Antarctic Cryosphere Access Portal (A-CAP) Map Server

The Antarctic Cryosphere Access Portal (A-CAP) is a geo-visualization and data download tool developed at the NSIDC Antarctic Glaciological Data Center (AGDC). A-CAP provides access to AGDC data and other Antarctic parameters including glaciology, ice core data, snow accumulation, satellite imagery, Digital Elevation Models (DEMs), sea ice concentration, and many other cryosphere-related measurements.

A-CAP is an interactive map interface that allows users to zoom in and out, overlay coastlines, place names, latitude/longitude, and other geographic information, and access data. A-CAP map images and source data are also accessible via the Open Geospatial Consortium (OGC) Web Map Service (WMS), Web Feature Service (WFS), and Web Coverage Service (WCS). For details and instructions on accessing A-CAP data using these portals, see the A-CAP: OGC Services Web page.


A-CAP is still in active development. Not all features are available in the Beta version. For notification on new features and data, see the A-CAP News Web page or sign up for the A-CAP RSS Feed.

The following features are currently available:

  • Access WMS, WFS, and WCS OGC services
  • Interactively view one or more layers from a variety of overlays, basemaps, and sea ice climatologies. Available base maps include satellite imagery, DEMs, and snow accumulation
  • View a map legend, reference map, and scale bar
  • Zoom in and out and re-center the map
  • Adjust a variety of map parameters, such as the map size, map center, map extent, and background color
  • Save the displayed map as an image file
  • Save the displayed map as a GeoTIFF or KMZ (Google Earth)
  • Download the source data for each of the layers displayed in the map, including options for data format, map projection, resolution, and subsetting to the current map view
  • Obtain citation and background information for each layer, including links to further documentation and data access
  • Click on the map to get the data values for that location

The following features are planned, but not yet available:

  • Dynamically view the location of the cursor while scrolling over the map image
  • Zoom to the spatial area of interest by drawing a rectangle on the map

How To Cite A-CAP

Scambos, Ted, John Maurer, Rob Bauer, Jennifer Bohlander, Terry Haran, and Katherine Leitzell. 2008. A-CAP: The Antarctic Cryosphere Access Portal. Boulder, Colorado USA: National Snow and Ice Data Center. Available at

How To Cite A-CAP Data Sources

Citations for A-CAP data sources are available by clicking on the information icon ( ) next to each layer in the layer-selection frame. Please cite the sources that you have used.


The continued development of this map server application is supported by NASA grants for Antarctic ice velocity mapping (NNG05GO82G) and two awards under the Making Earth System Data Records for Use in Research Environments (MEaSURES) program. Initial development was supported under NSF grant OPP-03338134 to the Antarctic Glaciological Data Center (AGDC).

A-CAP was developed using MapServer, an Open Source development environment for building spatially-enabled Internet applications. Thanks also to the following for their contributions to the A-CAP Web site or for their useful utilities: Scott Lewis (Mapx, APIs), Ross Swick (Mapx), Ken Knowles (Mapx), Bruce Raup (GLIMS), Betsy Sheffield (NSIDC User Services), Ian Howat (G-CAP), Mark Fahnestock (MOA), Cindy Brewer (Color Brewer), Matt Kruse (DHTML tree), Frank Warmerdam (FWTools), GDAL, OGR, PROJ.4, and the MapServer-Users e-list.