In an attempt to reverse-engineer the file format of D-Sat 1 I discovered that the satellite images are stored using the Lightning Strike image format. There exists little information about that format and no current software to open and view the files. The goal of this web site is to collect as much information as possible about the file format and associated resources to ultimately enable an implementation of an open source image viewer for those files.

About the name

According to archived web pages and the ArchiveTeam wiki the image format is called “Lightning Strike”. The wiki states the MIME type to be “image/cis-cod”. The three letters “CIS” are the first three bytes of each image file (a magic number) and at the moment it is not clear, what they stand for. The files typically have the file extension “cod” which very likely stands for “coded” (image). For the purpose of this web site I have decided to use the more technical term “CIS/COD” which is derived from the MIME type and refers to the two main indicators of the image files.

Further reading

At the moment the best overview is given by the ArchiveTeam wiki and a good starting point for further reading are the following blog posts:

  • Finding the tiles – where we first discover that CIS/COD is used to store satellite images in D-Sat 1.
  • Learning about the image format – which provides first results of some (mainly Internet Archive) research on finding resources describing the image format.
  • Viewing tiles with Firefox – which is a practical guide on how to view (and convert) images with an old Windows version of Firefox.
  • Fragmenting the tile data – where I tried to understand the arrangement of the data for the wavelet sub-bands.

On this site, the documentation page currently mainly lists information about the known software and DLLs and the resources page provides access to a magic file for the file command and a file format description for Kaitai Struct.