This page allows for the download of the GDAL software for various platforms.
Download and install as per instructions to allow the execution of GDAL commands as part of the PATH variable.
Once the GDAL utility programs are installed one can execute a set of
commands in the command shell to convert SIR file images to the
geotiff formats. The gdal_translate program inserts coordinate
reference details into the header of capable files (e.g. GeoTIFF).
A utility program, sir2geotiff.c, when
compiled and run locally, automates the following process.
Instructions for compiling and running this utility program are in the
To manually create a geotiff image, first create a full scale GIF or
BMP image from the SIR file. Use a one-to-one pixel version. This
can be done with sir2gif, sir2bmp, or sir_util. Source code for sir2gif,
sir2bmp, and sir_util can be compiled for most platforms. (sir_util.exe
is available as a precompiled windows executable.)
Then, run gdal_translate to create a .tif file that has the geotiff
header. You will have to input the the corner coordinates (in meters)
of the SIR image. The required gdal_translate projection parameters
and corners can be determined using the sir_util tool.
Consider conversion of a QuickSAT slice Arctic image
(qush-a-ArcYY-ddd-ddd.sir). Examinging the .SIR file header, .SIR
image is in polar stereographic form with reference latitude 70 deg
and vertical longitude -45 deg. The image corner coordinates are at
-3400000 3406275 3406275 -3400000 km. (While all q*s*-*-Arc* have the
same header, images of other areas will have different corners and
projections). In this example a full scale .gif image is first
created using sir2gif or sir_util, then gdal_translate is run with the
image file as input, i.e.
gdal_translate -a_srs "+datum=wgs84 +proj=stere +lat_ts=70.0 +lat_0=90 +lon_0=-45"
-a_ullr -3400000 3406275 3406275 -3400000 -of GTiff -co compress=LZW