By default it is described in GeoTIFF format, consisting of:
- a TIFF part, as TIFF is the most widely used image format in the world, recognised by all software on the market and easily integrated.
- and a Geo part, recognised by all geographic information processing software. It adds georeferencing information for the image file (coordinates in the upper left-hand corner of the image and pixel size) to the basic TIFF file and may also describe the map projection used and its corresponding geographic system.
This is written in XML. XML, similar to HTML, is more highly structured and allows users to create their own keywords with their corresponding values. It can be read directly by standard Internet browsers and can be linked to an XSL style sheet which sorts and does the HTML layout of the information contained in the XML file.