Bedmap2 data now available

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Bedmap2 data now available

Pritchard, Hamish D.
We are pleased to announce that the bedmap2 datasets are now available for download here:
www.antarctica.ac.uk/bedmap2

The bedmap2 paper has just been published in The Cryosphere and is available here:
http://www.the-cryosphere.net/7/375/2013/tc-7-375-2013.pdf
Please cite this paper when referring to bedmap2.

Please note that these datasets make up the final release and supersede the draft versions that we made available for review when we submitted the paper.
All versions with 'draft' in their filename should no longer be used as they contain artefacts.

Below is some more information about the datasets, also available in the bedmap2_readme.txt file that comes with the data:


Bedmap2 datasets and associated grids (5th March 2013)
''''''''''''''''''''''''''''''''''''''''''''''''''''''

You have a choice of four data formats: tiff, ESRI geodatabase (gdb), ASCII (txt) or binary (bin).
(Note that the ESRI geodatabase format is compatible with ArcGIS 10).

For each format, there is a zip file containing ten datasets:

1. bedmap2_bed                          is bed height
2. bedmap2_surface                      is surface height
3. bedmap2_thickness                    is ice thickness
4. bedmap2_icemask_grounded_and_shelves is a mask file showing the grounding line and the extent of the floating ice shelves
5. bedmap2_rockmask                     is a mask file showing rock outcrops
6. bedmap2_lakemask_vostok              is a mask file showing the extent of the lake cavity of Lake Vostok
7. bedmap2_bed_uncertainty              is the bed uncertainty grid shown in figure 12 of the manuscript
8. bedmap2_thickness_uncertainty_5km    is the thickness uncertainty grid shown in figure 11 of the manuscript
9. bedmap2_data_coverage                is a binary grid showing the distribution of ice thickness data used in the grid of ice thickness
10. g104c_geoid_to_wgs84                gives the height conversion values (as floating point) used to convert from WGS84 datum heights to g104c geoidal heights (to convert back to WGS84, subtract this grid)


Grid projection and extents
'''''''''''''''''''''''''''
Each dataset is projected in Antarctic Polar Stereographic projection, latitude of true scale -71 degrees south, datum WGS84.
All heights are in metres relative to sea level as defined by the g104c geoid.

The grid dimensions are 6667 x 6667 cells and the extent is:
Top: 3333500
Left: -3333500
Right: 3333500
Bottom: -3333500

The bedmap2 grid spacing is 1000 m.

Exceptions are the 5 km thickness uncertainty grid (1361 x 1361, top: 3402500, left: -3401500, right: 3403500, , bottom: -3402500),
and the Lake Vostok grid (281 x 112, top: -290500, left: 1189500, right: 1470500, bottom: -402500).

Uncertainty values are in metres.


Data formats
''''''''''''
The tiff, ASCII and gdb data format is 16 bit signed integer for the data grids, the masks are 1 bit or 8 bit integer.
The binary format is little-endian 32-bit single-precision floating point.

To read the binary format into Matlab, use e.g.:

fid=fopen('bedmap2_bed.flt','r','l');
bed=fread(fid,[6667,6667],'float32');
fclose(fid);




Hamish Pritchard
British Antarctic Survey,
Cambridge, UK
+44 1223 221293


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