Navionics iPhone plotter

[Fergus]

It seemsto give a very accurate position but is hopeless on speed. Any ideas please?

 

[Cappen Boidseye]

What are you comparing it to? I thought GPS based speed calculations were far more accurate than car speedometers or boat based logs.
I use a charting app, (from flytomap.com) It works really well and gives a very accurate course over ground, of course that is different from speed through the water, because the water won't stay still!

 

[bignick]

I tend to find that it does the same whether its on Navionics, Multimap or anything else, which makes me think its the resolution of the phone's GPS, not the software.
Only thing I can suggest is to use an external GPS unit through bluetooth, which will feed the phone more accurate position info.

 

[FWB]

Speed is accurately displayed when using the TomTom app or the CamerAlert app. Like you I find the speed to be of little use with Navionics. Presumably it is because the speed is so low. Interesting to see if the suggestion of an external gps would cure this.

 

[Cappen Boidseye]

My marine app shows an accurate speed to a resolution of 0.1 knots. The other (street based) apps don't do a finer resolution than 1 mph, so at very low (drifting with the tide) type speeds, they will often give a speed of 0 with the odd spike of a few mph.

I have mentioned the proper name of my marine app (Iphone only, maybe Ipad as well) on other threads, I just searched for UK marine navigation through Itunes to find it. Sorry I don't have my phone with me at the moment or I would give you the proper name.

My charty App on the Iphone is WaterMap, from Flytomap.

 

[bignick]

Yes, the speed from the phone seems accurate when using CoPilot, I think it is more accurate than the speedometer in the car, but at low speeds it drifts all over. It will 'display' to 0.1kt, but if you watch it on the boat ow while walking it will say not moving for a while then increase to 8-10kts, then slow right down again. Not much use if you ask me...
Am seriously considering the Digital Yacht kit to send the GPS info to the phone, and if it works ok I'll treat myself to an iPad for Christmas...

 

[xyachtdave]

It seemsto give a very accurate position but is hopeless on speed. Any ideas please?

Hmmmn not sure I would agree with that statement!

I am not a chart plotter person, but have hand held Garmin etc for use when out of home waters. On a trip to Ramsgate recently a friend bought an ipad with the latest Navionics app along and I must say I was quite impressed with it to the point I wanted one.

I have had the Navionics app on my iphone 3GS and not really used it at all until the return journey. It gave our position as error 4.5 miles to the south. I switched off and on again and it put us slightly nearer to our position, in the sea this time though as opposed to in Margate High Street.

I checked our position several times and eventually when further inshore (where the phone would work) it gave an accurate position verified by visual on a buoy.

The guy in the i shop told me the ipad/phone used assisted gps signals, as in helped from the phone network. Also when at home the position is 250m off easily, I put this down to google overlay not being as accurate as Navionics, now though I am not so sure.


Edit Was thinking digital yachts AIS thing that wirelessly sends your input, GPS etc to your device would be a good way of getting proper info into the user friendly ipad etc

 

[Cappen Boidseye]

Hmmmn not sure I would agree with that statement!

I am not a chart plotter person, but have hand held Garmin etc for use when out of home waters. On a trip to Ramsgate recently a friend bought an ipad with the latest Navionics app along and I must say I was quite impressed with it to the point I wanted one.

I have had the Navionics app on my iphone 3GS and not really used it at all until the return journey. It gave our position as error 4.5 miles to the south. I switched off and on again and it put us slightly nearer to our position, in the sea this time though as opposed to in Margate High Street.

I checked our position several times and eventually when further inshore (where the phone would work) it gave an accurate position verified by visual on a buoy.

The guy in the i shop told me the ipad/phone used assisted gps signals, as in helped from the phone network. Also when at home the position is 250m off easily, I put this down to google overlay not being as accurate as Navionics, now though I am not so sure.


Edit Was thinking digital yachts AIS thing that wirelessly sends your input, GPS etc to your device would be a good way of getting proper info into the user friendly ipad etc

I don't know how the different systems work on the different Iphones and Ipads, I have an Iphone 4 and it's positioning so far has been spot on, my only gripe is that I often get the compass interference warning, depending on the App in use(Thankfully not with Watermap), very annoying as I don't want to use the compass most of the time.