Hello Guest July 16, 2024, 10:08:20 *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
 
Pages: [1]   Go Down

Author Topic: Accuracy of geographical coordinates  (Read 5276 times)

Fernando_Pastor

  • Forum member
  • Posts: 9
Accuracy of geographical coordinates
« on: February 28, 2009, 18:22:25 »

Hello,

First of all I’m a fan. Congratulations for a great work.

I would like to know if it is possible to improve the Coordinates System of the different (great and beautiful) scenarios on Ship Simulator 2008. I don’t know if you are using a specific Coordinates System or not, but I think that the one that you are using is arbitrary and not enough accurate. I would like to use my nautical charts at the same time with the game.

Another thing: It could be possible implement a magnetic compass (for example with the binoculars) in order to get some bearings from the scenery? Furthermore, it will be great if there were much more nautical aids, like lighthouses buoys and other aids for practice the navigational skills of the players.

When do you arrange the localization of the game in Spanish? Maybe I can help with that. As you can see my English is not too good but my Spanish is.

Capt. Fernando Pastor
Logged

Ballast

  • Global Moderator
  • Posts: 3490
Re: Accuracy of geographical coordinates
« Reply #1 on: February 28, 2009, 21:52:35 »

The used coordinates system is pretty accurate, if not precise. I assume they used WGS '84 as chart datum.

I also mentioned it already a few times on SSF, that some more navigation instruments would be nice. ARPA radar, gyro compass, posibilty to take bearings and to plot it in the chart, ECDIS with voyage planning etc etc. Yes indeed, there is a GPS position shown in the HUD, but it's so much nicer to calculate your position by other things as mentioned above. That is what seperate us from the button pushing wannabe captain (including the hat!) who sails his white and shiny yacht to Cannes (metaphorically speaking  ;))

Logged
It's the crew that makes the difference

Fernando_Pastor

  • Forum member
  • Posts: 9
Re: Accuracy of geographical coordinates
« Reply #2 on: March 03, 2009, 12:37:30 »

Really Ballast?

I’ve been calculating the differences between coordinates of some environments using Google Earth (WGS84 datum). That is not as simple as a coordinate’s conversion error between different datums (ED50, ETRS89… and WGS84). Differences are too big in all cases, I still tihnking that is an arbitrary error.

Rotterdam (Erasmus bridge)
Scenario coord.   51º58.9’N – 4º9,7’E
WGS84 coord.   51º54,5’N – 4º29,3’E   
Error 12,9’

New York (Brooklyn Bridge)
Scenario coord.   40º41,3’N – 74º6,7’W
WGS84 coord.   40º42,3’N – 74ºW   
Error 5,2’

Solent (VTS Centre)
Scenario coord.   51º4.5’N – 1º51’E
WGS84 coord.   51º53’N – 1º23,6’E   
Error 20,8’

Other scenarios.  Marseille :15,5’ Hamburg : 2,3’; San Francisco: 24,2’

In my humble opinion, someone who loves the navigation as much as the boats needs at least 5 things for fall in love with this game too (this phrase too gay isn't it? ;D):

A magnetic compass for take bearings form the environment’s items (mandatory).
The accurate georeferentiation of the different items on the scenarios.
Nautical aids on the environments and correctly placed on it as: lighted buoys, lighted marks, and light characters in order to recognize them (colour, phase, period, sector)
Lights on scenarios at night (Quite scary navigate for them at night  :o)
A better cartography with the possibility of print all the charts. (That includes Limits, areas, routeing measures, arrows for traffic flows, and so on)

There are another things, as you said, but for me those are the most important. Think about this: Why do I need a sophisticated 2000€ plotter in a taxi boat, a tugboat or a hydrojet  ???? I need lights, marks and a compass, like always.

Capt. Fernando Pastor
PD: Sorry for my horrible English
« Last Edit: March 03, 2009, 21:44:25 by Fernando_Pastor »
Logged

mvsmith

  • Guest
Re: Accuracy of geographical coordinates
« Reply #3 on: March 03, 2009, 15:54:03 »

That the GPS coordinates on the HUD are not accurate is well known, and has been discussed on this forum over a year ago.

This simulator is an entertainment version of the professional training simulator developed by VSTEP. There are technical differences between the two. The most obvious one being about 4000 Euros.

The compass on the chart is either a gyro compass or a magnetic compass, as appropriate to the ship.
Large merchant ships would be expected to have a gyro compass and repeaters. Small boats and yachts would be expected to have magnetic compasses—as would Titanic.
It would be up to the user to interpret the compass and the chart in the correct context.


The Pro version has a pelorus for taking compass bearings. That feature has not yet found its way into SS NP.
« Last Edit: March 03, 2009, 16:06:03 by mvsmith »
Logged

Fernando_Pastor

  • Forum member
  • Posts: 9
Re: Accuracy of geographical coordinates
« Reply #4 on: March 03, 2009, 21:40:39 »

Sorry if this is an old discussion.

I think that have correct latitude and longitude is secondary if I could print the environment chart form the game and take bearings from the scenery to it.

In fact to have the latitude and longitude near the shore is absolutely useless. Do I have to spend 5 minutes doing dead reckoning calculations when in 5 minutes I could run aground? It has no sense. Furthermore if I have a plotting chart I don’t need the geographical coordinates at all.

But I need a compass. I think that is compulsory for improve the game. One simple hand bearing compass or a binocular with a compass, not only for knows my position quickly but for safety too: those other boats are crazy, man!  ;D They don’t respect the regulations :police:. If I know that they are in a collision course I can avoid them at last!



I would like to see that implemented in a game that is an amazing game, besides their professional applications, but 98% near the perfection.

Fernando
Logged

kuusuru

  • Forum member
  • Posts: 83
Re: Accuracy of geographical coordinates
« Reply #5 on: March 03, 2009, 22:40:10 »

But I need a compass. I think that is compulsory for improve the game. One simple hand bearing compass or a binocular with a compass, not only for knows my position quickly but for safety too: those other boats are crazy, man!  ;D They don’t respect the regulations :police:. If I know that they are in a collision course I can avoid them at last!

How does having a compass help you avoid collisions?  Last night I did the "Fisher follows fish" mission which offers plenty of collision avoidance practice, and I don't think a compass would have helped.  Especially in the open sea, when she's routinely rolling -25 to +25, and you're having to focus on the wheel and waves to steer anything like a straight course, I don't think you've the luxury of swanning around on deck taking bearings and doing calculations.

And even if you plot a vessel's course and speed, they are subject to change, often in a way which does not help you  :)
Logged

mvsmith

  • Guest
Re: Accuracy of geographical coordinates
« Reply #6 on: March 03, 2009, 22:59:32 »

For the purpose of deciding whether a vessel is on a collsion course with you, a compass is not necessary. You are interested in whether its relative bearing is changing. You can watch it through the fixed binoculars. You can detect small changes by placing the mouse pointer on it.
Logged

TerryRussell

  • Guest
Re: Accuracy of geographical coordinates
« Reply #7 on: March 03, 2009, 23:18:25 »

To add to that, If you observe a vessel over a period of time and its relative bearing does not change, then either you are both stationary, or you're going to collide. No compass required.
Logged

Traddles

  • Global Moderator
  • Posts: 5934
Re: Accuracy of geographical coordinates
« Reply #8 on: March 03, 2009, 23:29:30 »

For collision avoidance checking I just use camera 1 from a small distance away and line up through my bridge with the possible offending vessel. If the other vessel is drawing ahead she will cross ahead of you, if astern she will cross astern. If the bearing stays constant then collision is imminent. As Marty says, it is relative bearings which matter in this scenario. Of course if the other vessel changes course it is a different matter. Generally though, in the game, AI traffic sails at a steady speed so it is only course fluctuations which affect potential danger. Also, at night, which side light is showing can be an aid, As we used to say "green to green or red to red, perfect safety, go ahead". danger lurks in a red to green or green to red situation.
To kuusuru's point,
On a real ship in real sea conditions having a compass is VITAL. When I was taking my oral exams for my tickets, one of the favourite questions was:- "If you see a single white light at night what do you do?" I was asked that same question for 2nd mates exam, for mates exam and for masters exam. The answer required was, of course, "Take a bearing, sir". So, even if you haven't got a compass, you can still take a RELATIVE bearing.
Logged
Retired, UK foreign going Masters Ticket.

kuusuru

  • Forum member
  • Posts: 83
Re: Accuracy of geographical coordinates
« Reply #9 on: March 03, 2009, 23:55:55 »

To kuusuru's point,
On a real ship in real sea conditions having a compass is VITAL. When I was taking my oral exams for my tickets, one of the favourite questions was:- "If you see a single white light at night what do you do?" I was asked that same question for 2nd mates exam, for mates exam and for masters exam. The answer required was, of course, "Take a bearing, sir". So, even if you haven't got a compass, you can still take a RELATIVE bearing.

So combining this with Terry's reply above... you take a bearing on your white light, then a few minutes later you take another bearing, and if they are the same, you know you're on a collision course?

Sorry for asking what might be obvious questions :sleepy: I have plenty of experience with map and compass, but only for land navigation, and we only took bearings to stationary objects like trig points.
Logged

Fernando_Pastor

  • Forum member
  • Posts: 9
Re: Accuracy of geographical coordinates
« Reply #10 on: March 04, 2009, 00:18:07 »

To add to that, If you observe a vessel over a period of time and its relative bearing does not change, then either you are both stationary, or you're going to collide. No compass required.

You are right but you have to stay all the time on the same position. It could be even half an hour. If you have a hand bearing compass you can go from port side to starboard side or from bow to stern and check the bearing to the other vessel every 2 minutes, for example. Meanwhile you can do a lot of things on board. More fun  :thumbs:.

Fernando
Logged

mvsmith

  • Guest
Re: Accuracy of geographical coordinates
« Reply #11 on: March 04, 2009, 00:51:14 »

Hi kuusuru,

That's right, a constant relative bearing is a good warning that you are on a collision course. This has only limited application in land navigation—don't try it with automobile headlights!

Regards,
Marty
Logged

mvsmith

  • Guest
Re: Accuracy of geographical coordinates
« Reply #12 on: March 04, 2009, 01:05:09 »

You are right but you have to stay all the time on the same position...
Fernando

If you use camera 3 with binoculars to track the ship, you can switch back to camera 2 or 1 without disturbing camera 3.

I suggest that you spend some time exploring what can actually be accomplished in the simulator before making requests that would be costly to implement at this stage.

The charts are not in a form that makes printing them feasible. The harbors in SS are real places; real nautical charts are available.
Logged

Fernando_Pastor

  • Forum member
  • Posts: 9
Re: Accuracy of geographical coordinates
« Reply #13 on: March 04, 2009, 10:49:21 »

If you use camera 3 with binoculars to track the ship, you can switch back to camera 2 or 1 without disturbing camera 3.

Ok, but what happens if you have to check 2 o 3 vessels overtaken your ship from abeam and both sides in a big ship, for example Veermas? The helmsman camera cannot track them because only see in front of him and the other camera is blocked in one side because in many cases he cannot see the entire horizon. You are dancing with the drama.

Quote
making requests that would be costly to implement at this stage.

Maybe, I don’t know but I think there is code for that developed already probably is not so costly. I only ask for a thing that improves the game for the people who like navigation as much as the ships. Compass it’s a tool that if you have it you use it, and the players can learn a lot of concepts used on real navigation with it.

Quote
The charts are not in a form that makes printing them feasible. The harbors in SS are real places; real nautical charts are available.

I’ve got nautical charts (paper and vector) and I cannot use them, believe me. That's my request from the begining.

Regards
Fernando

 
« Last Edit: March 04, 2009, 11:47:23 by Fernando_Pastor »
Logged

Traddles

  • Global Moderator
  • Posts: 5934
Re: Accuracy of geographical coordinates
« Reply #14 on: March 04, 2009, 12:17:34 »

Hi kuusuru,
To answer your question above, if the bearing remains constant then there is a definite risk of collision. You can see the same effect from a car approaching a cross roads. If the car on the other road shows in the corner of your eye at the same angle to you constantly, then watch out. :o This is of course not recommended, but merely an example for you. The same effect can be seen with a pedestrian crossing the road ahead of your car. If he is on your left side and APPEARS to be moving to the right he will pass clear ahead of you, if he appears to be moving to the left, he will cross behind you, but if he appears to be not moving you might end up with a big dent in your car and a court case. :'(
Logged
Retired, UK foreign going Masters Ticket.

kuusuru

  • Forum member
  • Posts: 83
Re: Accuracy of geographical coordinates
« Reply #15 on: March 04, 2009, 13:10:25 »

Hi kuusuru,
To answer your question above, if the bearing remains constant then there is a definite risk of collision. You can see the same effect from a car approaching a cross roads. If the car on the other road shows in the corner of your eye at the same angle to you constantly, then watch out. :o This is of course not recommended, but merely an example for you. The same effect can be seen with a pedestrian crossing the road ahead of your car. If he is on your left side and APPEARS to be moving to the right he will pass clear ahead of you, if he appears to be moving to the left, he will cross behind you, but if he appears to be not moving you might end up with a big dent in your car and a court case. :'(

Thanks mate.  I try to estimate from the map and the vessel's heading if we are on a collision course, but I seem to stuff it up an awful lot, and find myself having to make sudden and drastic turns which are not always successful (or, if you evade the first vessel, put you in the path of something else).  In the absence of a compass, I like your suggestion above to line up through the bridge, I'll give that a go  :thumbs:
Logged

mvsmith

  • Guest
Re: Accuracy of geographical coordinates
« Reply #16 on: March 04, 2009, 16:00:47 »

Hi Fernando,

A version of Ship Simulator that comes closer to meeting your requirements will soon be available from http://www.vstep.nl/

If you visit that site, and click on Products > Ship Simulator Professional, you can get the details and ordering information for that program. It provides the compass that you want—although the reading is True Bearing rather than Magnetic.

I think you will agree that it is a more suitable product for a serious, experienced mariner such as yourself.

Regards,
Marty

I might add that your hypothetical scenarios that require tracking multiple targets or piloting via bearings on objects ashore are unlikely to occur in this entertainment version of the simulator. That amount of AI traffic and variety of courses they might follow cannot be supported in practical missions.
Some time spent with the mission editor will show what can reasonably be expected in scenarios.
« Last Edit: March 04, 2009, 16:23:29 by mvsmith »
Logged

Fernando_Pastor

  • Forum member
  • Posts: 9
Re: Accuracy of geographical coordinates
« Reply #17 on: March 04, 2009, 16:47:37 »

Hi mvsmith

I just want to be positive. I like the game; I think it’s a great game without a compass, but it will be greater with it. That’s all. Peace  8)

Regards
Fernando
Logged

TerryRussell

  • Guest
Re: Accuracy of geographical coordinates
« Reply #18 on: March 04, 2009, 18:35:15 »

Thanks mate.  I try to estimate from the map and the vessel's heading if we are on a collision course, but I seem to stuff it up an awful lot, and find myself having to make sudden and drastic turns which are not always successful (or, if you evade the first vessel, put you in the path of something else).  In the absence of a compass, I like your suggestion above to line up through the bridge, I'll give that a go  :thumbs:

I kep a couple of fairly fast vessels at Chichester Harbour. My favourite is the Sunseeker Monterey, which is about 32 foot long (waterline is 27 ft). That goes along at about 45 kts quite comfortably. It can go faster, perhaps 52 kts. Now, when I'm going from Chichester, up past the forts and along towards the western end of the Solent, there is a lot of traffic in pretty much every direction. As I cruise along, I keep a mental note of where each of the possibly conflicting vessels is aligned. So that tanker on my port side is currently alinged with the windcreen widper motor. The Ferry on the Starboard side is aligned with the top left of the side panel. And so on.

If those alignments don't change substantially within a few minutes, I''ll take avoiding action, per COLREGS.

I do carry a prismatic, damped sighting compass, especially designed for use on a fast boat, but I only use it for practice, triangulating against a printed map. It's good practice in case the sat nav (GPS) ever packs up and the back up also fails. But I've never had to use it for real. That just isn't the way it works, unless you're out in some antique sailing boat, making 4 kts with a good wind behind you.
Logged

Fernando_Pastor

  • Forum member
  • Posts: 9
Re: Accuracy of geographical coordinates
« Reply #19 on: March 04, 2009, 21:27:21 »

Hi Terry,

I don’t know how is in Britain I believe that is the same than in Spain, but here you can navigate without GPS (1 or 13), ECDIS, radar, radar with ARPA, Sounder meter, an oboe and sun glasses if you want, but you cannot get underway without a simple hand compass and a paper chart of your navigation’s zone. If you have an accident and you don’t have them on board you are in big troubles. Why? Because authorities are wiser than we are and they says so.

I use to go from Valencia to Ibiza/Formentera/Mallorca sailing every year and I use the compass often and never have I used a GPS because is useless for me. When sailing abroad is the same but multiplied.

Regards
Fernando
« Last Edit: March 04, 2009, 21:30:36 by Fernando_Pastor »
Logged

TerryRussell

  • Guest
Re: Accuracy of geographical coordinates
« Reply #20 on: March 04, 2009, 21:31:16 »

Below about 45 feet there is no such legislation in the UK. Any fool can jump in a vessel and career off to their doom without breaking the law. I thought that was the same throughout the EU. I'd be very pleased if it isn't.

Unless they speed in a harbour, or they're drunk or cause an acident when other laws start to come into operation. But you have to be pretty determined to do this. You should have lifejackets, flares, and so on. You should have a radio, at least. But there's no real laws to compel you to do so. Shame...
« Last Edit: March 04, 2009, 21:34:48 by TerryRussell »
Logged

Fernando_Pastor

  • Forum member
  • Posts: 9
Re: Accuracy of geographical coordinates
« Reply #21 on: March 05, 2009, 11:27:31 »

In Spain there are a lot of regulations for sailing. You have to pass exams even if you steer a small 24’ feet vessel with a 5CV engine near the shore. I quite sure that in Italy, France, Greece, Uruguay and Argentina is the same, and probably Belgium and Holland. But local authorities some of them (Spain and Greece) are lees exigent with foreigners than with their own sailors and local boat owners.

It's good and bad, it depends.
Logged

TerryRussell

  • Guest
Re: Accuracy of geographical coordinates
« Reply #22 on: March 05, 2009, 19:40:59 »

I've got mixed emotions about it. On the one hand, it's a long tradition that access to the sea is unrestricted. That means that anyone should be able to navigate the seas of the UK without retriction.

But, on the other hand, having been at the helm of an Arun Class 42 foot Lifeboat from time to time for some years until I became too old (and for some years after that), I have seen the consequences of untrained and unqualified people being let loose on the sea.

Pulling bodies from the water is one of life's less jolly experiences. Pulling children's lifeless bodies from the sea as a result of the stupidity of their parents has been heartbreaking.

So all in all, I back tighter legislation, even if some of life's freedoms are eroded.
Logged
Pages: [1]   Go Up
 
 


SMF 2.0.14 | SMF © 2017, Simple Machines