http://lima.usgs.gov

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2007–3116

December 2007

Antarctica—a frozen dream comes to life through the extraordinary focus of LIMA, where you can pan and zoom in to view areas of the 

continent never before seen with such clarity. Discover the different blue tones of ice in glaciers, lakes, and ice flows. Clearly discriminate 

between ice and snow. See jagged mountains and the dry (ice-free) valleys. Follow the coast and feel as though you are watching calving 

icebergs. This section of the Natural-Color, Pan-Sharpened LIMA (bands 3, 2, 1) includes McMurdo Station (United States), the largest 

research base in Antarctica, at the tip of Hut Point Peninsula on Ross Island. Also visible are the Erebus Glacier Tongue, the Koettlitz and 

Ferrar Glaciers, and the Royal Society Range.

In cooperation with the National Science Foundation

Landsat Image Mosaic of Antarctica (LIMA)

Printed on recycled paper
For most of us, Antarctica was at best a distant 

acquaintance. Now, with the Landsat Image Mosaic of 

Antarctica (LIMA), we are on intimate terms. In stunning, upclose and personal detail, LIMA brings Antarctica to life.

Explore this virtually cloudless, seamless, most 

geometrically accurate, and highest resolution satellite mosaic 

of Antarctica.

A team of scientists from the U.S. Geological Survey, the 

British Antarctic Survey, and the National Aeronautics and 

Space Administration, with funding from the National Science 

Foundation, created LIMA in support of the International Polar 

Year (IPY; 2007–08).

As the first major scientific outcome of the IPY, LIMA 

truly fulfills the IPY goals. LIMA is an international effort, 

supports current scientific polar research, encourages new 

projects, and helps the general public visualize Antarctica 

and changes happening in this southernmost environment. 

Researchers and the general public can download LIMA and 

all component Landsat scenes at no charge.

Discover How LIMA Was Created

Scene Selection

The team created LIMA from over 1,000 Antarctica 

scenes taken by the Enhanced Thematic Mapper Plus (ETM+) 

sensor since Landsat 7 launched in 1999. The selection process 

began with the team searching through 8,000 scenes with 0 to 

10 percent cloud cover. As much as possible, scientists chose 

adjacent scenes from a single Landsat pass over Antarctica 

because of the consistent sun angles and weather conditions. 

For areas without a cloud-free scene, over 15,000 more scenes 

were assessed for minimum cloudiness and for cloud-free 

portions of the scenes. Finally, areas with overlapping scenes 

were studied to select the best quality data available. For areas 

without any clear images, scientists used the least cloudy image.

Imagery from the Natural-Color, Pan-Sharpened LIMA (bands 3, 2, 1). Left: Oblique view of Ross Island with McMurdo Station at the tip of Hut 

Point Peninsula in the foreground. Right: Oblique view of McMurdo Dry Valleys. 

Left: Damocles Point on the east coast of Alexander Island at the base of the Antarctic Peninsula, with calved icebergs. Right: A slender 

glacier tongue feeds into Radok Lake, a 6-kilometer (4-mile) meltwater lake near the Amery Ice Shelf.
Scene Preparation

The LIMA team processed each Landsat scene with 

elevation data and sun-angle correction to ensure surface 

features were accurately represented. The sun’s angle in 

Antarctica gives the appearance of a setting sun. As Landsat 

passes over Antarctica, the low sun angle makes outer edges 

of the continent appear brighter than areas closer to the South 

Pole, so scenes have bright and dark areas. The team corrected 

for these inconsistent sun angles and shadows. Without this 

process, mosaicking would produce a patchwork effect.

Mosaic Process

The team used custom software to merge the processed 

Landsat scenes. Because of the extensive number of scenes 

available, the team stacked scenes, so almost all areas with 

cloud cover were overlapped with cloudless data from an 

adjacent scene. To eliminate a few noticeable seam lines along 

scene edges, the team trimmed scene boundaries to follow 

natural features where possible. Individual scenes were then 

combined into 25 blocks of merged data. The team combined 

and stored these 25 blocks as 5 virtual mosaics. This process 

avoided problems associated with maintaining and working 

with extremely large files (about 1 terabyte for each mosaic if 

actually merged together into one file). The virtual mosaics 

were then processed and output in 2-gigabyte GeoTiff files.

Explore LIMA and the LIMA Web Site

Discover the natural wonders of Antarctica by exploring 

each version of LIMA. Pan and zoom in to uncover areas of 

Antarctica never before seen with such clarity.

The View LIMA page makes it simple to tour the beautiful 

and haunting landscape of Antarctica with easy-to-use pan and 

zoom tools. Visit the Atlas of Antarctic Research map viewer 

for a more extensive exploration of LIMA with geographic 

information system resources (such as location names). The 

Download Mosaics and Landsat Scenes page features all the 

versions of LIMA, the original and processed Landsat scenes, 

and previous mosaics of Antarctica for quick tiled downloads at 

no charge.

The map viewers display the mosaics and Landsat scenes 

in polar stereographic projection with Web Map Service. All 

GeoTiff tiled downloads include Federal Geographic Data 

Committee compliant metadata.

Find a wealth of other resources at http://lima.usgs.gov 

including USGS Antarctic maps and products, the spectacular 

LIMA poster from the British Antarctic Survey, as well as a 

digital library of Antarctic and IPY research and information.
Natural-Color, Pan-Sharpened LIMA (bands 3, 2, 1)

combines Landsat ETM+ bands 3, 2, and 1 (red, green, and

blue of the electromagnetic spectrum) at 30-meter spatial 

resolution with the 15-meter, grayscale panchromatic band 

8. Pan-sharpening maintains the natural-color information 

valuable for field recognition in Antarctica; but with the higher 

spatial resolution, features in the snow and ice will appear more 

clearly defined. Through resampling techniques, each pixel in 

the 30-meter, natural-color bands is divided into four smaller 

pixels and then merged precisely with the pixels in the 15-meter 

panchromatic band. With each pixel representing 15 meters by 

15 meters (49 feet by 49 feet), scientists can identify features 

roughly the size of half a basketball court.

False-Color, Pan-Sharpened LIMA (bands 4, 3, 2)

incorporates infrared data, allowing scientists to more clearly 

discriminate between ice and snow. This version merges 

Landsat ETM+ bands 4, 3, and 2 (near-infrared, red, and green 

of the electromagnetic spectrum) at 30-meter spatial resolution 

with the 15-meter, grayscale panchromatic band 8.

Enhanced Versions of LIMA use different stretches to 

bring out features in Antarctica that would not normally be 

visible. In the same way that sunglasses soften the glare, these 

enhancements tone down the brightness of the entire image 

while preserving the color balance.

Learn more about the other LIMA products at

http://lima.usgs.gov including the Center-Filled LIMA, the 

Original Landsat Scenes (National Land Archiving Production 

System format), the Processed Landsat Scenes (16 bit), and the 

16-bit Intermediate LIMA.

For more information about LIMA and

http://lima.usgs.gov, please contact:

Customer Services

U.S. Geological Survey

Center for Earth Resources

 Observation and Science (EROS)

47914 252nd Street

Sioux Falls, SD 57198-0001

Tel: 800-252-4547

Tel: 605-594-6151

TDD: 605-594-6933

Fax: 605-594-6589

Email: custserv@usgs.gov