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EASE-Grid Data Tools
NSIDC provides software and tools for geolocating and displaying EASE Grid data sets at NSIDC. This page provides links to software and tools for geolocating and displaying EASE Grid projection data sets available at NSIDC. All tools are available by FTP.
The software and tools are grouped into the following categories:
- Geolocation Software - Including C, FORTRAN, and IDL (Interactive Data Language) conversion software
(Note: C and FORTRAN only work with EASE-Grid data sets) - Geolocation Data Files - Look-up files that contain arrays with the latitude and longitude at the center of each grid cell
The look-up files for EASE Grid data sets contain arrays with the latitude and longitude at the center of each grid cell. Users who need software to perform the conversion for any location, not just the center of each cell, can choose from the tools listed below or can obtain the Map Transformations Library (Mapx) software.
Geolocation Software
| Tool Name | ezlhconv.c (With header file, ezlhconv.h, for data set users with knowledge of C programming) |
|---|---|
| Tool Type | C |
| Description | Subroutines in these files can be called from the user's main program, to convert between latitude/longitude and row/column coordinates; only works with EASE-Grid data sets |
| Access | FTP |
| Applicable Data Sets | AMSR-E/Aqua Daily EASE-Grid Brightness Temperatures AMSR-E/Aqua Daily L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua 5-Day L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua Monthly L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua Daily L3 Surface Soil Moisture, Interpretive Parms, & QC EASE-Grids Nimbus-7 SMMR Pathfinder Daily EASE-Grid Brightness Temperatures DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures Global Monthly EASE-Grid Snow Water Equivalent Climatology Near-Real-Time SSM/I EASE-Grid Daily Global Ice Concentration and Snow Extent |
| Tool Name | ezlhconv.f (For data set users with knowledge of FORTRAN programming) |
|---|---|
| Tool Type | FORTRAN |
| Description | Subroutines in these files can be called from the user's main program, to convert between latitude/longitude and row/column coordinates; only works with EASE-Grid data sets |
| Access | FTP |
| Applicable Data Sets | AMSR-E/Aqua Daily EASE-Grid Brightness Temperatures AMSR-E/Aqua Daily L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua 5-Day L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua Monthly L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua Daily L3 Surface Soil Moisture, Interpretive Parms, & QC EASE-Grids Nimbus-7 SMMR Pathfinder Daily EASE-Grid Brightness Temperatures DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures Global Monthly EASE-Grid Snow Water Equivalent Climatology Near-Real-Time SSM/I EASE-Grid Daily Global Ice Concentration and Snow Extent Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent Version 3 |
Geolocation Data Files
For data set users who only have the need of the latitude and longitude of the center of any cell in the grid, the following geolocation data file is available.
This section explains the file naming convention used for the following geolocation data files.
These geolocation files contain flat, binary arrays of 4-byte integers containing the latitude or longitude of the respective grid cell in hundred-thousandth degrees. The user should divide the stored integer value by 100,000. to yield decimal degrees, with 1 meter precision. The user is expected to know which byte-ordering convention is required by their system. Files are provided in PC (little-endian/LSB) byte orders.
Depending on the coverage area, which varies for different grids (such as ML, NH, SL, Sa25 and so on), scaled latitudes range from -90.00000 to 90.00000, and scaled longitudes range from -180.00000 to 180.00000 with missing data (such as corners of grids with hemispheric coverage) indicated by scaled value 14316.55765.
Example file name: MLLATLSB
ggpppooo
Where:
| Variable | Description |
|---|---|
| gg | Grid name (NL, NH, SL, SH, ML, MH, NAARI, Na25, Sa25) |
| ppp | Parameter (LAT, LON) |
| ooo | Byte order: LSB: Least Significant Byte/litte-endian MSB: Most Significant Byte/big-endian1 |
| 1As of January 2012, EASE-Grid geolocation files are no longer provided in MSB byte order. | |
| Tool Names | MLLATooo and MLLONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | ML |
| Coverage | Global |
| Resolution | 25 km |
| Dimensions | 1383 x 586 pixels |
| Access | FTP |
| Applicable Data Sets | AMSR-E/Aqua Daily L3 Surface Soil Moisture, Interpretive Parms, & QC EASE-Grids AMSR-E/Aqua Daily EASE-Grid Brightness Temperatures DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures Nimbus-7 SMMR Pathfinder Daily EASE-Grid Brightness Temperatures |
| Tool Names | MHLATooo and MHLONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | MH |
| Coverage | Global |
| Resolution | 12.5 km |
| Dimensions | 2766 x 1171 pixels |
| Access | FTP |
| Applicable Data Sets | DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures |
| Tool Names | NLLATooo and NLLONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | NL |
| Coverage | Northern Hemisphere |
| Resolution | 25 km |
| Dimensions | 721 x 721 pixels |
| Access | FTP |
| Applicable Data Sets | DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures Nimbus-7 SMMR Pathfinder Daily EASE-Grid Brightness Temperatures AMSR-E/Aqua Daily L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua 5-Day L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua Monthly L3 Global Snow Water Equivalent EASE-Grids Global Monthly EASE-Grid Snow Water Equivalent Climatology Near-Real-Time SSM/I EASE-Grid Daily Global Ice Concentration and Snow Extent Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent Version 3 |
| Tool Names | NHLATooo and NHLONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | NH |
| Coverage | Northern Hemisphere |
| Resolution | 12.5 km |
| Dimensions | 1441 x 1441 pixels |
| Access | FTP |
| Applicable Data Sets | DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures |
| Tool Names | SLLATooo and SLLONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | SL |
| Coverage | Southern Hemisphere |
| Resolution | 25 km |
| Dimensions | 721 x 721 pixels |
| Access | FTP |
| Applicable Data Sets | AMSR-E/Aqua Daily EASE-Grid Brightness Temperatures DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures Nimbus-7 SMMR Pathfinder Daily EASE-Grid Brightness Temperatures Global Monthly EASE-Grid Snow Water Equivalent Climatology AMSR-E/Aqua Daily L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua 5-Day L3 Global Snow Water Equivalent EASE-Grids AMSR-E/Aqua Monthly L3 Global Snow Water Equivalent EASE-Grids Near-Real-Time SSM/I EASE-Grid Daily Global Ice Concentration and Snow Extent |
| Tool Names | SHLATooo and SHLONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | SH |
| Coverage | Southern Hemisphere |
| Resolution | 12.5 km |
| Dimensions | 1441 x 1441 pixels |
| Access | FTP |
| Applicable Data Sets | DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures |
| Tool Names | NAARILATooo and NAARILONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | NAARI |
| Coverage | Subset of the Northern Hemisphere |
| Resolution | 25 km |
| Dimensions | 721 x 721 pixels |
| Access | FTP |
| Applicable Data Sets | AARI 10-Day Arctic Ocean EASE-Grid Sea Ice Observations |
| Tool Names | Na25LATooo and Na25LONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | Na25 |
| Coverage | Subset of the Northern Hemisphere |
| Resolution | 25 km |
| Dimensions | The Na25 EASE-Grid is a subset of the 25 km Northern Hemisphere Azimuthal EASE-Grid, including the center 361 columns by 361 rows, with the North Pole at the center of the center-most grid cell. |
| Access | FTP |
| Applicable Data Sets | Polar Pathfinder Daily 25 km EASE-Grid Sea Ice Motion Vectors National Ice Center Arctic Sea Ice Charts and Climatologies in Gridded Format |
| Tool Names | Sa25LATooo and Sa25LONooo |
|---|---|
| Tool Type | Geolocation Data Files |
| Description | Provides latitude and longitude for the center of any cell in the grid. For additional details, please refer to the Geolocation Data Files section of this Web page. |
| Grid Name | Sa25 |
| Coverage | Subset of the Southern Hemisphere |
| Resolution | 25 km |
| Dimensions | The Sa25 EASE-Grid is a subset of the 25 km Northern Hemisphere Azimuthal EASE-Grid, including the center 321 columns by 321 rows, with the North Pole at the center of the center-most grid cell. |
| Access | FTP |
| Applicable Data Sets | Polar Pathfinder Daily 25 km EASE-Grid Sea Ice Motion Vectors National Ice Center Arctic Sea Ice Charts and Climatologies in Gridded Format |
Related Articles
Geolocating EASE-Grid Data in ENVI
The Geolocating EASE-Grid Data in ENVI document describes how to geolocate North, South, and Global EASE-Grid data from the DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures product using ENVI Software.
