A while back a website was discovered which collects and archives ship's meteorological reports. The site accumulates around 1Mb of data each day, storing it in its raw, coded format as one great big text file..Would it be possible to gain some insight into the movement of ships by decoding these reports and plotting them on a nautical chart? This is the story of the Ship Tracker project.  

The Code
Ships use synoptic code FM13 for their reports, not for secrecy, but to compress the data for radio transmission.  As you can see below the observation is mostly groups of five numbers.   GBTT 01063 99316 30168 41998 31109 10167 20141 40067 58017 70300  80004 22285 00120 20302 318// 40605 80152=   A search of the web uncovered a Ship's Code Card allowing the reports to be translated. With the aid of the card this example is from the Queen Elizabeth II radio callsign GBTT on 1st April at 6am when she was 31.6 south 16.8 east.

AWK
Reports are taken every six hours and midnight, 6am, noon and 6pm GMT. These are sent in by morse, radio telex and INMARSAT to meteorological centres. . Reports were downloaded for a several days to see if there was a consistent pattern to the layout. AWK, a  tool which which Lynix users will be familiar proved invaluable and provided several important insights. The first insight was that there was a lot of duplication. This is almost certainly because meteorological centres freely share information - so a report radioed to Bracknell may be routinely copied to Geneva and Washington. Geneva sends it a second time to Washington. Any program would have to weed out duplicate entries. AWK provided another insight - the senders did not consistently use a standard layout - some embedded spurious form-feeds, characters and missed out large chunks of the report.  A clever bit of programming would be required to identify the beginning and end of each report - reject it if it was duplicate or too badly corrupted - yet let through as many reports as possible for final decoding.  

From Russia with love
Delphi - a derivative of Pascal  was chosen as the language to undertake the project. However  the pattern searching and matching provided by AWK is absent from the Delphi language and was sorely missed. Fortunately a Russian programmer had recently created a set of GREP routines in Delphi - making them freely available on the Delphi Super Site in Warsaw.  

GREP
GREP, another Lynux tool  is the pattern matching part of the AWK language.We've all used the junior version in DOS and Windows typing G*.* to find all files beginning with the letter G and so on. GREP and AWK allow more sophisticated searches, you simply supply the pattern to search for and they do the rest. For example the group containing the ship's latitude always begins with '99'  can be extracted by looking for this pattern:   '99[0-9]{3}';   This pattern means nine, nine then exactly three numbers in the range zero to nine.   The longitude group always begins with 1,3,5 or 7 followed by four numbers:   '[1357][0-9]{4}'   Or in  words 1 or 3 or 5 or 7 followed by four numbers in the range zero to nine.
Looking for patterns without the aid of a GREP module would entail a lot of head-scratching.  

Plotting the information

After a lot of searching a GIF mercator chart of the world was located to use as the chart on which to plot the ships positions. Thanks to the GREP routine it was possible to spot valid met reports amongst the masses of data downloaded daily. By now several days of data had been accumulated.. The data was spread across two databases - one containing the callsigns and particulars of ships of interest - and a second database containing their six-hourly position reports. The program was initially set to watch only for UK registered ships. These would have radio callsigns beginning with G or M. This was necessary to limit the masses of data which would otherwise hamper testing the system.  

Trial Run
Lots of bugs to fix, but It worked! There was the track of the research ship the RRS Charles Darwin, around the coast of Ireland and down the bay of Biscay. The track slightly off due to the effect of Mercator projection - a fix would be found - but that could wait.   Extending the Search
As development of the program  progresses, ideas for more features occur - for instance - why not have 'callsign templates'. With these it would be possible  to watch for and record data from any ship or a group of ships. This was quite timely because of imminent sailing of the new cruise liner Aurora from Southampton and the maiden voyage of the Irish famine Replica ship - the Jeanie Johnston. A friend in the know found the callsign of the Aurora - GBSS - so this and a template to detect all Irish ships have been created. When she or the Jeanie set sail the program will start to track them.  

South Pacific
It is fascinating to watch the movement of ships day by day. There for instance was the track of a ship eastwards down the pacific, altering course slightly after Tahiti and onward to New Zealand. It proved to be a fast container ship named after our local river, the Foylebank.     Mystery Ship
From the world view the program affords, a mystery ship was spotted about 1,000 miles of the coast of Chile slowly steaming north. Unlike the others it was not on a fixed course, rather it meandered this way and that. It is the S0ren Larsen, UK registered, but possibly Norwegian owned. An educated guess is that it might be a fish factory ship or a whaler. By Thursday 11th May it was close to the Pacific entrance to the Panama canal. If you want to see her transit the canal and decide for yourself take a look at the Panama canal web camera at
http://www.pancanal.com

Top software on offer this month includes:

 IBM World Book '99 - One of the better multimedia encyclopaedias
  FreeSpeech '98 - A top quality speech recognition package.
  The Ordnance Survey Atlas of Great Britain.
  The Time Magazine Almanac of the 20th Century - An enjoyable reminder of times past.
  Eudora Mail - Possible the best email package you can buy and it's free.
  4th dimension - A powerful RAD tool for database application development.
  Command Antivirus - Includes a year's free updates.
  Catz 3 - The ultimate desktop pet.
  BeOS 5 - A leading edge PC operating system.
  Sidekick 99 - Organiser software.
  NumberChange - Updates Outlook contacts for the 'Big Number' dialling code changes.
  PGP - The industry standard for encrypting data to be sent over the internet.<BR>

Why not visit Cover CD now and subscribe to their Newsletter.

Looking for a niche market to exploit and make a bob or two for yourself by selling on the internet? Here is a friend of ours who is doing just that in Bangor. Derek has an innovative site selling old and rare books of Irish/Ulster interest. He dispatches books worldwide and even has a free email catalogue. You can visit him at:
http://www.booksulster.com
Here is a snippet from this month's finds:

32. STEVENSON, George.: A Plea for the Covenanted Reformation in Britain and Ireland. Glasgow: Young, 1824 (2nd edn, corrected & enlarged). 95pp. Disbound. Bound with `Address of the United Synod to the People under their Charge, occasioned by the late Union of the two larger Bodies of Seceders'. Published in Glasgow, 1820. 23pp. The title page and following advertisement page have been torn at top left corner, but are complete. {Price in Pounds Sterling = £38.00} Stock ref 3782. £38.00

33. STRAIN, E. H.: A Man's Foe's. London: Ward Lock, 1896 (Pop. Edn). x, 467pp + ads. Illus. Blue cloth. [Novel based on the conflict in Ireland in 1689, including the Siege of Derry]. Binding a bit rubbed and worn at extremities. The name `E.H. Strain' is hand-written on title page, so may be author signed. {Price in Pounds Sterling = £10.00} Stock ref 3778. £10.00

34. TAYLOR, A. R.: Willowfield Parish Church, Belfast, 1872-1972. Belfast, 1972. vi, 165pp. Illus. Wraps. [Includes Roll of Honour of those from the parish who died in The Great War]. Covers creased and a bit soiled; some page corners creased at bottom. Good copy only. {Price in Pounds Sterling = £5.00} Stock ref 3780. £5.00

35. TRANSPORT.: Report of the Transport Tribunal. Belfast: HMSO, 1952. 76pp. Wraps. Folding route maps and plans. Includes information on the now abandoned Comber line, the Belfast-Bangor line and the Belfast Central railway. Wraps are a bit soiled and are splitting at spine fold. {Price in Pounds Sterling = £10.00} Stock ref 3781. £10.00