Accuracy of POI Locations
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12 years
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In an effort to get more familiar with my Garmin gps and practice some tips learned on this forum, I created a short 20 mile route and proceeded to see what campground POI's showed up along my route. What I discovered is that looking for POIs ALONG A ROUTE My Garmin 750 only shows those within 1 mile of the road.
HOWEVER, I also discovered that a large state campground within a mile was missing. I found it's POI located some 17 miles SW of where it should have been. And nearby was another POI that was about 50 miles west of where it should have been. Not too good a confidence builder for my first attempt at using data from POI Factory.
I know most of these POI's are entred by volunteers trying to help, but can't help wonder, since they are volunteers, how many data mistakes are made by people being tired, interrupted by kids, cell phones, etc., etc. I'm sure there is a process to notify someone of errors, but also wonder how often these errors occur and if people lose confidence in the POI databases after a couple mis-directed destinations.
I may never have noticed the misplaced POI's with my tiny screen gps. But after importing the csv file to Streets and Trips, it was fairly easy to spot the well known campgrounds in the local area. The good news is I only saw one missing from about 10 that appeared to be about where they should be.
I have 2 days experience with POI FACTORY, but have discovered 2 significant POI location errors in my first attempt at using one of the databases. My question is, ARE MISPLACED POI's COMMON? Can the databases be used with reasonable confidence for someone wanting to find a campground where expected after a tiring day of travel?
What is the goal?
These posts prompt me to ask the question: What is the goal of POI Accuracy?
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Since I do the Offbeat poi file, it can sometimes be hard to find the right spot, or to find where to mark the spot. I do try to be right on but it is hard.
Some of my rules are that anything that is in my File must have a address, and if possible a phone number.
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If anyone knows a better way to be more Accurate, I would love to hear it.
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Bob
For me, mine are restaurants and a grocery chain, so it is quite simple. I look for the place that will get you to where you will park your car after driving to the location. If it is the building, I place the mark on it. Sometimes the parking lot, or the entrance to the parking lot, depending on the way it may route you as it tries to turn from the closest road.
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I don't think there is a perfect solution unless we were able to physically confirm each location, so it is essential to have input from others to make the POIs as accurate as we can.
I suppose each of us will have a slightly different answer about accuracy, but I would like to suggest that we consider what a user of a POI file expects.
What most POI files are used for is to navigate to a specific location. For example, we are out-of-town and we want to go to a "Olive Garden" or "Red Lobster" for dinner (substitute your favorite restaurant).
Now admittedly, as Slidein has pointed out, we could just roll down our window and ask the first local we see where the place is, but what we generally want to do is to be taken to the place without problems. That means that we will be driving along unfamiliar roads and need to be taken to a point where we can see the sign.
HOWEVER, other users want to set "alerts" for their favorite POIs so that they can - on the spur of the moment, decide to pull off and visit the establishment. This means that the coordinates should permit an "alert" if possible. I say, if possible, because some potential stopping points are too far off the route (say, an interstate) to trigger the alert.
How far is too far off the route? As best we can tell, the perpendicular distance from the route can be no more than 30 meters (roughly 98 feet). Any further from the route and the standard alert will not be triggered. In this situation, the user must employ TourGuide alerts.
A tourguide alert will sound when the GPS is anywhere within a circle whose radius is the alert distance and the center of the circle is the GPS unit itself.
Consider a restaurant like Cracker Barrel. Many people consider Cracker Barrel an acceptable place to stop and eat while traveling as the food is good and reasonably priced. And - most Cracker Barrels are reasonably close to major highways so the off road time to get there is acceptable. However, one will not find many that are within 30 meters of a highway.
What does this mean? It means that a good placement of the coordinates for an establishment would be at that entrance to the parking area - if there are more than one - which is on the most "major" of the roads around the establishment. Rarely is the "front door" itself a good coordinate.
One of the nice features of Extra POI Editor (EPE) is that one can move the "marker" for the cordinates to a particular spot and use the "Grab" button to get new coordinates.
Thanks..
Thanks for the good advice. I will have to look into that.. I did try that in the past but fell short a few times. Aggg.. What to do.. oh woe is me..
I will figer this out and make the file a much better one for everyone. So far that I have look, Most of them are marked on or near the road next to the place. so that is good. There are a few that was way off that I had to remove it due not finding the right location.
Bob
Bobkz - Garmin Nuvi 3597LMTHD/2455LMT/C530/C580- "Pain Is Fear Leaving The Body - Semper Fidelis"
- yes -
To all of you people, I would like to know what do you do to get better information for your files..
Since I do the Offbeat poi file, it can sometimes be hard to find the right spot, or to find where to mark the spot. I do try to be right on but it is hard.
Some of my rules are that anything that is in my File must have a address, and if possible a phone number. If I see the mark on google, I will place the marker there and get the reading. Most of my findingins is with ExtraPoi edit and I do use the map to see if I can locate the place. This is hard since I Find alot of great places but I can not really go there. I must count on another way to find this location. If anyone knows a better way to be more Accurate, I would love to hear it.
So how do you find your location and make your poi file accurate?
Thanks for this information..
Bob
For me, mine are restaurants and a grocery chain, so it is quite simple. I look for the place that will get you to where you will park your car after driving to the location. If it is the building, I place the mark on it. Sometimes the parking lot, or the entrance to the parking lot, depending on the way it may route you as it tries to turn from the closest road.
For yours, it may not be as simple. For me, the most frustrating part is using my own POI, and then having to struggle a bit to find the location as it is not always accurate.
I don't think there is a perfect solution unless we were able to physically confirm each location, so it is essential to have input from others to make the POIs as accurate as we can.
I agree with the others, many of the POIs listed here are far better than what you can find pre-loaded.
Good plan!
~Jim~ Nuvi-660, & Nuvi-680
UP of Michigan campgrounds
What is the best way to send updated corrections concerning camp grounds in the Upper Peninsula of Michigan, A number of them that I am very familiar with are incorrect regarding coordinates. I wonder who supplied the initial information.
Is it this file?
Is it this file? http://www.poi-factory.com/node/28566
If so then contact the maintainer (rivopom) on his contact page. http://www.poi-factory.com/user/25340
Also, as you find corrections in any file, contact the maintainer.
What is the best way to send updated corrections concerning camp grounds in the Upper Peninsula of Michigan, A number of them that I am very familiar with are incorrect regarding coordinates. I wonder who supplied the initial information.
Nuvi 2460LMT.
For a while, it seemed to be
For a while, it seemed to be epidemic that acquiring satellites took a lot longer than it used to. Now... I'm not sure if it ever quite made it all the way back to the faster connections we used to have, or did I just get accustomed to it.
What are the general opinions out there?
~Jim~ Nuvi-660, & Nuvi-680