This document briefly describe sir_util.c and sir_util2.c

These C-language programs are designed to enable viewers to inspect
BYU .SIR format files and generate browse images from the files
Source code is available on this ftp site 
ftp://ftp.scp.byu.edu/software/sir_util/
ftp://ftp.scp.byu.edu/software/c/
while pre-compiled windows executiable programs are available at
ftp://ftp.scp.byu.edu/software/sir_util/windows_utils/sir_util.exe
ftp://ftp.scp.byu.edu/software/sir_util/windows_utils/sir_util2.exe


The BYU-MERS "sir" image format was developed by the Brigham Young
University (BYU) Microwave Earth Remote Sensing (MERS) research group
to store images of the earth along with the information required to
easily earth-locate the image pixels. The binary SIR file includes a
header with all the information to geolocate each pixel in the
image. The origin of the .SIR file image is in the lower left
corner. The earth location of a pixel is identified with its
lower-left corner. Most sir files are in either polar stereographic or
Lambert equal-area projections, though some EASE grid images are
regularly produced.  


Two programs are available

sir_util.c
sir_util2.c

Both are self-contained once linked to the C SIR library.  They should
compile on most platforms.  sir_util.c supports only greyscale images and
export to BMP and GIF images while sir_util2.c supports user-defined color
tables and exports to TIFF and GeoTIFF files.  Note that GeoTIFF conversion
is only available for polar stereographic or Lambert equal area projection
files; otherwise, the output images are conventional tiff images.

Both programs require specification of the input .SIR file which can
be done from the command line or interactively entered.  Afterward,
users select from menu of options to print the SIR file header, 
print projection information, locate pixel or lat/lon positions,
print image values, generate browse image files, or dump the values
to ascii files.

To link the programs use something like (after appropriately 
setting the SWAP parameter in sir3.h)

cc -O -I ./ -o sir_util sir_util.c sir_io.c sir_geom.c sir_ez.c

cc -O -I ./ -o sir_util2 sir_util2.c sir_io.c sir_geom.c sir_ez.c

Note: a bug in writing polar stereographic geotiff files from sir_util2
was fixed on 3 Oct 2012.