Get Data
DOWNLOADING DATA VIA HTTPS
To learn more about Earthdata Login and register for an account, please see How to Register with Earthdata Login. Once you have logged in, data can be downloaded via a Web browser, command line, or client. For help with downloading data, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login.
EASE-Grid 2.0 Land-Ocean-Coastline-Ice Masks Derived from Boston University MODIS/Terra Land Cover Data, Version 1
These Land-Ocean-Coastline-Ice (LOCI) files provide land classification masks derived from the Boston University MOD12Q1 V004 MODIS/Terra 1 km Land Cover Product (Friedl et al. 2002). The masks are available in various EASE-Grid 2.0 azimuthal and global projections, at various spatial resolutions ranging from 3 km to 100 km. The masks are in flat binary, 1 byte files stored by row. Quick-look browse images of the masks are also available in PNG (.png) format.
Geographic Coverage
Spatial Coverage: |
|
---|---|
Spatial Resolution: |
|
Temporal Coverage: |
|
Temporal Resolution: | Not specified |
Parameter(s): |
|
Platform(s) | TERRA |
Sensor(s): | MODIS |
Data Format(s): |
|
Version: | V1 |
Data Contributor(s): | Mary Brodzik, Kenneth Knowles |
Metadata XML: | View Metadata Record |
Data Citation
As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.
Brodzik, M. J. and K. Knowles. 2011. EASE-Grid 2.0 Land-Ocean-Coastline-Ice Masks Derived from Boston University MODIS/Terra Land Cover Data, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: http://dx.doi.org/10.5067/VY2JQZL9J8AQ. [Date Accessed].Detailed Data Description
Masks are provided as flat binary, 1 byte files stored by row. Quick-look browse images are also available in PNG (.png) format. The masks indicate the location of land, water, coastline, and ice using coded integers. Refer to Table 1 for the key to these values:
Value | Description |
---|---|
0 | Land |
101 | Ice |
252 | Coastline |
254 | Off the map |
255 | Water |
Note: The software used to generate the LOCI masks sets the width of coastline pixels to a user-specified value. For this data set, the coastline width has been set to zero, i.e. the masks do not contain the value for coastline (252). Masks with non-zero coastline pixel widths are available upon request by contacting NSIDC User Services.
Each resolution and projection combination is described by a Grid Parameter Definition (GPD). The short name, grid dimensions, and file sizes for each GPD are provided in Table 2 for EASE-Grid and in Table 3 for EASE-Grid 2.0. See Table 4 for the file naming convention.
Projection | Available Resolutions | Grid Dimensions (r x c) | File Size | GPD Short Name |
---|---|---|---|---|
N., S. Hemisphere | 25 km | 721 x 721 | 508 KB | Nl, Sl |
12.5 km | 1441 x 1441 | 2 MB | Nh, Sh | |
Global | 25 km | 1383 x 586 | 792 KB | Ml |
12.5 km | 2766 x 1171 | 3.1 MB | Mh |
Projection | Parent Grid | Available Resolutions | Grid Dimensions (r x c) | File Size | GPD Short Name |
---|---|---|---|---|---|
N., S. Hemisphere |
100 km | 100 km | 180 x 180 | 32 KB | EASE2_N100km, EASE2_S100km |
10 km | 1800 x 1800 | 3.1 MB | EASE2_N10km, EASE2_S10km | ||
5 km | 3600 x 3600 | 13 MB | EASE2_N05km, EASE2_S05km | ||
36 km | 36 km | 500 x 500 | 245 KB | EASE2_N36km, EASE2_S36km | |
9 km | 2000 x 2000 | 3.9 MB | EASE2_N09km, EASE2_S09km | ||
3 km | 6000 x 6000 | 35 MB | EASE2_N03km, EASE2_S03km | ||
25 km | 25 km | 720 x 720 | 507 KB | EASE2_N25km, EASE2_S25km | |
12.5 km | 1440 x 1440 | 2 MB | EASE2_N12.5km, EASE2_S12.5km | ||
6.25 km | 2880 x 2880 | 8 MB | EASE2_N6.25km, EASE2_S6.25km | ||
3.125 km | 5760 x 5760 | 33 MB | EASE2_N3.125km, EASE2_S3.125km | ||
Global | 36 km | 36 km | 964 x 406 | 383 KB | EASE2_M36km |
9 km | 3856 x 1624 | 6 MB | EASE2_M09km | ||
3 km | 11568 x 4872 | 54 MB | EASE2_M03km | ||
25 km | 25 km | 1383 x 584 | 792 KB | EASE2_M25km | |
12.5 km | 2776 x 1168 | 3.1 MB | EASE2_M12.5km | ||
6.25 km | 5552 x 2336 | 13 MB | EASE2_M6.25km | ||
Temperate¹ | 25 km | 25 km | 1388 x 540 | 750 KB | EASE2_T25km |
12.5 km | 2776 x 1080 | 3.0 MB | EASE2_T12.5km | ||
6.25 km | 5552 x 2160 | 12 MB | EASE2_T6.25km | ||
3.125 km | 11104 x 4320 | 50 MB | EASE2_T3.125km | ||
¹The temperate grid is a subset of the global grid that omits the most poleward latitudes. It extends from 67 N° to 67 S°. |
EASE-Grid
Data are available via FTP in ftp://sidads.colorado.edu/pub/DATASETS/nsidc0607_loci_ease/. This directory contains a subdirectory for each EASE-Grid region: north, south, and global. The available land masks and browse images for a region are stored within the corresponding subdirectory.
EASE-Grid 2.0
Data are available via FTP in ftp://sidads.colorado.edu/pub/DATASETS/nsidc0609_loci_ease2/. This directory contains a subdirectory for each EASE-Grid region: north, south, and global. The available land masks and browse images for a region are stored within the corresponding subdirectory.
EASE-Grid
Example File Name: Nl.LOCImask_land50_coast0km.721x721bin
Generic File Name: Pr.LOCImask_landTT_coastZkm.colxrow.ext
Refer to Table 4 for the valid values for the file name variables listed above.
EASE-Grid 2.0
Example File Name: EASE2_N25km.LOCImask_land50_coast0km.720x720.bin
Generic File Name: EASE2_PRRkm.LOCImask_landTT_coastZkm.colxrow.ext
The following table describes this data set's file name variables:
Variable | Description |
---|---|
EASE2_ | File contains EASE-Grid 2.0 data. Files without this variable contain EASE-Grid data. |
P | Projection. Values: N = N. Hemisphere; S = S. Hemisphere; M = global; T = temperate |
EASE: r EASE 2.0: RRkm |
Resolution (EASE-Grid). h = 12.5km, l = 25km |
LOCImask | File contains the LOCI mask |
landTT | Identifies the land threshold used in the processing of these files (50: 50% cut off used). |
coastZkm | Identifies the width of the coast used in the processing of these files. Coastlines = 0 px for this data set, i.e. value for coastline not present in data. |
colxrow | Grid dimensions in pixels, column x row. |
.ext |
File extension. .bin = binary data file, .png = PNG browse image. |
EASE-Grid
These data cover the entire globe and are provided in projections for the entire globe and for the Northern and Southern Hemispheres. See Table 2 for a complete listing of the projection/resolution combinations.
EASE-Grid 2.0
These data cover the entire globe and are provided in projections for the entire globe and for the Northern and Southern Hemispheres. See Table 3 for a complete listing of the projection/resolution combinations.
Projection and Grid Description
These data are provided in both the EASE-grid projection and the EASE-Grid 2.0 projection. The grid sizes are given in Table 2 and Table 3, respectively. For complete details on these two projections, see the EASE-Grid Format Description and the EASE-Grid 2.0 Format Description web pages.
The LOCI masks are derived from MODIS (Version 4) data obtained between July and December, 2000 (Friedl et al. 2002).
Software and Tools
See the EASE-Grid | Geolocation Tools page for links to software and tools that geolocate and display EASE-Grid data sets.
Data Acquisition and Processing
The LOCI masks were generated from the following input data:
- EASE-Grid Land Cover Classifications Derived from Boston University MODIS/Terra Land Cover Data, Version 1
- EASE-Grid 2.0 Land Cover Classifications Derived from Boston University MODIS/Terra Land Cover Data, Version 1
These EASE-Grid and EASE-Grid 2.0 land cover data sets were derived from the Boston University MODIS/Terra 1 km Land Cover Product (MCD12Q1, V004). MCD12Q1 utilizes the 17 International Geosphere Biosphere Programme (IGBP) land cover classes in Table 5.
LOCI masks were generated using the follow algorithm:
- For each grid cell, calculate the percent land by summing the percent of IGBP non-water classes (1-16).
- Cells with >= 50% ice are classified as ice.
- Cells with >= 50% land and < 50% ice are classified as land
- Any remaining cells are classified as ocean (including lakes and inland water).
Note: The LOCI masks available as part of this data set have their coastline widths set to zero pixels. As such the files do not include the value for coastline. To obtain masks with custom coastline widths, please contact NSIDC User Services.
Class Number | Category | Class Number | Category |
---|---|---|---|
01 | Evergreen needleleaf forest | 10 | Grasslands |
02 | Evergreen broadleaf forest | 11 | Permanent Wetlands |
03 | Deciduous needleleaf forest | 12 | Croplands |
04 | Deciduous broadleaf forest | 13 | Urban and built-up |
05 | Mixed forests | 14 | Cropland/natural vegetation mosaic |
06 | Closed shrublands | 15 | Snow and ice |
07 | Open shrublands | 16 | Barren or sparsely vegetated |
08 | Woody savannas | 17 | Water bodies |
09 | Savannas |
Errors in the input data represent the primary source of error in this data set. See Data Corrections Applied in the User Guide for EASE-Grid and EASE-Grid 2.0 Land Cover Classifications Derived from Boston University MODIS/Terra Land Cover Data.
The following tables show the version history for these data sets.
Table 6. Version History for EASE-Grid LOCI Masks | Table 7. Version History for EASE-Grid 2.0 LOCI Masks | ||||
Version | Date | Description | Version | Date | Description |
---|---|---|---|---|---|
V1.0 | 2004 | The EASE-Grid LOCI masks were created as an ancillary data set, not part of the official NASA DAAC data catalog. Instead, some of the data were distributed as ancillary data via a web page and others via personal communication with the authors. | V1.0 | 2011 | The EASE-Grid 2.0 LOCI masks were created as an ancillary data set, not part of the official NASA DAAC data catalog. Instead, the data were distributed via personal communication with the authors. |
V1.1 | 2014 |
These data were accessioned into the NASA DAAC catalog and given a data set ID number. During this process, NSIDC changed the title, filenames, and organization of the data to improve usability. For example, the file name for the Northern Hemisphere 25 km LOCI mask was changed as follows:
|
V1.1 | 2014 | These data were accessioned into the NSIDC system and given a data set ID number. During this process, NSIDC changed the title, filenames, and organization of the data to improve usability. For example, the old file name for the Northern Hemisphere 25 km mask was changed as follows:
|
References and Related Publications
Contacts and Acknowledgments
Mary J. Brodzik
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449 USA
Kenneth W. Knowles
Operational Systems, Inc.
6514 Fairways Dr.
Longmont, CO 80503 USA
Access complete Knowledge Base
Questions? Please contact:NSIDC User Services
Phone: 1 303 492-6199
Email: nsidc@nsidc.org