
Vertical Datum: Mean Sea Level
Extent (Polar stereographic coordinates): Easting -2904000 to 2904000; 
Northing -2904000 to 2904000
Grid dimension: 11617 x 11617

IBCAO_V3_500m_SM 
DBM compiled with the land data added at 500 x 500 m resolution in a final step using the remove-restore method. This DBM portrays the seafloor with a general and smooth appearance. The smooth representation of the seafloor was achieved by applying a Cosine tapered filter over 6000 m (see gridding methods described in 4.0.). This DBM may be better suited for overview map making than the version described in a) due to its more homogenous and smooth appearance.
Resolution: 500 x 500 m grid cells
Projection: Polar stereographic, true scale 75degN (if scale factor is applied it should be set to 0.982966757777337), latitude of origin 90degN, longitude of origin 0deg.
Horizontal Datum: WGS84
Vertical Datum: Mean Sea Level
Extent (Polar stereographic coordinates): Easting -2904000 to 2904000; 
Northing -2904000 to 2904000
Grid dimension: 11617 x 11617


IBCAO_V3_30arcsec_RR
A re-projected version of IBCAO_V3_500m_RR. 
Resolution: 30 x 30 arc seconds
Projection: Geographic 
Horizontal Datum: WGS84
Vertical Datum: Mean Sea Level
Extent: East-West, -180 to 180; South-North: 64degN to 90degN
Grid dimension:3121 x 43201

IBCAO_V3_30arcsec_SM
A re-projected version of IBCAO_V3_500m_SM. 
Resolution: 30 x 30 arc seconds
Projection: Geographic 
Horizontal Datum: WGS84
Vertical Datum: Mean Sea Level
Extent: East-West, -180 to 180; South-North: 64degN to 90degN
Grid dimension: 3121 x 43201

IBCAO_V3_SID
Source Identification Grid (SID) with the information about the type of source data contributing to a grid cell. Each grid cell in the SID is represented by a numerical value:
0= Land DTMs
1= Multibeam data
2= Single beam 
3= Olex
4= Depth from other Digital Bathymetric Models
5= Depth contours from digitized charts
Resolution: 2000 x 2000 m grid cells
Projection: Polar stereographic, true scale 75degN (if scale factor is applied it should be set to 0.982966757777337), latitude of origin 90degN, longitude of origin 0deg.
Horizontal Datum: WGS84
Vertical Datum: Mean Sea Level
Extent (Polar stereographic coordinates): Easting -2904000 to 290400; 
Northing -2904000 to 2904000
Grid dimension: 2905 x 2905