Institute Ice Stream

Institute Ice Stream

Access Data

Image Information

Velocity data were derived from the Landsat scenes listed below. To view image data select Velocity Map or Data Set Map, or use the links on the overview image.

Raw Images

Satellite Image ID # Path/Row Date Acquired
Landsat 5 5190120008604710 190/120 16 February 1986
Landsat 4 4190120008901510 190/120 15 January 1989

Corner coordinates for Institute Ice Stream velocity reference image:

Number of Lines: 6335
Number of Samples: 6728

Upper Left -80.23413S -70.23627W
Upper Right -81.80079S -65.72160W
Lower Left -80.71871S -79.55822W
Lower Right -82.38347S -76.68984W

Data Set Information and Access

Both image co-registraion and velocity vectors are derived using the IMCORR software developed by Scambos et al. 1992 (see Related Publications). Typical co-registration errors are a few pixels. Because this error is constant for any image pair, it is treated as a systematic error within that image pair. Each cross-correlation match has an additional random error, typically about 0.3-0.5 pixels (Landsat resolution is 28.5 meters per pixel). IMCORR measures velocity as displacement divided by time separation, therefore, velocity errors scale as the inverse of the time interval. However, as time separation between the image pair increases, changes in the ice surface (e.g. crevasses, orientations, dunes, shear strain) result in fewer successful correlations.

While error in speed and error in bearing are reported, a more realistic error estimate is the combination of a systematic error of 1.5 pixels (42.75 meters) divided by time separation and a random error of 0.5 pixels (14.25 meters) divided by time separation. The reported speed and bearing errors are derived from the strength of the IMCORR feature correlation for each vector, and are therefore more related to precision than accuracy.

Access the tabular velocity data for the Institute Ice Stream