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IRS
Products
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Processing Level
IRS data are typically available processed
as System Corrected. This means that the
products are radiometrically and geometrically
corrected to the user-specified parameters
including output map projection, image
orientation, and resampling kernel (see
after).
Geometric Corrections include Earth rotation,
Earth ellipsoid and map projection, satellite
attitude and internal sensor distorsion
From Euromap products are also available
corrected only Radiometrically (not geometrically)
for PAN and LISS-III.
System Corrected images can be produced
with 2 different orientations: path oriented,
displaying on the same rows the satellite
acquisition scan lines, or map oriented,
with north-up display.
From Euromap it is possible to have for
LISS-III a synthetic blue band. Euromap
has developed a model to derive a synthetic
blue band on the basis of the 3 recorded
LISS bands covering the green, red and
near IR portion of the spectrum and a library
of signatures. The resulting natural color
renditions have proven to be of excellent
quality and are particularly useful for
the production of IRS PAN/LISS merged scenes.
The blue band can be ordered as an option.
No atmospheric corrections are applied
to the images.
Resampling algorithm
Level 1G images, during the geometric correction,
are resampled to a regular output grid.
The resampling kernel specifies how the
input pixels are sampled: how many and
how they are weighted. The available algorithms
are:
Nearest Neighbour: in the transformed geometry
the radiometric value of the output pixel
is set equal to the value of the nearest
input pixel in the original geometry. This
algorithm preserves at its maximum the
original radiance values.
Cubic Convolution: in the transformed geometry
the radiometric value of the output pixel
is interpolated using the values of its
16 nearest neighbours in the original geometry.
This algorithm produces a better looking
image, but changes the original satellite
radiometry.
IRS
products and formats by Ground
Station
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Map Projections
and Ellipsoids
UTM/WGS84 are available from all ground
stations. |
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