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symbian Occasional Visitor
Joined: Jun 27, 2008 Posts: 3
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Posted: Fri Jun 27, 2008 10:20 am Post subject: Racing with VMG |
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Im looking for an app for a Symbian phone (Nokia 6110 Navigator) that uses the built in GPS to navigate some way points. There are 100s of java apps that do this but Im looking for one that will help with short course sailing races.
I would like to enter say 5 way points on a practise lap (the marks move between races) then during the race have the GPS display my current speed and VMG to the next mark. Once I round that mark the app should alter the display for the next mark. There is no need for any map overlays here.
Does anything like this exist? Any help would be greatly appreciated.
Thanks
http://en.wikipedia.org/wiki/Points_of_sail
Wikipedia wrote: | No-Go Zone.....
Pointing ability is very important for racing sailboats as the real goal in a race is almost always velocity made good (VMG). VMG is the speed at which the boat is approaching the destination (usually a buoy or mark) as opposed to the speed at which the boat is moving through the water (boat speed). These two speeds almost always vary because, during a race, a boat usually cannot sail directly to the next mark. VMG may also refer to the upwind vector of boat speed (this is often the VMG expressed on sailing instruments). |
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symbian Occasional Visitor
Joined: Jun 27, 2008 Posts: 3
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Posted: Fri Jul 04, 2008 10:18 am Post subject: |
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Can anyone suggest somewhere I may get a better response?
Ta |
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philpugh Lifetime Member
Joined: Dec 28, 2005 Posts: 2003 Location: Antrobus, Cheshire
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Posted: Fri Jul 04, 2008 6:00 pm Post subject: |
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Not seen anything specifically for Symbian phones.
But...
Most simple hand-held GPS units will probably do what you want.
In navigation mode they will show bearing to next way point, distance to go and velocity (which in the case of navigating at sea will be "velocity over ground" - which I guess is what you are after?
I would recommend a handheld GPS for this because:-
battery life - you will get 24hrs+ on two AA cells with most simple GPS units (eg GARMIN Geko)
they are weatherproof - I have a 6110 and I certainly wouldn't take it to sea in racing conditions (it's going sailing off west coast of Scotland later this month but it will probably only be used ashore). You could use a box/bag etc to protect - but it makes it very difficult to handle. Some GPS units will actually float if dropped overboard.
ease of use - the 6110 will be trickier to use (menu navigation / waypoint entry etc) due to the nature of these things. A dedicated GPS unit has been designed to be usd 'in the field' (or on the water !)
If you are going to do this regularly then it would be a smart thing to invest in a handheld. Have a look on ebay - you can pick up some bargains. _________________ Phil |
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symbian Occasional Visitor
Joined: Jun 27, 2008 Posts: 3
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Posted: Mon Jul 07, 2008 9:59 am Post subject: |
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philpugh wrote: | Not seen anything specifically for Symbian phones.
But...
Most simple hand-held GPS units will probably do what you want.
In navigation mode they will show bearing to next way point, distance to go and velocity (which in the case of navigating at sea will be "velocity over ground" - which I guess is what you are after?
I would recommend a handheld GPS for this because:-
battery life - you will get 24hrs+ on two AA cells with most simple GPS units (eg GARMIN Geko)
they are weatherproof - I have a 6110 and I certainly wouldn't take it to sea in racing conditions (it's going sailing off west coast of Scotland later this month but it will probably only be used ashore). You could use a box/bag etc to protect - but it makes it very difficult to handle. Some GPS units will actually float if dropped overboard.
ease of use - the 6110 will be trickier to use (menu navigation / waypoint entry etc) due to the nature of these things. A dedicated GPS unit has been designed to be usd 'in the field' (or on the water !)
If you are going to do this regularly then it would be a smart thing to invest in a handheld. Have a look on ebay - you can pick up some bargains. |
All good points. I am looking at hand-helds just now. The method most hand-held GPSs calculate VMG is VMG to a specific mark but its actually much more helpful having a VMG along a specific heading that will not change as you approach a mark.
Thanks for your help |
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philpugh Lifetime Member
Joined: Dec 28, 2005 Posts: 2003 Location: Antrobus, Cheshire
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Posted: Tue Jul 08, 2008 5:45 pm Post subject: |
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VMG refers to actual velocity with respect to a fixed point - in the case of a GPS this is usually the next waypoint.
For velocity along a bearing... Some GPS units allow you to project a waypoint (i.e. distance and bearing from current position) - you could then use this waypoint to acheive what you want. Have a look at the specs/manual (online) of the Garmin GPS72 - an entry-level marine GPS - that can be got quite reasonably from ebay and other outlets.
I suspect any of the marine biased units allow you to see VMG with respect to the next waypoint in a route. So for a race you would enter the waypoints you want, create a route using these and during the race 'follow' the route. The unit should then be able to display bearing to next waypoint, VMG to the waypoint, distance etc.
www.garmin.co.uk should lead you to all the info you need. _________________ Phil |
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