Does the new maps update also updates or changes Route calculation?

 

I updated new maps on my devices. I have noticed that after the map update on my Nuvicam, it calculates routes differently now. For example, while going to work in the morning, on highway 401 Eastbound, it used to ask me to take Dufferen Street exit but I always take next exit Allen Road. Now after the map updates, it started asking me to take Allen Road exit now. Even in the evening, it calculates route differently after the update. Any thoughts?

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Iphone XR, Drivesmart 61,Nuvicam, Nuvi3597

Not method of calculation but data

The map update changes data which is used by the routing calculation to decide what path to propose to you. Most likely one or many more segments of the roads the routing calculation is considering in the cases that you cite were changed by the update in a way that change the predicted travel time on that segment.

The actual routing calculation is part of the firmware which Garmin terms software, so unless you were alerted that you were getting a software update, that did not change.

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personal GPS user since 1992

Just guessing

This sounds very possible. To my way of thinking the most likely causes could include slight roadway variations, speed limit changes, changes to traffic signals, and many other things. This will occur most often when there are two or more routes that are nearly identical in outcome (nearly the same elapsed time when choosing Fastest Navigation, nearly the same distance when choosing Shortest Navigation, etc.)

For some of the newer devices, a change in TrafficTrends would do this too.

Lastly, a wild guess. I wonder if devices that offer myTrends erases the old data and starts fresh with each map update. Any thought? A hard reset would also erase myTrends data.

Routing changes

Quite a while back, in a post from another user here, they quoted an email from a Garmin Map programmer that the routing algorithm for the latest map release did indeed have an error and it would be corrected in the next map release.

I'm assuming that the Routing algorithm is not in the map file itself, but in one of the other files that get downloaded with the map. Not every model has the same firmware.

Garmin keeps trying to improve the routing, but once in a while they make it worse.

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Metricman DriveSmart 76 Williamsburg, VA

3597?

Rookie, I noted that one of your devices is the 3597LMTHD. You didn't say which you are using but it may apply to other models as well. There is an option in settings under Traffic that allows to change route optimization between On Request and Automatic. As you are in an area that may provide traffic data, I'm speculating that the recent updates may have improved traffic functionality. As an experiment, if yours is set to Automatic, change it to On Request and see if it now offers the alternate exit on your daily commute. Inquiring minds would like to know if this a possibility.

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"There's no substitute for local knowledge" nüvi 750, nüvi 3597

My findings

Using my older 255WT in the past, I would notice the unit would route me differently from my workplace to my home certain times after doing a map update.

Example :

Map 2015.10 would route me from my workplace to my home a certain way.

Map 2015.20 would route me from my workplace to my home using a slightly different route.

Map 2015.30 would route me from my workplace to my home as 2015.10 or 2015.20

Depending on the map set, the GPS would always route me either two ways; as with 2015.10 or as 2015.20.

I always park in the same place at work, have rarely updated the units software & the 255WT doesn't have traffic trends therefore the actual map set on the GPS can change the routing algorithms. I've taken both routes and also know that there haven't been any new roads added from one map set to another.

I always check beforehand after a map update the routing from point A to point B because it will sometimes change and if so I'll add in a waypoint in order for the unit to take me a certain way.

Using the POI Factory search engine and entering "routing algorithms" you'll see that other users have noticed/encountered the same.

Cheers smile

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Nüvi 255WT with nüMaps Lifetime North America born on 602117815 / Nüvi 3597LMTHD born on 805972514 / I love Friday’s except when I’m on holidays ~ canuk

There is one thing to note.

There is one thing to note. After updating Device Software, or installing a new map, the GPS under goes a full restart. This will clear all the Trends and learned behaviors, and you will have to start over with the unit learning trends activities.

This may include your average driving speeds, routes taken that you have repeatedly taken instead of the calculated route, Traffic Trends, etc.

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Frank DriveSmart55 37.322760, -79.511267

Really?

I'm not sure that's true, only if you do a master reset I thought?

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Where there's a will ... there's a way ... DriveSmart51LMT-S, DriveSmart50LMT-D, Nuvi 2508LMT-D, 1490LMT, 1310, Montana 650T, Etrex 20

Thanks all for your

Thanks all for your suggestions. I would agree that there may be some file which gets uploaded with the maps to update routing algorithm.

@TXRVer - I did mention in my first post that I was using NuviCam. The other Nuvi 3597 is used by my wife.

Before the map update, in the evening when leaving from the Subway station parking lot to Home, it would ask me to go to Allen Road which is at least 3 kilometers away from my starting point. But now it tells me to take the road just outside the parking lot. This is a great improvement.

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Iphone XR, Drivesmart 61,Nuvicam, Nuvi3597