Geolocation Tools
See Also
Geolocating EASE-Grid Data in ENVI
This document describes how to geolocate North, South, and Global EASE-Grid data products using ENVI software.
Importing NSIDC Passive Microwave EASE-Grid Data into ArcInfo
This document describes how to import Passive Microwave EASE-Grid data into ArcGIS.
The tables on this page provide links to software and tools for geolocating and displaying EASE-Grid data sets available at NSIDC.
The software and tools are grouped into the following categories:
- NSIDC DataViewer - Interactive tool for viewing and displaying satellite images for a variety of passive microwave data
- Geolocation Software - Including C, FORTRAN, and IDL (Interactive Data Language) conversion software
- Geolocation Data Files - Look-up files that contain arrays with the latitude and longitude
at the center of each grid cell
Please note that 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.
NSIDC DataViewer
| Tool Name | dataviewer.tar.gz |
|---|---|
| Applicable Data Sets |
Polar Stereographic Projection
Near-Real-Time DMSP SSM/I-SSMIS Daily Polar Gridded Brightness TemperaturesDMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures Near-Real-Time DMSP SSM/I-SSMIS Daily Polar Gridded Sea Ice Concentrations Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data AMSR-E/Aqua Daily L3 25 km Brightness Temperature & Sea Ice Concentration Polar Grids EASE-Grid Projection
Near-Real-Time SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness TemperaturesDMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures Nimbus-7 SMMR Pathfinder Daily EASE-Grid Brightness Temperatures AMSR-E/Aqua Daily EASE-Grid Brightness Temperatures Northern Hemisphere EASE-Grid 2.0 Weekly Snow Cover and Sea Ice Extent Version 4 Quarter-Degree Projection
AMSR-E/Aqua Daily Global Quarter-Degree Gridded Brightness Temperatures |
| Description | The NSIDC DataViewer is an interactive tool for viewing and displaying satellite images from select NSIDC passive microwave data sets. Images in PNG, JPEG, TIFF, and other commonly used image data formats can also be viewed and displayed in a user-defined grid. Up to 64 images can be displayed simultaneously in the DataViewer resizeable graphics window, allowing data users to page through a series of images. Images can be scaled and manipulated either individually or as a group. By moving the cursor over an image, a data user can obtain the latitude and longitude coordinates as well as the image value at the cursor location. After an image or series of images is manipulated, the contents of the graphics window(s) can be saved in a variety of image formats, including PostScript, PNG, JPEG, and TIFF. The DataViewer is a program written in Interactive Data Language (IDL). It can be run in IDL with an IDL license, via the freely distributed IDL Virtual Machine, or as a run-time application. Please Note:
|
| Access | FTP |
Geolocation Software [top]
| Tool Name | ezlhconv.c (With header file, ezlhconv.h, for data set users with knowledge of C programming) |
|---|---|
| Tool Type | C |
| 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 |
| Description | Subroutines in these files can be called from the user's main program, to convert between latitude/longitude and row/column coordinates. |
| Access | FTP |
| Tool Name | ezlhconv.f (For data set users with knowledge of FORTRAN programming) |
| Tool Type | FORTRAN |
| 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 |
| Description | Subroutines in these files can be called from the user's main program, to convert between latitude/longitude and row/column coordinates. |
| Access | FTP |
Geolocation Data Files [top]
For data set users who only have need of the latitude and longitude of the center of any cell in the grid, geolocation data 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.
File Naming Convention
Geolocation data files are named according to the following convention, and as described in the following table:
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-endian 1) |
| 1 As of January 2012, EASE-Grid geolocation files are no longer provided in MSB byte order. |
|
Example geolocation data file name: MLLATLSB
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.
| Tool Names | MLLATooo and MLLONooo |
| Tool Type | Geolocation Data Files |
| 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 |
| 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 |
| Tool Names | MHLATooo and MHLONooo |
| Tool Type | Geolocation Data Files |
| Applicable Data Sets | DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures |
| 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 |
| Tool Names | NLLATooo and NLLONooo |
| Tool Type | Geolocation Data Files |
| 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 |
| 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 |
| Tool Names | NHLATooo and NHLONooo |
| Tool Type | Geolocation Data Files |
| Applicable Data Sets | DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures |
| 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 |
| Tool Names | SLLATooo and SLLONooo |
| Tool Type | Geolocation Data Files |
| 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 |
| 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 |
| Tool Names | SHLATooo and SHLONooo |
| Tool Type | Geolocation Data Files |
| Applicable Data Sets | DMSP SSM/I-SSMIS Pathfinder Daily EASE-Grid Brightness Temperatures |
| 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 |
| Tool Names | NAARILATooo and NAARILONooo |
| Tool Type | Geolocation Data Files |
| Applicable Data Sets | AARI 10-Day Arctic Ocean EASE-Grid Sea Ice Observations |
| 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 |
| Tool Names | Na25LATooo and Na25LONooo |
| Tool Type | Geolocation Data Files |
| 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 AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites |
| 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 | Na252 |
| 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. For a complete grid description, please refer to the Summary of NOAA/NASA Polar Pathfinder Grid Relationships Web page. |
| Access | FTP |
| Tool Names | Sa25LATooo and Sa25LONooo |
| Tool Type | Geolocation Data Files |
| 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 AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites |
| 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 | Sa252 |
| 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. For a complete grid description, please refer to the Summary of NOAA/NASA Polar Pathfinder Grid Relationships Web page. |
| Access | FTP |
2 For information on how the Polar Pathfinder grids are related to one another, see the NOAA/NASA Polar Pathfinder Data Web page.
