Data Formats and Naming Conventions

Fast Format

The "EOSAT Fast Format Rev. C" consists of one ASCII header file and one simple binary image file for each band. In the case of PAN or LISS-IV Mono there is one header file and the corresponding image file. In the case of LISS-III you will find one header file and up to 4 separate image files, one for each band. The ASCII header includes the image size (number of pixels per line and number of lines), image location (4 corner co-ordinates and one centre co-ordinate, path, row), acquisition parameters (date, sun elevation, sun azimuth, gain settings) and some technical parameters related to the processing (product code, etc.).

Due to the simple internal structure of the Fast Format, the binary image files can easily be ingested by virtually any image processing software.

Super Structure Format

The "Super Structure Format" has a much more complex structure than the Fast Format. A typical data set consists of a "volume directory file" (which includes a short description of the data product and a number of pointers and corresponding descriptors), one "leader file", one or several "image data files", one "trailer file" and one concluding "null file". Other than the Fast Format, the Super Structure Format contains information related to ephemeris and spacecraft attitude. The image data files (generally one for each band for products processed by Euromap) are not just binary raw files, but consist of a "file descriptor record" and one "image data record" for each line of the image. The image data records encapsulate the data of one image line and consist of record sequence numbers, record types, length of the record, scan line number, band number, the image data of the scan line, and some spare bytes.

Due to the specific internal structure of the Super Structure data format, the image processing software is usually required to be equipped with a special importer module.

Naming Conventions

Unfortunately there are no naming conventions for IRS-1C and IRS-1D products defined in the Fast Format and Super Structure Format documents. As a consequence different ground stations follow different rules.

Distribution Media

IRS data products are offered on the following media:

• CD-R (default), ISO 9660 file system with Joilet and Rockridge extensions, 650 MB
• DVD-R, ISO 9660 file system with Joilet and Rockridge extensions, 4.7 GB
• USB Hard Disk, external hard disk drive using FAT32 file system
• Online, via Internet using the FTP protocol

Please note that delivery on hard disk is only offered for large amounts of products. You will be able to choose your preferred media on our order forms.

Downloads

The table below lists all documents regarding file formats and naming conventions available for download.

1) Different processors are in use for the production of IRS-P6 and IRS-1C/1D data products at Euromap. Even so the document describes also a format for IRS-1C/1D, only the document under the column 'IRS-1C/1D' is applicable for IRS-1C/1D products processed by Euromap.
2) See also the Errata for IRS-1C/1D Fast Format below.
3) See also the Errata for IRS-1C/1D Super Structure below.
4) The IRS-P6 document describes the GeoTIFF for IRS-P6 data products as generated by the DPGS processor and offered by some ground stations. However, the band separated GeoTIFFs delivered as part of the Euromap Ortho Kit for IRS-P6 are not generated by the DPGS, are very basic, and a describing document does not exist.

Errata for IRS-1C/1D Fast Format

Page 9: Please use the following to calculate Northing and Easting of any pixel within the image:

	    PE = ((NP-P)(NL-L)ULE + (P-1)(NL-L)URE + (NP-P)(L-1)LLE +
	         (P-1)(L-1)LRE) / ((NP-1)(NL-1))
	    PN = ((NP-P)(NL-L)ULN + (P-1)(NL-L)URN + (NP-P)(L-1)LLN +
	         (P-1)(L-1)LRN) / ((NP-1)(NL-1))
		

Errata for IRS-1C/1D Super Structure

Page 24: The value is given in radiants:

	    44    526-541      N   Cross track FOV (radiants)-F16.7