The Chesapeake Bay in the Nov 2, 1982 Landsat image
The Nov 2, 1982 Landsat image covers much of the Chesapeake Bay.
The Thematic Mapper bands may be combined in various ways.
The following image shows every pixel of bands 4, 3, and 1 combined
as red, green, and blue to give a color IR view.
IR (4,3,1), resulting image size: 800 x 800,
starting pixel = (4160,1020), subsample factor = 1.
Some sediment is visible in the bay. Hart-Miller Island
is an artificial island which is being filled by harbor dredgings,
a small plume of sediment is seen escaping.
Some Thematic Mapper bands show features in the water areas better
than others. In the following image bands 3, 2, and 1 are used
as red, green, and blue (instead of 4,3,1).
It is possible to process the image to better show the sediment
in the water. However, scaling to bring out water details gives
a poor scaling for land features. One way around this is to scale
land and water differently. Band 5 of this image may be
thresholded to separate land and water.
This was done to allow separate scaling for land and water in the following
image. A black border was inserted between the regions of the different
scalings.
Vis (3,2,1), resulting image size: 800 x 800,
starting pixel = (4160,1020), subsample factor = 1.
A number of long thin ship wakes are visible in this image.
The water portions of the image were stretched more strongly than
the land and show some of the artifacts in the data.
With image filtering techniques it may be possible to reduce these
artifacts somewhat. The land areas
show roughly the true color, that is, what the eye would see.