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EASE-Grid 2.0 Land Cover Classifications Derived from Boston University MODIS/Terra Land Cover Data, Version 1
These data provide land cover classifications derived from the Boston University MOD12Q1 V004 MODIS/Terra 1 km Land Cover Product (Friedl et al. 2002). The data are available in various EASE-Grid 2.0 azimuthal and global projections, in multiple spatial resolutions ranging from 3 km to 100 km. The data are in flat binary, 1 byte files that are stored by row.
Geographic Coverage
Spatial Coverage: |
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Spatial Resolution: |
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Temporal Coverage: |
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Temporal Resolution: | Not specified |
Parameter(s): |
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Platform(s) | TERRA |
Sensor(s): | MODIS |
Data Format(s): |
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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 Cover Classifications 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/XR8523MC24TB. [Date Accessed].Detailed Data Description
These data sets use the International Geosphere Biosphere Programme (IGBP) land cover classes from Boston University's (BU) 1 km MOD12Q1 product (Friedl et al. 2002). Table 1 lists the IGBP land cover classes. For each projection/spatial resolution combination, the 1 km MOD12Q1 product is resampled to the coarser resolution grids: 3 km, 5 km, 6.25 km, 9 km, 10 km, 12.5 km, 25 km, 36 km, and 100 km. See the Data Acquisition and Processing section of this document for more information.
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 |
The data are in flat binary, 1 byte files that are stored by row. Each of the resolution and projection combinations are described by a Grid Parameter Definition (GPD). Tables 2 and 3 list the short name for each GPD. For each GPD, there are 17 land cover files, one for each IGBP land cover class (Table 1). For the 17 land cover files, each pixel in the grids is the percent of land covered by the IGBP class noted in the file name. For example, the file EASE2_N25km.igbp_landclass.01.720x720.bin is the 25 km EASE-Grid 2.0 Northern Hemisphere file that contains a 721x721 grid where each grid cell represents the percent of land in that cell that was characterized as IGBP class 1 (Evergreen needleleaf forest). See the Data Acquisition and Processing section of this document for information on how these percents were derived. Pixels that are off the map or were undefined in the input data were given the value 255. Tables 2 and 3 list the resolution, grid dimensions, and files size for each GPD. See Table 4 for the file naming convention.
Projection | Resolution | 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 | Resolution | 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 | 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/nsidc0608_classification_ease/. This directory contains a subdirectory for each EASE-Grid projection—north, south, and global—with subfolders labeled by resolution (12km, 25km). Each resolution folder contains 17 land classification files corresponding to the parent projection and resolution.
EASE-Grid 2.0
Data are available via FTP in ftp://sidads.colorado.edu/pub/DATASETS/nsidc0610_classification_ease2/. This directory contains a subdirectory for each EASE-Grid 2.0 projection—north, south, global, and temperate—with subfolders labeled by resolution (3km, 3.125km, 5km, 6.25km, etc.). Each subfolder folder contains 17 land classification files corresponding to the parent projection and resolution.
EASE-Grid
Example File Name: Nl.igbp_landclass.01.721x721.bin
Generic File Name: Pr.igbp_landclass.CC.colxrow.bin
EASE-Grid 2.0
Example File Name: EASE2_N25km.igbp_landclass.01.720x720.bin
Generic File Name: EASE2_PRRkm.igbp_landclass.CC.colxrow.bin
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-Grid: r EASE-Grid 2.0: RRkm |
Resolution (EASE-Grid). h = 12.5km, l = 25km Resolution in km (EASE-Grid 2.0). For example: 03km = 3 km; 3.125km = 3.125 km; 05km = 5 km... |
igbp_landclass | Land cover classification file. |
CC | 2-digit land cover classification code. See Table 1 for values. |
colxrow | Grid dimensions in pixels, column x row. |
.bin | Binary file extension. |
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.
Land classifications are derived from MODIS (Version 4) data obtained between July and December, 2000 (Friedl et al. 2002).
These data provide land cover classifications in percent area per grid cell using the IGBP land cover classifications described in Table 1. They were derived from 1 km classifications in MOD12Q1 according to 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

On the left is the set of 1 km2 pixels from the input data that map to the coarser resolution pixels on the right. On the right is one of the coarser pixels from each of the classification files and the percent that the file contains that land classification.
These data are derived from the Boston University MODIS/Terra 1 km Land Cover product (MCD12Q1, V004), which utilizes the Interrupted Goode Homolosine projection. MCD12Q1 data are reprojected to either EASE-Grid or EASE-Grid 2.0 and resampled by counting the number of 1 km observations for each classification that map into the target coarser resolution cell. The counts are then converted to percentages and a separate map is generated for each IGBP land cover classification (see Table 1). As such, the set of land classifications for each grid/resolution comprises 17 files.
Example:- To resample the 1 km MCD12Q1 data to each of the coarser EASE-Grid and EASE-Grid 2.0 resolutions, a certain number of 1 km2 cells are mapped to the given coarser-resolution cells (Figure 1).
- For each of the 17 coarser resolution land class files, each separate IGBP class type is counted in each of the sets of 1 km2 MCD12Q1 data. For example, if a nine-pixel set of 1 km2 cells happens to map to a coarser resolution EASE-Grid cell, as shown in Figure 1, then seven 1 km2 pixels are characterized as Class 1, two pixels are characterized as Class 2, and zero pixels are characterized as the other 15 classes. This means that this pixel in the Class 1 output data file is 7/9 (78%) covered by Class 1, that same pixel in the Class 2 file is 2/9 (22%) covered by Class 2, and that pixel in all of the other files (Class 3 to 17) is zero (Figure 1).
- The counts are then converted to a percent. The floating point percent values were rounded to the nearest integer percent. There were three problems with the result:
- Water and missing value ambiguity: Boston University used zero for water instead of the IGBP value of 17. Because this is a land product, there were large areas in the oceans that were assigned 255 (fill) instead of 0 (water). See #1 in Data Corrections Applied section for the correction used.
- Round-off error: The sum of the integer percent values at any pixel location ranged from 98 to 102, due to round-off error. See #2 in Data Corrections Applied section for the correction used.
- Anomalous water in the Ross Ice Shelf: Due to an unexplained artifact in the original 1 km data, a small number of resampled pixels with an area of about 6000 square kilometers in the middle of the Ross Ice Shelf were coded as partially open water, rather than the expected snow and ice category (IGBP class 15). See #3 in Data Corrections Applied section for the correction used.
- Pixels that are off the map or were undefined in the input data were given the fill value 255.
- Data Corrections Applied
In order to produce a more consistent data set, NSIDC performed the following corrections:- Water class 17 was derived from MOD12Q1 classes 0 through 16 with the following equation: water class = 100 - (sum of nonwater classes, 1-16)/(sum of all classes, 0-16).
- To adjust the round-off error, the integer sum at each pixel was normalized to 100 by examining the original floating point values and reversing what would have rounded up or down for those values with decimal parts closest to 0.5; this was only done for enough classes to achieve a sum of 100. Since non-normalized sums ranged from 98 to 102, this adjusted the rounding in any given category by at most three percentage points.
- The misclassified open water in the Ross Ice Shelf was changed to class 15.
- The pixel containing the North Pole in the Northern Hemisphere was undefined in the original data set. It was set to 100 percent water.
Refer to Data Corrections Applied in the Data Acquisition and Processing section.
The following tables show the version history for these data sets.
Table 5. Version History for EASE-Grid Land Cover Classification | Table 6. Version History for EASE-Grid 2.0 Land Cover Classification | ||||
Version | Date | Description | Version | Date | Description |
---|---|---|---|---|---|
V1.0 | 2004 | The EASE-Grid Land Cover Classification data 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 old file name for the Northern Hemisphere 25 km class 01 file was changed as follows:
The algorithms and processing were not changed. |
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 class 01 file was changed as follows:
The algorithms and processing were not changed. |
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
Document Information
DOCUMENT CREATION DATE
October 2014
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