determining poi travel direction

Not quite sure exactly what you are asking, but I think you are asking, "Do you have to be going a certain direction for a poi to alert". Is that right?

If so, yes. The POI must be on the same route as you are traveling and must have an alert set up. There are many ways to do this. There are tons of threads on how, just do a simple search.

i understand that you must be traveling on the road the poi is on, but is the poi direction of travel specific? ie: if there is a red light camera looking southbound on main st, and i am traveling north bound, will the gps alert me since the poi is for south bound traffic. and also, if it is direction specific, how do i set that up in my poi files?

User created Custom POI alerts on Garmin units are not directional.

Check out Phil's great guide for more information about alerts.

Hornbyp's guide to setting alerts with POI Loader
http://www.poi-factory.com/node/6764

MM is correct (as usual). I have even tried zooming way in and placing a POI in the southbound lane of a divided highway where the N+S lanes are actually separated by a significant distance hoping the alert wouldn't go off in the northbound lane. It didn't work.

GDFAINI:

I sort of have to disagree with you in some respects.
I make directional POIs on divided highways such as interstates using the TourGuide function. I place the POI location and set the proximity to approx. 50 feet. I use this on my Rest Area POIs and am only alerted for the rest area ahead in my direction of travel. I usually place it location approx. 1 mile ahead of the off ramp with a voice alert saying "Rest Area Ahead approx in 1 Mile."

I also tested this our on 31w going through Fort Knox Ky. 1 POI for northbound saying the "FORT KNOX GOLD VAULT IS ON YOUR RIGHT", and 1 for the southbound saying "FORT KNOX GOLD VAULT IS ON YOUR LEFT".

I found that all DIVIDED highways including Interstates work using this method.

I use MapSource to make the GPX POI file. I set the proximity value to " .001 " this is approx 53 feet.

I tried this in normal 2 way roads, both 2 and 4 lane and found I could not get very good results. But it works great on DIVIDED roads.

H Hannah
Nuvi750 and IQUE3600

Yeah, but TourGuides are different from regular POIs.

If you want to see a TourGuide that works using the above reply look at:

http://www.geovative.com/GeoTours/Xchange.asp

And use Road Trip as KEY and Kentucky as Location the Search then pick FORT KNOX GOLD DEPOSITORY.

H Hannah
Nuvi750 and Ique3600

MM:
They are POIs just the same as Speed, Redlights and all others. And they WORK.

H Hannah

I think that's the key point - The accuracy of the received signal, the tolerance allowed and the precison of the points making up the road, will all come into play.
Sometimes, a divided highway is defined in the map, as two parallel roads, which would no doubt influence the results as well.

The POIs might be similar (they aren't exactly the same), but the alerts are different. As Phil explains in his guide to setting alerts, TourGuides appear to work as a radius while regular alerts don't. And many people do not have the ability to create TourGuides and not all units support their use.

MM is correct, most of the older units, such as the C330 & C340, do not support Tourguides.

I realize that not all garmin GPSs can use TourGuide POIs. But those that do can use this workaround and make some of thier POIs directional.

I was only responding to GDFAINIs statement

"MM is correct (as usual). I have even tried zooming way in and placing a POI in the southbound lane of a divided highway where the N+S lanes are actually separated by a significant distance hoping the alert wouldn't go off in the northbound lane. It didn't work."

And My responce was "I sort of have to disagree with you in some respects."

See NOT ALL respects!!

Those that do have the capablities to use TourGuides might want to know about this procedure.

Also MM, I know some alerts work differently than others. Thats why I told you just how to use them to make them work in this case!!!!

Just because it says TourGuide does not mean it can only be used for a TourGuide. I also use TourGuide for my school zones. This makes sure I get an alert set by distance that I control and not bothered by speed.

I am sure you all could exxperiment with the different type alerts and come up with other ways to use them to your advantage.

H Hannah

My own personal experience is that for a POI file I made of local school zones (yes I have the downloaded version from here as well) that I get alerted to a school zone if I am within the alert distance and am traveling so that I could possibly turn into that zone even if I am not on the street of the alert.

In other words, say I am traveling down Main Street and intersecting with Main is School Rd a block or two ahead. And School street has a 20 MPH zone right near that intersection. As I approach School Rd. while traveling on Main, I WILL be alerted to the school zone when I get within range, despite NOT actively driving on School Rd. but because my travel direction includes the possibility I may turn down School Rd.

However once I pass School Rd. and didn't turn down it, the alarm on my nüvi 200 stops as I am no longer on route to go down that street.

PT

Your reason could well be correct. Or, it could be that your route shares a common point with both Main St and School Rd (the intersection) and because at that point the system sees you as being on both roads, you get the alert. A quick check of that would be to place an alert on a street that intersects School Rd. That would still allow for the possibility of you going past the school (with 2 turns), but no point on your chosen route would be common with the street having the POI. If it still alerts, your reasoning would be proven accurate.

I am a bit new to this, but I believe all proximity alerts work on a radius basis. I have been doing an experiment for the past week or so and have concluded that, if you set a proximity alert for 0.1 miles or about 528ft, AND set your alert settings to alert ONCE and not CONTINUOUS, you get a quasi-directional alert. It seems to work, only alerting me as I approach (once or twice- so much for alert once), but not after. Great for safety cameras. Hope this helps. BTW, it can be done by setting the proximity alerts with Mapsource or the POILoader, have done it both ways, but I think barring any major improvements to GPS programming, this can accomplish the same thing, Later.

There may be a semantic problem here.

A TourGuide (with alerts on) will let you know whenever the POI is within the "radius" of a circle with your GPS at the center - regardless of the direction of your travel at that moment.

Red-light alerts occur "along the route" and ahead of you.

I think you used the term "radius" to mean in front of you but "along the route". The POI can be some 30 meters to either side of "along the route" so that might seem like a radius. Is that what you were finding?

Have you thought of
Making the waypoints TourGuides of a 53 foot radius, placing them before the real point of interest, like you mentioned in your message,

BUT

not placing them on the road. Place them off the road to the right of the direction of travel by some distance (say 53-100 feet [you'll have to experiment]).

You would, of course, have to use a good map program to determine the exact 'off road' coordinates to use but that is not an impossible task.

This would have made a good article for the Garmin Tricks website. When you experiment and figure it out -- please write it and I'll publish it under your name.

Gary Hayman

For the situation you describe, the circle would be centered on the poi, not the gpsr.

A ‘radius basis” implies that circles are involved. Tour Guide POIs are the only type that would have circles associated with them.

There are two types of circles associated with Tour Guide POIs.

Type 1 comprise circles centered on each Tour Guide POI. The radius of each Type 1 circle is the alert distance for the individual POI. These could be plotted on a map and would remain fixed for a given set of POI locations and alert distances.

A Type 2 circle is one that could be drawn at any instant in time, centered on the GPSr, with a radius equal to the maximum allowed alert distance (200000 feet or 65000 meters). It is sort of like a radar screen sweep circle. You could plot a Type 2 circle on a map for each instant of time.

Plotting Type 2 circles over a period of time would effectively result in a band, with a width of 400,000 feet, centered on the path taken by the GPSr.

The GPSr is continuously searching for Tour Guide POIs within the Type 2 instanteous circle and then checking to see if any of those have alert distances equal to or less than the distance from the GPSr to the POI.

The effect is that a Tour Guide alert will trigger when the GPSr is within a Type 1 circle.

I wrote that backward.

As you say, the circle is logically centered on the POI.

So when I write a poi for rlc's in mapsource, I see every coordinate I entered with a proximity point inside a red circle. The size of the circle depends on what distance I set the proximity alert. Is this actually a tour guide then? I didn't thinkso, but as I said before, I am new to this. Either way, after further experimentation, it seems to work as I stated earlier, with the alert only sounding on approach and not after, as long as it is on a route of travel. To jgermann: I don't think I was doing a tour guide alert because I haven't researched those yet. Or am I????

I find one has to balance the approach used, based on the level of annoyance.

Red Light Camera warnings can be more annoying, that a Rest Area warning, since you potentially run into them a greater frequency, than a rest area. You likely only come across a Rest Area every 2-3 hours on a road trip on an interstate. I set the proximity alert about 1 1/2 to 2 miles and I do get an alert for the Rest Area on the other side of the median, fairly often. It's a minor annoyance and does not last for long. It also only applies on major highways, that actually have Rest Areas.

However, in a city with a number of RLC, you could have alerts every 10-30 minutes. If I create the RLC for my own use, I move the the actual location of the RLC a few hundred feet before the actual RLC and then set a proximity alert of about 30-50 feet. In most cases that makes it very directional.

What you have to realize is that there are Vehicle type GPSr units and there are Off Road type GPSr units. Terminology is some what different within each type. For example location of points are called Point(s) of Interest (POI) in the Vehicle realm and are called WayPoints in the Off Road realm.

My statement “Tour Guide POIs are the only type that would have circles associated with them” applies to the realm of Vehicle Type units. (Note that terms such as “Red Light”, “Speed Camera” and TourGuide” imply that the context of discussion is in the realm of Vehicle type units.)

Mapsource originally dealt only with the off road type. Since all Off Road waypoints could likely be approached from any compass direction Mapsource shows proximity circles around waypoints.

Mapsource does not deal directly with the concepts of proximity alerts associated with Red Lights, Speed Cameras, TourGuides etc. You will not find any of those terms in Mapsource help.

There is no way to tell Mapsource that waypoints are to be associated with any of those terms. When you save a file there is no choice in the Save As dialog box drop-down-lists to indicate any of those terms. Those terms do not appear anywhere in the waypoint definition boxes.

Mapsource can send waypoints with proximity alerts directly to Off Road units.

For Vehicle types you have to save the file as a .gpx file and then use Poi Loader to load it. (you could save it as a txt file and then convert that to a csv).

So the bottom line is: Mapsource has no idea of what type it is and it is not “actually a “tour guide” until you put “TourGuide” in the file name as you save it or otherwise deal with it after it is saved.

That is well and good but realize what the original poster meant by “directional” is that different action is wanted when a poi is being approached from different directions.

I will have to review the concept but IIRC it is normal for a proximity alert to sound as you approach the point and not sound after you pass it.

OK, thanks. Guess I have a bit more work to do. Anyway, I originally said "quasi-directional", meaning not really directional, but it works similarly, as sort of a simple work around. Maybe not as advanced, but give it a try, see what you think. Just trying to afford a work around for those of us who are not as "experienced". Thanks for the info, lot of great comments on this forum. L8r!

If a road shows up as 2 lines in Mapsource, you can create directional warnings.

Create a waypoint anywhere near this two road lines, enter the proximity distance first as 0.030 meters.
Very important: Zoom in to maximum - 20m.

Now move the waypoint so that the circle lines are over the prefered road, but not on or touching the opposite going road. For a start halfway will be good, but by experimenting, you will know how close you can move this circle towards the other road before getting false warnings.

Now you can change the proximity to what ever you prefer ie. 0.850m and save as "named.gpx."
Load the usual way with PoiLoader.

It all comes down to the fact that you must violate this 30 meter radius before getting a warning. If you create a waypoint as above, but put it off the road so that the circle lines are not on or touching the roadlines, you will not get a warning - even if the proximity distance is set to 10,000 meters.

Read my small article over here:

http://www.garmap.co.za/forum/uploads/5949/Waypoint_Updated....

I have made a Red Light POI that is specific to the Municipality, where I live. I use Extra POI Editor, go to satellite mode and drag the point back up the road a good 50 or 60 feet or more and right against the curb or even onto the boulevard. If the road is two lanes, both directions, I'll use about a 45 foot alert distance, which isn't wide enough to cross into the opposite lanes, by much. If it's one lane each direction, it's darned near impossible to stop it from triggering from the wrong direction.

It works, but it sometime takes a bit of playing, by actually driving to the spot and seeing what happens. In many cases, it just ain't worth the extra effort.

I assume you are aware of the possibility to create directional poi with EPE using cicle list to set the alert zone.

In devided road you make the alertzone on the road you want the alert, and in a road with both way driving direction you put the Poi in the middle of the road and the alert zoone (circle list) on the side you want the alert. Driving over the alertzoone (circles) before poi gives alert, driving over poi before the circles turnes of the alert before reaching the alertzoone. It have to be 2,5 seconds space between Poi and first circle radius to let the poi have enough time to turn of before reaching alertzoone. The cicles have to be inside the proximity of the Poi.
Note:EPE are still limited in some points of creating gpi files.

@davidkbrown
please post the coordinates of that poi so I can have a look.

Just remember, the 30 meter radius I am talking about, is NOT the actual proximity distance that you set for getting an alarm