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ICESat/GLAS Data at NSIDCHome | Data Summaries | Order Data | Data Releases | Images | Tools | News | FAQs | Research |
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The GLAS science team developed a global mask to flag surface types for use in creating standard ICESat/GLAS data products. This mask was originally for science team use only, to ensure proper transition from one surface type to another, with surface types overlapping. NSIDC is now offering this surface-type mask as a standalone product to the public. It should be used strictly as a tool to learn how surface types were flagged for use in creating standard ICESat/GLAS data products. Other publicly available surface-type masks may be more suitable for other applications, depending on the scientific objective. The surface-type mask is available via FTP.
Following is a reduced-resolution image created from the surface-type values.
Valid pixel values range from 1 to 15. The surface types are bit-coded, and any combination of surface type is allowed. The bit coding is:
1 = land
2 = sea ice (winter maximum extent)
3 = ocean
4 = ice sheet
| Color in above image | Binary value | Decimal value | Surface types | Percentage of the mask |
|---|---|---|---|---|
| Not shown | 00000000 | 0 | No type assigned | 0 |
| 00000001 | 1 | Land | 18.88 | |
| Not shown | 00000010 | 2 | Sea ice | 0 |
| Not shown | 00000011 | 3 | Sea ice + land | 0.02 |
| 00000100 | 4 | Ocean | 43.12 | |
| 00000101 | 5 | Ocean + land | 5.12 | |
| 00000110 | 6 | Ocean + sea ice | 17.06 | |
| 00000111 | 7 | Ocean + sea ice + land | 3.69 | |
| Not shown | 00001000 | 8 | Ice sheet | 0 |
| 00001001 | 9 | Ice sheet + land | 9.18 | |
| Not shown | 00001010 | 10 | Ice sheet + sea ice | 0 |
| Not shown | 00001011 | 11 | Ice sheet + sea ice + land | 0.01 |
| Not shown | 00001100 | 12 | Ice sheet + ocean | 0 |
| Not shown | 00001101 | 13 | Ice sheet + ocean + land | 0.02 |
| Not shown | 00001110 | 14 | Ice sheet + ocean + sea ice | 0 |
| 00001111 | 15 | Ice sheet + ocean + sea ice + land | 2.90 |
