Black Hole in TTN5

DerekG · Occasional Visitor Joined: Nov 08, 2003 Posts: 30

When planning an "A+B" route, I sometimes experience a "no route found" message from my TTN 5.1 and wondered if anyone has some suggestions on what might be causing them?

Believe it (or not) if I try to map a route from Harwich International Ferry Terminal (Parkeston) to Manchester or Liverpool I get this "no route found" message, but if I choose Birmingham for the destination, I get a route to follow! It is almost as if there is a boundary line from the River Stour to the River Mersey and any destination north of this line is in a Black Hole. The inability for TTN to find a route is influenced dramatically by whether I choose the fastest or shortest route between A and B, and also whether the starting point is close to the river Stour's estuary to the North of Harwich town. On the shortest route, if you start too close to the estuary, then the route starts from the other side of the river half a mile away - even though there is no official ferry crossing to cover this half a mile! If you gradually adjust the starting position away from the river (i.e. move South) then you hit the point where "no route found" appears.

After a 14 hour ferry crossing back to the UK, I find having no route or a totally wrong route to follow quite exasperating. I set off following the general road signs and, all of a sudden, after nearly a mile of heading West, TTN kicks in and starts trying to get me back on track. It's clearly trying to get me North of the river as quick as possible and has me going down almost every cart track and "C" road in the South Ipswich area. I might add that going in the other direction from the North West of England to the ferry port is an absolute dream, fastest or shortest, I arrive at the port gates by the most humane routing possible.

I f you want to try out what I am explaining for yourself then here is a guaranteed scenario. First ensure POI names are turned on and you are doing an A+B routing.

Point A - Harwich Town Station. You will need to zoom in tightly to have the station name appear as a dot to the right of where the railway line finishes in the centre of Harwich. Tapping the dot causes the adjacent street address "5, 22 Geroge Street" to sppear, which is perfectly acceptable. The further North West you go up George Street for a starting point, the greater the chance of the route starting from the other side of the River Stour.

Point B - M6 junction 17 (Sandbach in Cheshire). You can choose the actual motorway junction, but exactly one and a half miles due East along the A534 is a transition point where, any further East you will get the "no route found" message. Congleton is a full 5-6 miles east of the M6 J17 and guaranteed to give this message, especially if point A is no further north than "5, 22 Geroge Street".

Choose the Shortest route for maximum effect in getting a "no route found" warning. Fastest route often overcomes this warning message - but not always!

I fully appreciate that this problem could well be unique to me and no other TTN 5.1 customer is able to replicate it. If so, then I can work on that and experiment with the PDA's memory consumption, but it would be helpful to know I am the only one. A hard reset is a very big step to take, especially if there's nothing wrong with your PDA and the software has a potential bug. Sorry the posting is rather long, but I appreciate any help you can give me.

Oldboy · Posted: Wed Oct 19, 2005 10:27 pm Post subject:

The symptoms that you describe is normally attributed to being short of memory.

To set a route TT keeps a record of all the roads and turns that need to be made. If you the 'shortest route' there will be very many more of these.

From Harwich Town Station to Congleton the GO that I used, looked at 600,000 roads. The Route Text was so long I gave up.

Have you tried a similar exercise on another long route, say from Cornwall to Scotland?

Incidentally I couldn't reproduce going across the estuary.
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R1chard · Regular Visitor Joined: Feb 07, 2004 Posts: 64

I just tried what you suggested and I replicated it on my HP2110 but I can't suggest a reason why. Perhaps you should take it up with TomTom.

Richard

DerekG · Occasional Visitor Joined: Nov 08, 2003 Posts: 30

OldBoy,

I notice you are using TTGO which is why you might not be able to replicate the problem? I take your point, however, about trying to find another pair of journey points, but it seems to me to be just like looking for a needle in a haystack? I did try Harwich to Lands End in Cornwall and all went well, as did Harwich to Birmingham. It has taken me several months to realise that the problem has not been a slow startup time for my GPS or the road structure inside the ferry port itself which more resembles a double-pretzel knot with no clear way out.

Richard,

This is astounding news that the problem is repeatable. Would you kindly let me know the amount of free memory you have, but so we get a level playing field, can you first switch off any bluetooth and WiFi and also remove any SD and CF memory cards from their slots. Under these conditions on my hp2210 and immediately following a soft reset I have a total of 26.25MB free, but does anyone have a view on the acceptability of this figure for running TTN 5.1 on a PDA?

Thanks to you both for trying the A+B planning for me.

DerekG · Occasional Visitor Joined: Nov 08, 2003 Posts: 30

I feel I should be putting more effort in, so I've tried the most ridiculous A+B route planning I could think of and TTN still fails "No route found" on a shortest route request. The route was from Harwich Town Station to any B-road in Felixstowe the other side of the River Stour in a North-Easterly direction.

If I keep the start point and move the destination due west along the north bank of the River Stour, it is not until I get through the village of Brantham, that a shortest route is successfully planned.

I think TomTom really need to be involved on this one, but I'll first see what response I get from checking the available PDA memory.

LiveLifeGoJump · Posted: Thu Oct 20, 2005 3:03 am Post subject:

I have planned a route from the north east to north whales using the shortest & it looked at over 1 million (if I remember correctly) but today I planned a route (quickest) from Edinburgh to the north east via Jedburgh & it came up 'no route found'.

Mio 168 & TTN5. Don't think it could by memory problem if NE to Wales worked ok.

According the the TTN5 the road floats in Catcleugh Reservoir approx 15 mtrs from the east bank Laughing

It also thinks that using the A1 western bypass (passed the Metro Centre, Gateshead) is the quickest way. Even the M25 traffic moves faster Laughing

.
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Pocketgps · Posted: Thu Oct 20, 2005 3:24 am Post subject:

I have just tried the A+B route feature several times, same route as you chose, and also from Poole passenger terminal to Glasgow and several other very long routes and all work fine using fastest or shortest route.

Tried this on both a Medion 95000 and a Mio168, going to the TT5 version screen showed that one had 16.7MB of Free ram and the other 16.5MB.

gacrane · Regular Visitor Joined: Jul 26, 2004 Posts: 65

After playing all lunchtime I have established that I get exactly the same response from TT as first described by DerekG

It will sometimes give me an "Approximate Route Found" which has taken me over the river as the start point if I move the start point I place North up the road.

I run TT Version 5.1 on my iPAQ 2210 I had 19.5mb free RAM according to the TT Show Version screen. Just for information I can do I Shortest route from Plymouth to Inverness without any issues, it is slow though it did analyse over 2,000,000 roads

Very odd Question

jguiver · Posted: Thu Oct 20, 2005 2:19 pm Post subject:

OK, lets go for the big one.

Mio 168, TT5.1, 1GB SD Card, 24.45MB free storage memory, 24.52 free program memory, no POI's, no C Roads.

John O'Groats to Landsend, Shortest Route:
'No Route Found' about 3/4 of the way through the process, 3million + roads analysed.

Harwich International Ferry Terminal (Parkeston) to Liverpool, Shortest Route:
Completed successfully. Roads analysed, 1.4 million

Must be a memory issue?

Pocketgps · Posted: Thu Oct 20, 2005 6:29 pm Post subject:

R1chard · Regular Visitor Joined: Feb 07, 2004 Posts: 64

DerekG · Occasional Visitor Joined: Nov 08, 2003 Posts: 30

Richard,

Thanks for coming back to the forum. It would appear that there are numerous blind-spots across the UK, particularly when using the shortest route and even more likely when routing Northwards.

A further point I have discovered is that the Great_Britain_Plus map does not contain the same level of British Isle detail as the Great_Britain map. Clearly there has to be some compromises for the ability to have all of Europe's major roads available, but (until today) I had always thought that the two GB versions were identical - apart from the addition of the major roads outside of the UK. If the "plus" version has fewer side streets to pick from, it might explain why some members posting to this thread do not experience the same level of mis-routing? I can definitely prove that when using the normal GB map for navigating the shortest route, TTN5 will not route the 10 miles across the River Humber from just north of Grimsby to the river-side streets in Hull. I switch to the GB "plus" map and the shortest route works every time - primarily because the streets I used for routing between are not being shown and I have to pick a more favourable start and end point!

I think as TTN customers we have a right to be able to map the fastest route from (say) Lands End to John-O-Groats, but considering the number of alternatives, we should expect the odd hiccup for a shortest route over the same journey. However, a more graceful failure, like "too many alternatives" would be preferable to the misleading "no route found" warning. No Route Found should mean exactly what it says, and not become a pseudonym for "TomTom's got a headache from working out your shortest route"!

Ideally, TTN should anticipate the overload situation, advise you of the limitation and automatically fall back to the less dense street granularity to achieve the routing. Carrying both map versions around is cumbersome, but maybe that is what is needed to get the best use out of my investment? If TTN tells me the fastest route from Harwich to Manchester is via the M25 and up the M1, it can't possibly know it's a wet Friday afternoon. I therefore need all the alternative routing options - including the shortest - to decide a more workable route home. If that means switching maps, then so be it, but at least I now know I have to do just that.

hgm · Occasional Visitor Joined: Oct 25, 2005 Posts: 50

I thought I would try out the Land's End to John O'Groats on my iPaq 3715. To my suprise after reading the above posts, it worked!. Gave an answer of 19:47hrs - 811 miles including use of a toll road.

Henry

R1chard · Regular Visitor Joined: Feb 07, 2004 Posts: 64

Derek

Hmm. Not convinced about the differences between GB and GB plus maps. I just retested the Harwich routes using the GB Map and found exactly the same issues as I did with the GB plus map.

Also I think the jumping to the north side of the river is caused by TomTom assuming that the three ferry routes as roads as they appear to pass very close to land.

I think you should take this up with TomTom and see what they say.

I also had a look at the streets of Hull and couldn't see any difference between the maps.

There shouldn't need to be any compromise because the GB plus maps are significantly bigger than the GB maps.

Richard

hgm · Occasional Visitor Joined: Oct 25, 2005 Posts: 50

I've now tried the Harwich to Congleton. That comes up with No Route Found for both shortest and fastest. That can't be a lack of memory when the Land's End to John O'Groats works. (V5.1, GB map)

Henry

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