GLIMS Impacts

The Global Land Ice Measurements from Space (GLIMS) project at NSIDC has implemented a database of information on glaciers from around the world in order to monitor their health. Glacier outlines extracted from satellite images, as well as from other sources, are ingested into the GLIMS Glacier Database in order to document and monitor changes in the spatial extents of glacier systems through time. In June 2007, the database contains data on around 52000 glaciers. Glacier outlines, snow lines, areas of debris cover, glacial lakes, and other information can be viewed on-line in our Web-based interactive map application, connected to other software via OpenGIS Consortium (OGC) protocols, or downloaded in several popular data formats. The application is designed to serve users ranging from secondary students to Earth scientists.

Web-based interactive maps are common these days, but the ability to download only your data of interest in your choice of formats is rare, if not unique. After zooming in to a particular region on the map, or finding a set of glaciers by constraining by name or size or other attributes, the user can download the data on the glaciers that matched the search in a choice of formats, including Google Earth (KML), ESRI Shapefiles, Generic Mapping Tools (GMT), MapInfo, and Geography Markup Language (GML). This gives students, teachers, scientists, and policy makers the ability to visualize or analyze glacier data in their favorite software packages.

Providing data according to OGC protocols allows people to use GLIMS glacier data as if it were in a file on their local computer. For example, a user of a GIS desktop application could combine glacier layers with their own data to see how they relate spatially.

With increasing volume of satellite imagery from NASA and other sources, as well as the trend toward easy-to-use geospatial applications such as Google Earth, GPS receivers, and desktop computer software, the public is increasingly accustomed to using geospatial data in a range of applications. Allowing users of GLIMS data to download data in many open non-proprietary formats means the data will be used by more people, and ultimately have a greater impact on society.

Imagery from the ASTER instrument, archived at the LP-DAAC at EROS/USGS, is the primary source of glacier information for GLIMS. Glacier outlines extracted from ASTER images, as well as from other sources, are ingested into the GLIMS Glacier Database in order to document and monitor changes in the spatial extents of glacier systems through time.

Due to the high volume of ASTER imagery available, it is often difficult for GLIMS Regional Centers (GLIMS data providers, or RCs) to find images suitable for performing glacier analysis. Difficulties include finding ASTER scenes that: cover a specific region of the world, are captured during optimal times of the year, have minimal cloud cover, and have the best sensor gain settings for snowy scenes.

In order to address some of these difficulties, the GLIMS Project, through collaboration with the LP-DAAC at EROS/USGS, has created a collection of more than 150,000 ASTER images tailored specifically for those interested in glaciers. This dataset has been spatially selected from the pool of all available ASTER scenes based on an intersection with GLIMS regions that are known to contain glaciers. With this dataset, we make it easier to find, view, and order ASTER images that have been captured over areas where glaciers may exist.

The GLIMS ASTER Browse data can be viewed in two ways: from within the Web-based GLIMS Glacier Viewer, or within Google Earth. Both viewing options provide image metadata, as well as a browse image that has approximately 150-meter resolution. The tools also allow for the temporal constraint of the data. Both options provide a spatial context in which to view the the browse images, as well as ways to order the full ASTER image scenes from the LP-DAAC.