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And yet I have no need whatsoever for ETA, Distance remaining is useful and Speed is essential bearing in mind the inaccuracy of vehicles speedos and the proliferation of speed cameras (in the UK) nowadays.
I agree with Alan (Alan_sh), give us a bigger speed indication!
Or, why not give us a choice of which indication we would like to be seen in a larger format, keeps everyone happy.
And yet I have no need whatsoever for ETA, Distance remaining is useful and Speed is essential bearing in mind the inaccuracy of vehicles speedos and the proliferation of speed cameras (in the UK) nowadays.
I agree with Alan (Alan_sh), give us a bigger speed indication!
Or, why not give us a choice of which indication we would like to be seen in a larger format, keeps everyone happy.
Bob
I must take you to task over the inaccuracy of vehicle speedos. They are actually very accurate devices but with a known and repeatable error.
For example if your speedo has an error of +10% at 70mph then when it reads 77mph you know you are doing 70mph. It will give you this value repeatedly and with great accuracy given the known error.
Now the GPS speed is something entirely different. It relies on a good satellite lock and driving at a constant speed in a straight line to give you an accurate reading. Accelerating, decelerating, driving round a corner, high buildings, tree lined roads and many other variables will considerably affect the indicated speed.
When your driving licence depends on it I know which one I will always use.
I would have gone even further than linknet. As said, GPS indication of speed is of variable accuracy, and sometimes several seconds out of date, so only a fool would rely on that information.
As for car speedos, yes they are allowed a leeway, but only in one direction - they are not allowed to show even half a mile per hour less than your true speed, so they are hardly likely to get you into trouble (unlike the SatNav one which has no such requirement).
By no stretch of the imagination can speed indication on a sat nav be considered essential, it might under certain circumstances, and for some features be useful, but no more.
I am sorry to say, that if truly accurate speed indication is required, the only current solitution is a properly and regularly callibrated speedometer (often an additional unit).
I checked a route from London to Radlett on the TomTom 510 and it included directing me down a one way street the wrong way. It's been one way for over 10 years.
Going on to the TeleAtlas site I checked a few regularly used Z roads in Cornwall in an area I know. In the area I checked TeleAtlas does not seem to distinguish AT ALL between roads that can take two way traffic, single track with passing places, and overgrown bridle paths and tracks that haven't seen a car in 30 years.
It seems incredible that when we have had 1:50000 OS maps showing most of this information for years the map companies don't seem to be interested in using any of it. Maybe it's all down to cost.
My opinion after much usage of Tomtom navigating is that TT5 works just fine. It will get one from A to B and that is far more important than having the speed showing on the PDA.
If Tomtom add more bits and pieces to TT6 they may very well take bits and pieces away. Imagine TT6 adding the speed option but removing ‘Postcodes’ or ‘Advanced Planning.’
No, the programme is great, its only weak link is up-to-date and accurate maps. However, whatever GPS programme one uses up-to-date and accurate maps is on a par with chasing the Holy Grail. _________________ Tomtom Go 720.
Navcore 9.510
Central and Western Europe v855.2884
GPS World Traffic cameras
Home 2.7
iPhone 3G
My opinion after much usage of Tomtom navigating is that TT5 works just fine. It will get one from A to B and that is far more important than having the speed showing on the PDA...
While I agree with most of your comments, having seen several different SatNav systems, I do not share your opinion about TT5 being just fine.
While I would not go so far as to slag it off, there are areas where there is much room for improvement. Route planning (as opposed to route calculation) and POI handling are just two areas where I feel that TomTom is deficient.
This is in no way suggesting that they are not better in these areas than much of the competition, just that there is room for considerable improvement rather than just minor tweaking.
Another area sadly missing in many systems is a simple way to avoid a particular location. The nearest most systems get to that is allowing you to use waypoints (or whatever name they use) which should (hopefully) keep you away from where you want to avoid. For many commercial drivers, this is a requirement and being able to feed in a database of 'avoid' locations could be the next killer feature.
Good God Man! You actually have a speedometer?! You must be driving one of these new cars with doors and windows! Does it have an engine as well? Damn your lucky!
Yep, and it even has a muffler, which quietens the put, put, put so it doesn't scare the farm animals. And fancy turn-signals, to show which way yer fixin' ta go.
But ya, seems sensible to make a setting to enable/disable speed (for those content with its delayed response) and altitude.
I agree that these new features sound like marketing, just as it essentially is with M$'s Vista.
Hi neil01
When it comes to route planning (other than a straight A to B) I use the Itinerary Planning option. For instance, on one journey in France I had up to 12 Waypoints to take me along certain routes/avoid towns etc and it all worked like a dream.
I agree that your idea of a database of 'avoid locations’ would be a step in the right direction but I cant see Tomtom going along that path. We will wait and see. _________________ Tomtom Go 720.
Navcore 9.510
Central and Western Europe v855.2884
GPS World Traffic cameras
Home 2.7
iPhone 3G
I am sure they can add some sort of info collection to TomTom so that if the vehicle is moving at an average speed significantly slower than the roads speed limit then this info can be sent up the gprs call back to their servers, then if enough reports come in for that area, then boom, update the data so that tomtom receives a traffic update. Could that work?
So does know one have any comments about my solution to the poor TMC data available in the UK?
I must take you to task over the inaccuracy of vehicle speedos. They are actually very accurate devices but with a known and repeatable error.
For example if your speedo has an error of +10% at 70mph then when it reads 77mph you know you are doing 70mph. It will give you this value repeatedly and with great accuracy given the known error.
Now the GPS speed is something entirely different. It relies on a good satellite lock and driving at a constant speed in a straight line to give you an accurate reading. Accelerating, decelerating, driving round a corner, high buildings, tree lined roads and many other variables will considerably affect the indicated speed.
When your driving licence depends on it I know which one I will always use.
Regards
Roger
Not suprisingly, I don't agree.
In my last car and on my last motorbike the speedo was a fixed percentage out across the range from 30mph upwards. However, on my recent car the speedo is only 1 or 2 mph right up to about 50 mph when the readout error starts to increase at a rate that is not a percentage.
I do realise that driving on twisty roads and going up and down hills does affect the accuracy of the satnav readout but only if you are driving on roads that are extremely hilly and bendy. Going up gentle inclines and round gentle bends presents little error in the readout.
Obviously you have to have a good fix before you get an accurate readout, if your signal strength is good and you have a acquired a reasonable number of satellites, and providing your position isn't jumping around erratically the probabilty is that the indication is accurate.
Of course I don't rely entirely on the speed readout of the satnav I use it in conjunction with the speedo of the vehicle I am driving at the time. Firstly, it allows me to find out the error in the speedo and thereafter can be used as a reminder.
In my last car and on my last motorbike the speedo was a fixed percentage out across the range from 30mph upwards. However, on my recent car the speedo is only 1 or 2 mph right up to about 50 mph when the readout error starts to increase at a rate that is not a percentage.
I didn't state that it was a fixed percentage, I said that it was a known error, and only gave a percentage error as an example at a particular speed.
The error will be known by the manufacturers and to get that information for yourself may require calibration by some method.
Of course I don't rely entirely on the speed readout of the satnav I use it in conjunction with the speedo of the vehicle I am driving at the time. Firstly, it allows me to find out the error in the speedo and thereafter can be used as a reminder.
One further thought, you are using the GPS speed to calibrate the speedometer. That's fine, but first you need to calibrate the GPS speed against a known standard otherwise you are just calibrating one device with another of equally unknown accuracy. After all the GPS speed is an averaging calculation designed by TomTom and I know just how much I trust their software
Just because it seems about right doesn't mean that it is accurate.
Speedometer accuracy is very dependent on the wheels and tyres you are using.
Manufacturers would typically set the speedo to a slight over read to accommodate the largest diameter tyres (and largest wheel) you would expect on a model.
The wide range in variations of experience is usually due to a closer match between the expected wheel/tyre diameter and what you are actually driving.
Lower profile tyres and smaller wheels would typically give a more exaggerated reading.
There is no EC directive or special speed reduction plan behind this.
The responsibility for the speedo to be accurate - along with anything else on your car, is actually yours.
The manufacturers try to avoid any possible contingent liability. After all, who would you rather sue, Mr John Smith or Ford?
As it isn't practical (at reasonable cost) to make speedo's exact; manufacturers make it as accurate as they can or overstate the speed (as few people are fined or have accidents going to slow).
When you last had new wheels or tyres, did anyone calibrate your speedo?
Thought not.
When you last had new wheels or tyres, did anyone calibrate your speedo?
Thought not.
No, but I carried on using the same satnav, and later on a newer one, on both my cars and motorbike, in fact the motorbike had several changes of tyre a year, in each case there was no noticeable difference in the error noted between the satnav and the speedo.
One further thought, you are using the GPS speed to calibrate the speedometer. That's fine, but first you need to calibrate the GPS speed against a known standard otherwise you are just calibrating one device with another of equally unknown accuracy. After all the GPS speed is an averaging calculation designed by TomTom and I know just how much I trust their software
Just because it seems about right doesn't mean that it is accurate.
Regards
Roger
Agreed.
However, I have worked with, and on Satnav since it first became commercially available. The first one I saw, in fact helped install on a ship, ran on a Wang computer and output it's data to a printer. It filled a case the size of a large filing cabinet and it's antenna had a radius of nearly 1 metre 8O
At the time we thought it's accuracy to within a mile or so was brilliant, until we approached the coast of Australia and it put us 2 miles inland 8O we then checked the chart and this particular coastline was last charted by Captain Cook!
So with the errors of charting in those days together with the accuracy of the satnav, it wasn't too bad!
Although I haven't personally checked the calibration of the satnav with calibrated instruments, I have had the opportunity to compare it against another PDA based software/hardware and a couple of Garmins and they are all reading the same. Based on my experience over the years and my simple comparisons I have enough faith that the readout is accurate enough for what I want
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