The BYU-MERS "sir" image
format was developed by the Brigham Young University MERS Laboratory
to store images of the earth along with the information required to
earth-locate the image pixels.
A "sir" file consists of one or more 512 byte headers containing
all the information required read the remainder of the file and
the map projection information required to map pixels to lat/lon
on the Earth surface.
Image pixel values are generally stored as 2 byte (high order
byte first) integers though can be stored as bytes or IEEE floating
point. The latter is not portable to all machines and so is not
recommended but is available. Scale factors to convert the integer
or byte pixel values to native floating point units are stored in
the file header.
The origin of the images is in the lower left corner of the displayed
image. The earth location of a pixel is identified with its lower-left
corner.
The standard sir format supports a variety of image projections
including:
- Rectangular array (no projection)
- A rectangular lat/lon array
- Two different types of Lambert equal-area projections which
can be use in both non-polar and polar projections
- Polar stereographic projections
- EASE grid polar projection with various resolutions
- EASE global projection with various resolutions
SIR image format links:
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