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Posted: Mon Nov 05, 2007 9:30 pm Post subject: Newbie Question: Routing Algorithims
Hi,
Another newbie question. I assume that the Routing Algorithims are part of the GPS, not the mappling library. Assuming that this is correct, is there a big difference in the quality of the routing that one GPS provides over another?
If so, who has the better reputation and who is less reliable?
Joined: Jun 04, 2005 Posts: 19991 Location: West and Southwest London
Posted: Tue Nov 06, 2007 3:33 am Post subject:
If we all knew the answer to that question, there would only be one SatNav manufacturer, the others would have all gone broke!
You have to think of the maps and the GPS as a single thing. The routing algorythms use data embedded in the map to decide on whether one route is faster or shorter than another.
Different manufacturers will give you a different amount of control over how it makes its decisions. TomTom for example only give you the choice between fastest route, most direct, avoiding motorways, walking or cycling routes or a limited speed. It doesn't give you any control over your preferences for each type of road. Others do, but TT is still the market leader so it isn't a simple decision.
Joined: Aug 31, 2005 Posts: 15158 Location: Bradford, West Yorkshire
Posted: Tue Nov 06, 2007 10:26 am Post subject:
plus as well, even though 2 companies buy the map data from the same source there have been occasions (tomtom) where to make the maps physically smaller, a lot of small roads were removed and bendy roads straightened...
basically, gps manufacturers can still 'change' the maps.
as for route types, iGo MyWay 8 (not yet released, should be soon) has a handy one: "easiest route" - i.e. not neccesarily the fastest or shortest BUT it's got the least turns so keeps you on the same road as long as possible. useful in cities you don't know too well that have lots of nasty junctions.
personally i prefer garmin's routing over tomtom's but i know that some people have had issues with garmin nuvi 'loving the back roads'...
it's personaly preference really but what you have to remember is that it WILL get you to the destination - if you know a better route then take it and let the sat nav recalculate or, don't even use one if you know where you're going ;)
Joined: Feb 01, 2006 Posts: 2543 Location: Rainham, Kent. England.
Posted: Tue Nov 06, 2007 6:06 pm Post subject:
Quote:
as for route types, iGo MyWay 8 (not yet released, should be soon) has a handy one: "easiest route" - i.e. not neccesarily the fastest or shortest BUT it's got the least turns so keeps you on the same road as long as possible. useful in cities you don't know too well that have lots of nasty junctions.
iGO 2006+ has Fastest, Shortest and Economical modes. By adding an extra line, can't remember how, you can, I believe, get the equivilent of Easiest.
A majority of the major routing limitations and errors nowdays are caused by map data issues. The algorythms used will produce different results, which will be turned into reglious arguments by those who have strong opions or commercial interests at stake.
Until recently the avalible data storage has be much less than required to store all the avalible map data on a device (Say all of Europe). The manufacturers had to compress this, and remove stuff that may have been useful on rare occations, and only keep the really important stuff. Some removed more than others, and therefore have less information to work with, although the difference is not great. Also large amounts of information is not currently published, so some really usedful stuff is not avalible (Average speed over a section of road is not known)
The most common complaint is the "I know it's faster to go the other way" - well, in that case you go the other way. The SatNav does not have the same detailed local knowledge you do, and never will have.
The other complaint is the "Theres a new road and the SatNav doesn't know about it" - the data takes upto 2-3 years to filter into devices. TomTom have a solution for this (Mapshare), but it's too new to know how good it really is, and you have to remember to update your Satnav.
One thing missing from SatNavs is temperal data. Everyone knows traffic flows are different at 5PM from 3AM (Except the navigation industry). The Nav industry is hanging it's hat on real time traffic for this, but RTT is the answer for exceptions, not the norm - What's a traffic jam at 3AM on the M1 is normal traffic at 8AM. The Satnav should know that at 8AM the average speed is 5m/hr and 3AM its 100..... When planning long routes, this adds complexity as the time at a point determines the speed - calculating optimal long routes becomes difficult.
Joined: Aug 31, 2005 Posts: 15158 Location: Bradford, West Yorkshire
Posted: Wed Nov 07, 2007 2:36 pm Post subject:
robertn wrote:
One thing missing from SatNavs is temperal data. Everyone knows traffic flows are different at 5PM from 3AM (Except the navigation industry). The Nav industry is hanging it's hat on real time traffic for this, but RTT is the answer for exceptions, not the norm - What's a traffic jam at 3AM on the M1 is normal traffic at 8AM. The Satnav should know that at 8AM the average speed is 5m/hr and 3AM its 100..... When planning long routes, this adds complexity as the time at a point determines the speed - calculating optimal long routes becomes difficult.
Thats excellent news, it will take a while before the main stream manufacturers (TomTom, Navman, Garmin) are able to intergrate the information and modifiy their algorythms to make use of it. I look forward to the first devices coming out with it avalible.
Joined: Jun 04, 2005 Posts: 19991 Location: West and Southwest London
Posted: Wed Nov 07, 2007 11:11 pm Post subject:
SatNavs are really still in their infancy. In ten years time, I'm sure we'll look back an laugh at the primitive hardware and software we are having to use now.
Joined: Feb 01, 2006 Posts: 2543 Location: Rainham, Kent. England.
Posted: Thu Nov 08, 2007 12:10 am Post subject:
Quote:
SatNavs are really still in their infancy. In ten years time, I'm sure we'll look back an laugh at the primitive hardware and software we are having to use now.
I thought the main idea of Sat Nav was to navigate us from A to B via C, D, and E if necessary. Apart from some mapping errors they do their job quite well.
The ETA's work well, usually arrive within a minute or two of the estimation, but if you stop for fuel or food or break down or have an accident, how can they ever be 100% when first set up before leaving home?
If I'm going on a longish journey and plan to have a couple of one hour stops, I just add two hours to the initial ETA. After the last stop the ETA becomes pretty accurate if the run is uneventful.
Maybe some software is worse than others. I've only had experience of TT3 and 5 and iGO 2006+ and never had any real problems, especially with the latter.
Joined: Jun 04, 2005 Posts: 19991 Location: West and Southwest London
Posted: Thu Nov 08, 2007 12:24 am Post subject:
I'm talking about things like real time traffic and accident info (that works), accurate mapping instantly updatable directly to the unit on the road, intelligent POIs with full info, images etc, vastly improved voice recognition and TTS, real 3D mapping or true photo-realistic modelling of buildings.
Individual road (and road type) preferencing, optimised multi-drop itineraries, smooth scrolling and no urban canyoning.
Joined: Feb 01, 2006 Posts: 2543 Location: Rainham, Kent. England.
Posted: Thu Nov 08, 2007 12:47 am Post subject:
Quote:
I'm talking about things like real time traffic and accident info (that works), accurate mapping instantly updatable directly to the unit on the road, intelligent POIs with full info, images etc, vastly improved voice recognition and TTS, real 3D mapping or true photo-realistic modelling of buildings.
Individual road (and road type) preferencing, optimised multi-drop itineraries, smooth scrolling and no urban canyoning.
Not asking a lot then?
POI's with images? Voice recognition? As in 'Shut up you stupid TomTom'! Real 3D mapping? iGO 8 has made a start with that. Optimised multi-drop can be done on iGO 2006+ but cannot be saved at present. But it's easy to set up a separate group of Customer POI's to use as and when required.
My needs are simple, A to B but if a software company can come up with a device that suits everyones needs they will surely corner the market.
TomTom appears to rule at the moment but keep an eye on iGO.
Joined: 24/06/2003 00:22:12 Posts: 2946 Location: Escaped to the Antipodies! 36.83°S 174.75°E
Posted: Thu Nov 08, 2007 11:11 am Post subject: Re: Newbie Question: Routing Algorithims
Shimon wrote:
If so, who has the better reputation and who is less reliable?
You will get a lot of answers to that question! I think they probably all have their pros and cons and it would be difficult to choose the "best" one.
There ARE some things to understand though:
The maps will have errors in them. Generally, the more up to date the maps are the better, though just because you have the latest maps doesn't mean that every road will be present and correct. Your shiny new GPS will tell you to do something illegal/dangerous/stupid from time to time - you just have to use your good judgment and not follow it's instructions blindly.
Someone with local knowledge will always think the sat nav is wrong. Sometimes they are actually right too. Other times you see a look of surprise on their faces as the sat nav takes you a route that they hadn't considered using and it turns out to be quite quick...
Sat nav systems aren't great at knowing what traffic conditions are like. They will think it's a good idea to route you though the middle of Croydon on a Saturday or naively presume that you can average 70 MPH on the M6 or M25 at 5pm on a Friday.
Garmin units have an issue whereby they think that you can average 60 MPH on unclassified roads (often single track country lanes) and will route you down the lanes in preference to an "A" road which is slightly longer. There is a long thread Nuvi 350 - Loves the back roads! with a discussion of the problem. It catches you out from time to time, especially if you drive between small villages in the country but it's not all that bad in my opinion.
Garmin and TomTom are both pretty good, make your choice and be prepared to live with their limitations and you will be fine. People who hate gadgets will always find fault with them but at midnight on a cold rainy night when everyone in the car is tired out they will think it's a life saver when it takes you right to the door of your destination. _________________ Gone fishing!
Too right - they only just answer the question "How do I get there". With some obvious improvements as technology improved, it can get incrementally better.
The real question that when answered, will provide the next revolutionay shift this market, is "What are you doing when you get there". The answer to this questions determines, in many cases, the travel options that are relivent. If you are going to a party, stop at a grog shop on the way, the park for a picnic- maybe a supermarket or deli, the Mother-In-Laws - a gun shop
I have a 1 year old child with me and he's hungry and I have no nappies left, I don't want to be looking for a POI called "walmart" - heck, I am in a strange country I wouldn't know a porn shop from a chemists without looking in the window. I want to be looking for somewhere I can buy Nappies - a service or product, not a place. This problem is more common for me than wanting a particular place. Incorporate the yellow pages into the devices (online prefered) - send my GPS pos to the yellow pages with my requirement. It sends back a list of places that are close that meet that.
Now add this to trip planning - I am going for a picnic, sometime between leaving and arriving, I need to stop to get some cold beer, meat and sauages, and I need to get Gas for my BBQ. The device looks all this up, and calcualtes a route that incorporates all these.
My trip is a long one, spanning 8 hours, I will need to stop for food, water and petrol along the way, wheres the best place to stop for each - the car fuel computer is hooked inot the Nav device, It can get you to the "best" petrol station. It locates eateries you will be close to around 6PM etc.
Now think about the advertising and brading that can go on here. I see the furture as FREE maps and devices, funded through the product (and service) "placement" in the route navigation - Golly, my Satnav seems to prefer to route me past a McDonalds, at dinner time [Theme to Twilight Zone playing quitely in the background]......
And you thought these latest products had done it all with real time traffic information......
Joined: Dec 28, 2005 Posts: 2003 Location: Antrobus, Cheshire
Posted: Fri Nov 16, 2007 6:45 pm Post subject:
robertn wrote:
Quote:
SatNavs are really still in their infancy.
Too right - they only just answer the question "How do I get there". With some obvious improvements as technology improved, it can get incrementally better.
The real question that when answered, will provide the next revolutionay shift this market, is "What are you doing when you get there". The answer to this questions determines, in many cases, the travel options that are relivent. If you are going to a party, stop at a grog shop on the way, the park for a picnic- maybe a supermarket or deli, the Mother-In-Laws - a gun shop
And this is going to be with us in the very near future - initially offered by your mobile network supplier - you didn't think the mobile companies were selling us 'phones with GPS in them for our benefit did you?
Not that they need GPS of course as GSM location (especially in towns and cities) is close enough for these purposes. _________________ Phil
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eagerly awaiting it's release this month!
Other times you see a look of surprise on their faces as the sat nav takes you a route that they hadn't considered using and it turns out to be quite quick...
