Understanding Map Projections
Understanding Map Projections
Understanding Map Projections
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SPACE OBLIQUE MERCATOR<br />
DESCRIPTION<br />
This projection is nearly conformal and has little<br />
scale distortion within the sensing range of an<br />
orbiting mapping satellite such as Landsat. This is the<br />
first projection to incorporate the earth’s rotation<br />
with respect to the orbiting satellite. For Landsat 1, 2,<br />
and 3, the path range is from 1 to 251. For Landsat 4<br />
and 5, the path range is from 1 to 233.<br />
Used to tie satellite imagery to a ground-based<br />
planar coordinate system and for continuous<br />
mapping of satellite imagery.<br />
Standard format used for data from Landsat 4 and 5.<br />
PROJECTION METHOD<br />
Modified cylindrical, for which the central line is<br />
curved and defined by the ground track of the orbit<br />
of the satellite.<br />
LINE OF TANGENCY<br />
Conceptual.<br />
LINEAR GRATICULES<br />
None.<br />
PROPERTIES<br />
Shape<br />
Shape is correct within a few parts per million for<br />
the sensing range of the satellite.<br />
Area<br />
Varies by less than 0.02 percent for the sensing range<br />
of the satellite.<br />
Direction<br />
Minimal distortion within the sensing range.<br />
Distance<br />
Scale is true along the ground track and varies<br />
approximately 0.01 percent within the sensing range.<br />
LIMITATIONS<br />
Plots for adjacent paths do not match without<br />
transformation.<br />
USES AND APPLICATIONS<br />
Specifically designed to minimize distortion within<br />
the sensing range of a mapping satellite as it orbits<br />
the rotating earth.<br />
84 • <strong>Understanding</strong> <strong>Map</strong> <strong>Projections</strong>