The system works under UNIX, for the time being Linux. All software is manufactured by Olex AS, except the tide calculations which are handled by XTide2 The system is never switched off. It continuously upgrades its own world map. The measured data are always ready for use. As time goes by, the amount of details will exceed the official paper charts. Only common navigation instruments are required. The quality of the depth and position data are good even with the least expensive equipment. The system is multilingual.
Digital conversion of the charts
The system runs with electronic vectorized charts, originally in S57, S63 and NSKV format. The charts are organized in rectangular cells, each one covering a specific area along the coastline. Effective use of digital charts requires fast computer processing. The chart cells are converted into an internal compact format, where they are kept in different crude scaling levels. To achieve this, the coastline and other details have to be recalculated and reduced. In this way the time and memory requirement of the visualization program are kept at a fairly limited and constant level, whether it is focusing on the whole country or just one single island. The screen will not be filled up with unnecesery information. In the crude scaling level, the visualization program scales the charts in several steps. In this way a fine and seamless interactive scaling is achieved, without any annoying details related to the organisation of the cells.
Calculating the shape of the seafloor
The system reads observations in four dimensions - time, depth, longitude and latitude - and upgrades a database where the sea floor is divided into squares of any resolution. The default resolution is 5X5 meter, an adjustment of today's inexpensive GPS equipment, but the user can easlily create new sea floor databases in any resolution down to a few cm. The squares may be considered as a grid covering the surface of the hole earth. They contain a depth value which are either measured, calculated or unknown. Repeated measurements of the same square will improve the depth value. New measurements will also result in a recalculation of the unmeasured squares in some radius from the considered point. The squares are further organized into cells, which again are parts of bigger cells meant for other scaling levels. The larger squares represents the mean depth of the containing smaller squares. The cells are stored in such a way that the system easily reads the relevant information.
Linux is a registered trademark belonging to Linus Torvalds.
XTide 2.0 Copyright 1998 David Flater.
Olex Copyright 1999 Olex AS.
