Home PageFacebookRSS News Feed
PocketGPS
Web
SatNav,GPS,Navigation
Pocket GPS World - SatNavs | GPS | Speed Cameras: Forums

Pocket GPS World :: View topic - Garmin Proximity Alerts
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log in for private messagesLog in for private messages   Log inLog in 

Garmin Proximity Alerts
Goto page 1, 2, 3  Next
 
Post new topic   Reply to topic    Pocket GPS World Forum Index -> Garmin Portable Navigation Devices
View previous topic :: View next topic  
Author Message
Kremmen
Pocket GPS Verifier
Pocket GPS Verifier


Joined: Mar 03, 2006
Posts: 7037
Location: Reading

PostPosted: Sat Apr 23, 2011 7:19 am    Post subject: Garmin Proximity Alerts Reply with quote

I'm in the process of creating a program to write out .gpx files to override the Garmin default of 36 seconds as this setting pulls in cameras on adjacent roads and is therefore too broad.

I've cracked 99% of it and I have a working version.

My final problem is trying to understand how the POI Loader deals with proximity alerts.

Having read various articles I initially put 'feet' into the data field as that is the POI Loader setting I was using. This was clearly wrong as I was getting warned of cameras up to three quarters of a mile away!

I then read a few more articles and it seems that POI Loader uses Metres by default even though you have selected 'MPH and Feet'. This setting was more accurate but still not right as the alerts were now too close.
Next step was to use yards instead of metres which is better but still not right.

Example:

I've set my' Approach' figure to 15 seconds. Travelling at exactly 30 mph approaching a 30 Gatso, as soon as the alert triggers I've timed the seconds and it's 12, not 15. similarly at 50 mph the alert is triggering slightly too close.

My calculation is based on 15 seconds at 30 mph distance covered = 0.1250 of a mile = 220 yards or 201.168 metres.

= POI Loader has a mind of its own Sad

I'll get there Smile
_________________
Satnav:
Garmin 2599 LMT-D (Indoor test rig)
DashCam:
Viofo A119 V3
Car Average MPG :
Back to top
View user's profile Send private message
BigPerk
Frequent Visitor


Joined: Sep 06, 2006
Posts: 1618
Location: East Hertfordshire

PostPosted: Sat Apr 23, 2011 9:44 am    Post subject: Reply with quote

Just a thought - have you tested the Garmin 36-second default in the same way? Wondering if that's correct or a little bit out as well?
_________________
David
(Navigon 70 Live, Nuvi 360)
Back to top
View user's profile Send private message
dales
Frequent Visitor


Joined: May 04, 2008
Posts: 752
Location: Knaresborough, North Yorkshire.

PostPosted: Sat Apr 23, 2011 11:42 am    Post subject: Reply with quote

Just a thought - have you tried the Ash10 CameraManager utility? This allows the user to set warning times (and overspeed warning times) for each type of camera.

And yes, the values produced by Ash10 in the gpx files do not exactly tally with those expected by simple maths - there is clearly something more to the calculation that I haven't grasped.

Dales.
_________________
nuvi 2599LMT-D, oregon 700, basecamp, memory-map.
Back to top
View user's profile Send private message
PhilHornby
Frequent Visitor


Joined: Dec 07, 2006
Posts: 563
Location: North Devon

PostPosted: Sat Apr 23, 2011 2:34 pm    Post subject: Re: Garmin Proximity Alerts Reply with quote

Kremmen wrote:
My final problem is trying to understand how the POI Loader deals with proximity alerts.

I then read a few more articles and it seems that POI Loader uses Metres by default even though you have selected 'MPH and Feet'.

For some reason, Garmin used the weird '@speed' construct in GPX files and then needed to add a dialogue to find out what units it is in. The other entries in the GPX file are in metric units and the POILoader setting has no effect on their interpretation. (Why Garmin did this, is one of life's little mysteries Wink )

and he wrote:
I've set my' Approach' figure to 15 seconds. Travelling at exactly 30 mph approaching a 30 Gatso, as soon as the alert triggers I've timed the seconds and it's 12, not 15. similarly at 50 mph the alert is triggering slightly too close.

Could this just be due to inaccuracies in the way you've measured exactly 30mph and 12 seconds? Speedo error and counting 'elephants' or 'mississippis' might do it Smile

It might even be a firmware bug in your device...

Quote:
My calculation is based on 15 seconds at 30 mph distance covered = 0.1250 of a mile = 220 yards or 201.168 metres.

Looks good to me...

Quote:
POI Loader has a mind of its own Sad

Correct! Rolling Eyes (and Garmin sometimes introduce undocumented changes between versions)


Last edited by PhilHornby on Sun Apr 24, 2011 7:08 pm; edited 1 time in total
Back to top
View user's profile Send private message
MaFt
Pocket GPS Staff
Pocket GPS Staff


Joined: Aug 31, 2005
Posts: 15126
Location: Bradford, West Yorkshire

PostPosted: Sun Apr 24, 2011 12:58 am    Post subject: Reply with quote

Personally I just use CBROM's GPS Convertor... Have you given this a try?

MaFt
Back to top
View user's profile Send private message Visit poster's website
Kremmen
Pocket GPS Verifier
Pocket GPS Verifier


Joined: Mar 03, 2006
Posts: 7037
Location: Reading

PostPosted: Sun Apr 24, 2011 6:35 am    Post subject: Reply with quote

Thanks for the feedback Smile

As far as speedo accuracy is concerned I used the Garmins own speed on a few occasions which differs from my cars digital speedo by circa 2mph at 50 so hopefully I can rule that one out.

I have considered other existing apps but being a developer I want to see if I can do my own.

I have looked at the data of others and I suspect the same may occur as the proximity settings are roughly the same?

I've tried 2 different 'name' formats, one with the @ and one without and that doesn't make any difference as it looks like the 'proximity' setting holds the key.

Once I've cracked this item with a % add-on my next project is to try and remove some of the 'duplicates' where there is a camera on both sides, being as Garmin have omitted a directional facility from their Loader.

On the M25 for example the cameras are on adjoining gantries. This triggers 2 warnings. What I'm finding is that the 'alerts' seem to get stacked up. A second alert will not trigger until the first has finished. This seems to have the effect of sometimes producing the second warning when your right on top of the camera or even just past it.

An interesting project that may take a little time to perfect.


_________________
Satnav:
Garmin 2599 LMT-D (Indoor test rig)
DashCam:
Viofo A119 V3
Car Average MPG :
Back to top
View user's profile Send private message
PhilHornby
Frequent Visitor


Joined: Dec 07, 2006
Posts: 563
Location: North Devon

PostPosted: Sun Apr 24, 2011 7:07 pm    Post subject: Reply with quote

Kremmen wrote:
As far as speedo accuracy is concerned I used the Garmins own speed...

You could try using the Nüvi in 'simulation' mode, rather than trying to measure this for real. You have no control over the speed the simulation runs at, so you may have to adjust the speed of your alerts to be lower than reality for the purpose of your tests. (I just tried a Nüvi 250W, which decided to 'drive' @28mph, thus not triggering my 30mph alerts (which are set for 35mph anyway)).

The quick test I did on the 250W, revealed that the 15 sec warning I had asked for, was being honoured. (I use ASH10's Camera Manager).

and he wrote:
I've tried 2 different 'name' formats, one with the @ and one without and that doesn't make any difference as it looks like the 'proximity' setting holds the key.

I may have misunderstood what you're saying there, but the two types of alert are definitely different. When the "@" is specified, you have to be exceeding the specified speed for the alert to trigger. The contents of the GPX {proximity} field (or the 36 sec rule) determine when the alert is considered active. When "@speed" is not present, the alert is triggered purely by distance (measured along the road, or roads making up the route).

There are some caveats: different units behave slightly differently; different firmware versions sometimes change things and some units let you set things like 'continuous' alerts. You get strange effects if you slow down and speed up within the proximity distance - such as approaching red lights - the alerts tend to re-trigger repeatedly. If alerting POIs are not within some arbitrary (undocumented) distance from your route (75' ?), they don't alert.


Last edited by PhilHornby on Mon Apr 25, 2011 6:40 pm; edited 1 time in total
Back to top
View user's profile Send private message
Kremmen
Pocket GPS Verifier
Pocket GPS Verifier


Joined: Mar 03, 2006
Posts: 7037
Location: Reading

PostPosted: Mon Apr 25, 2011 6:12 am    Post subject: Reply with quote

Thanks for that.

I have indeed noted some strange behaviour. The M25 variable alerts were almost continuous when I had the @0 within the file. When I replaced this with #0 they were less active, which is what I wanted. I've since replaced the #0 with #70 and I'm just getting the single warning. I've also noticed the behaviour you mention when you slow down or speed up within the proximity. Also, I get a Redlight warning as expected. If I stop before the lights then as soon as I set off again I get another warning. I suspect this is by design as a further reminder.

Looking at Ash's file his proximities are more or less the same as mine. His are lower, so as you say, it looks like it's firmware related. As an example, Ash has '360' for 50mph whilst mine is calculating '366' so I would expect mine to be slightly longer.

I have some rework and testing to do but I'll get there in the end. At least I know the proximities are being read in after my 'feet' goof.

One thing I have noticed, even when I was using the neat .csv file on my 2200 is that I always get the approach warning, regardless of speed, unlike some reports of no warnings at all when under the limit. I wonder if Garmin have responded to criticism?

I have downloaded the latest 3.0 firmware.

Thanks for the simulation mode tip, never thought of that Smile
_________________
Satnav:
Garmin 2599 LMT-D (Indoor test rig)
DashCam:
Viofo A119 V3
Car Average MPG :
Back to top
View user's profile Send private message
dales
Frequent Visitor


Joined: May 04, 2008
Posts: 752
Location: Knaresborough, North Yorkshire.

PostPosted: Mon Apr 25, 2011 12:07 pm    Post subject: Reply with quote

I may have misread it, but your prog looks to me as though the Redlights are all set for a warning proximity corresponding to 30mph.

But in the database, there are Redlights at all sorts of speeds, 20...30....40...50....0 mph.

Just an observation

Dales.
_________________
nuvi 2599LMT-D, oregon 700, basecamp, memory-map.
Back to top
View user's profile Send private message
Andy_P
Pocket GPS Moderator
Pocket GPS Moderator


Joined: Jun 04, 2005
Posts: 19991
Location: West and Southwest London

PostPosted: Mon Apr 25, 2011 1:29 pm    Post subject: Reply with quote

The speed data is recorded for "plain vanilla" Redlight cameras (as opposed to combined Redlight and speed), but it isn't necessarily used.

I'm not sure if Garmin/Ash's program uses the speed number in the individual camera's name or not, but other brands just have all the Redlight cameras in a single file, so they would always have the same warning distance irrespective of the speed limit in force.

"Red/speed" cameras are split up into the individual speed-limit categories though.

There is the argument/opinion that while it is possible to miss a well-hidden camera through slight inattention, there's absolutely no excuse for missing a set of traffic lights at red, so we are lucky to have the ordinary red-light cameras in the database at all!
Back to top
View user's profile Send private message
PhilHornby
Frequent Visitor


Joined: Dec 07, 2006
Posts: 563
Location: North Devon

PostPosted: Mon Apr 25, 2011 6:40 pm    Post subject: GPI contents Reply with quote

Kremmen wrote:
I have indeed noted some strange behaviour. The M25 variable alerts were almost continuous when I had the @0 within the file. When I replaced this with #0 they were less active, which is what I wanted.

I have a copy of Garmin's GPI_Viewer tool (obtained as part of the Content Toolkit and sadly, not for re-distribution). This makes it easier to see what makes it into the .GPI file, using various input parameters.

POILoader (or at least V2.6.0.0 that I'm using), is clever enough to know that "Name@0" is nonsense - it doesn't set an alert of any sort, based on a min. speed of zero. The same is not true of {proximity}0{/proximity} (even though it's kind of wacky, this sets a distance-based alert at exactly 0 metres (or feet ;-).

In the absence of GPI_Viewer, you can tell from the default audio if you're hearing a speed or distance-based alert. Distance alerts use "Passive Tone", which is a lower-pitched "Bong,Bong". Speed alerts use "Aggressive Tone", which is a higher-pitched "P-i-n-g".

Note: when experimenting with any of this, beware the use of 'magic' words (and numerals) in your POI file names (Gatso, Redlight,Speed etc). These will silently override all your settings! (Eye-of-toad, leg-of-newt programming: giving different results depending on the phase of the moon & state of the tide ;-)

and he wrote:
Looking at Ash's file his proximities are more or less the same as mine. ... As an example, Ash has '360' for 50mph whilst mine is calculating '366'.

EDIT: FWIW, I calculate that a setting of 366metres gives a delay of 16.374 secs and 360 gives 16.106 secs @50mph Very Happy
(The uncertainty in the computed GPS fix is probably more than 6 metres anyway...)

I can tell you, that left to its own devices, when POILoader encounters @50 (in Imperial mode), it writes a proximity of 805m and a speed of 2235cm/sec to the .GPI file. (ie it defaults to 36.018 seconds).

Quote:
One thing I have noticed, ... is that I always get the approach warning, regardless of speed, unlike some reports of no warnings at all when under the limit. I wonder if Garmin have responded to criticism?

I've seen that effect on some unit or other in the past. Personally, I don't like it, because that's not what they document it as doing...


.
Back to top
View user's profile Send private message
Kremmen
Pocket GPS Verifier
Pocket GPS Verifier


Joined: Mar 03, 2006
Posts: 7037
Location: Reading

PostPosted: Tue Apr 26, 2011 6:39 am    Post subject: Reply with quote

Thanks Smile

Your simulation suggestion was spot on. I did a few 'runs' across known cameras and in all cases where the simulation was at the prevailing speed limit the timing was 16 seconds. This was achieved under better circumstances as I had my eyes on the unit instead of the road and I used a proper stopwatch. Based on this I'm going to back off to Metres and re-test.

I'm happy with this and I can move forward and as I said I'm going to try and cut out duplication where the same camera type is on opposite carriageways thus avoiding the double warnings.

ps: does the .gpi interrogator give any clues to the Cyclops directional info ?

Slowly but surely, onward and upward........
_________________
Satnav:
Garmin 2599 LMT-D (Indoor test rig)
DashCam:
Viofo A119 V3
Car Average MPG :
Back to top
View user's profile Send private message
MaFt
Pocket GPS Staff
Pocket GPS Staff


Joined: Aug 31, 2005
Posts: 15126
Location: Bradford, West Yorkshire

PostPosted: Tue Apr 26, 2011 10:00 am    Post subject: Reply with quote

Kremmen wrote:
ps: does the .gpi interrogator give any clues to the Cyclops directional info?


seconded!
Back to top
View user's profile Send private message Visit poster's website
Kremmen
Pocket GPS Verifier
Pocket GPS Verifier


Joined: Mar 03, 2006
Posts: 7037
Location: Reading

PostPosted: Thu Apr 28, 2011 3:51 pm    Post subject: Reply with quote

Program output now in final testing and "the jobs a goodun" Very Happy

Proximity alerts now behaving as expected.
Ability to remove most duplicate warnings caused by Garmin not allowing directional POI's via POI Loader.
Built in unzip feature.
Approach and/or Overspeed alerts.
[/list][/list]
_________________
Satnav:
Garmin 2599 LMT-D (Indoor test rig)
DashCam:
Viofo A119 V3
Car Average MPG :
Back to top
View user's profile Send private message
MaFt
Pocket GPS Staff
Pocket GPS Staff


Joined: Aug 31, 2005
Posts: 15126
Location: Bradford, West Yorkshire

PostPosted: Thu Apr 28, 2011 5:21 pm    Post subject: Reply with quote

Kremmen wrote:
Proximity alerts now behaving as expected.
Ability to remove most duplicate warnings caused by Garmin not allowing directional POI's via POI Loader.


How does this work then?

MaFt
Back to top
View user's profile Send private message Visit poster's website







Posted: Today    Post subject: Pocket GPS Advertising

Back to top
Display posts from previous:   
Post new topic   Reply to topic    Pocket GPS World Forum Index -> Garmin Portable Navigation Devices All times are GMT + 1 Hour
Goto page 1, 2, 3  Next
Page 1 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Make a Donation



CamerAlert Database

Click here for the PocketGPSWorld.com Speed Camera Database

Download Speed Camera Database
22.034 (27 Mar 24)



WORLDWIDE SPEED CAMERA SPOTTERS WANTED!

Click here to submit camera positions to the PocketGPSWorld.com Speed Camera Database


12mth Subscriber memberships awarded every week for verified new camera reports!

Submit Speed Camera Locations Now


CamerAlert Apps



iOS QR Code






Android QR Code







© Terms & Privacy


GPS Shopping