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APPLICATION OF LANDSAT MOSAICS FOR THE COMPILATION
OF SMALL SCALE GEOMORPHOLOGIC MAP OF YUKON TERRITORY
A.B.KESIK
DEPARTMENT OF GEOGRAPHY, UNIVERSITY OF WATERLOO
WATERLOO, ONTARIO, CANADA
Characteristic of Landsat Mosaics for Yukon Territory
Landsat Mosaics for Yukon Territory,Canada, have been
compiled in 1975 by the Canada Centre for Remote Sensing,
(CCR8) and Topographic Survey. Mosaics for the Territory
belong to the set which covers the whole country (Kesik,1975)
Mosaics are based on the Landsat 1 images generated by
the Multispectral Scanner. For the Yukon Territory only ima-
ges from channel 6, with spectral range 700-806 nm, have been
used for mosaicing. The images were recorded in period 1972-74
Selection of the images for mosaicing took into account
minimum of ice, snow and cloud cover.Limited number of good
images caused application of those which show frozen lakes,
snow cover and offshore ice. To eliminate clouds, segments
of successive images have been used to compose one scene.
Images used for mosaicing were corrected for earth's
rotation. Such a correction was done at CCRS centrum in the
later stage of Landsat operation. Early, noncorrected for
earth's rotation images were reproduced,segmented and composed
with required tolerancy od error.
It is worth to mention that Landsat MSS data is subjected
to many distortions.Some of the errors have dynamic character
with unpredictable magnitude and direction, other are syste-
matic and easy for correction. Interaction of dynamic and
systematic errors results in total distortion, changina from
image to image.
Distortions due to earth's rotation, scan nonlinearity and
processing errors were removed at CCRS. Remaining residual
errors are less significant and not important for the scale
of Landsat mosaics.
Precise processed MSS data has, according to Colvocaresses
(1974), sufficient resolution and geometric fidelity to treat
it as a true map projection - Space Oblique Mercator, Tt is
unique projection which may be could be used for mosaic
compilation, but the relevance of such a projection is limited
by the lack of general or thematic maps produced in this
projection.
All existing Landsat mosaics produces in different count-
ries have been constructed on the base Of projection applied
to the general maps. The technique of image mapping( Tomlinson,
1972) is used as the most practical,
In Canada, Lambert's Conformal Conic Projection was used
for matching MSS images. This projection is used in Canada
for 1:1,000.000 maps. Due to the characteristic of Lambert's
projection compiled area sheets of mosaics could be joint
only in east-west direction.
eed