PoI Accuracy

i agree. download a file foe hardware stores. 1 store was in a forest the other must have been on a barge because it was i the middle of a lake. at least, i know there is one in the town just to find it visually. the contributor resides at the other side of the country. if they would check it with the the poi editor they would see that some of entries are a 1 mile or 2 out. they made an effort but it needs to be done precisely to be of any value.

I have observed the same lack of accuracy in some POI files. I assume this occurs when people run a list of street addresses through a geocode application and accept the generated coordinates. The geocoder can be really off and it may be difficult for people to confirm every single location.

I usually run POI files I really need (rest areas, golf courses, casinos ) through Google Earth, just to check. I have seen some really odd locations but most files do not have a singificant number of errors.

Myself I have created two POI files. Several items I know are not exactly accurate. Both took me about two weeks each to try and verify on Google's street view if it was available. Several of them I was able to correct since I was able to see them it street view. Granted the POI file's I created I have not received any correction requests but they are generally used by a select group of individuals. The files are for VFW posts for Georgia and Ohio.

As for descriptions admittedly it is nice but for most files people already know what they are looking for. Now if something is labeled as an attraction, especially an out of the way or odd ball one, a description of where exactly to see it would be nice.

And in reality the ones that come from Garmin or any of the others are not exactly correct either. Bit for those that we, as group, have some control it would be nice to get corrections and they get updated and reposted. There are a few that I have changed or added to myself after downloading for my purposes. I also have updated in the original thread for the POI to hopefully it gets updated. Either way myself I still feel the POI files that here are more accurate then what the manufacture has. Plus if the maps were more accurate as addresses go then POI files would need less work.

the various file formats. I have started building GPX files exclusively for my use and convert some of those to CSV for sharing. The CSV ALWAYS HAS LESS information than the companion GPX because of the file format constraints.

As to location accuracy, there are varying degrees available from the geo-coders. Most of my files are address or street level while others I have loaded from others may be at state, county, city or zip.

I think POI files based on actual visitor or personally being on a location offers much more value then going through a list and just trying to make a large file.

I'm working on a file for RV visitors to Savannah, just got tired of answer the same questions. I could easily just try and look up each location, but I am going to each location and getting the actual coordinates. This way I know my file will be 100% accurate and won't send people on a wild goose chase..

The thing I don't want and which has happened before, was that someone took my information packaged it and sold it, claiming it was there POI.

When you create your CSV / GPX file in Excel, use the password protect feature and then 'brand' it by putting your contact info in it. As well, you can edit the file attributes (before locking) as a secondary measure.

Try creating and keeping the Wal Mart or Best Western Hotel files up to date and accurate by visiting each location personally. Visiting each site maybe fine for your application but in most situations this isn't really practical.

bummer...

It's a given that the whole point of a gps POI is an accurate final destination. However I doubt that most of the file submitters are doing it just to show how prolific they are. Many times it's just as relevant to know if something is in a reasonable radius to where you are, or are going.

In the large American Legion file I submitted for example, it was done because the previous file wasn't complete, it was requested, and I had the time. I did the best I could without personally visiting the 6155 US locations. And, by the Legion's own admission (by phone no less) some of the addresses published were probably in error while other known locations were never even submitted to the headquarters for inclusion in their own list. In short, no it isn't spot-on.

I did the best that was reasonably possible using Google maps & EPE and although I wouldn't guarantee every exact coord pair, I would certainly feel comfortable relying on it to tell me if there was a Legion hall in the town in question.

I'm not in the Legion myself so I'm probably not going to personally verify them, but I AM here & willing to accept your corrections.

And in any event feel free to use the file as a starting point for each of your 6000+ personal location visits.

I think you missed the point. Considering the rate of inaccuracies of the files, then your 6000+ files could have an inaccurate rate of more then half or 3000+ locations not where they say there are or off by miles. What good is the file then?

IT would be a more accurate file if you asked users to submit there Wal-mart locations they actually visited. There is a Wal-mart site out there that does just that.

I have used and discarded one of the Wal-mart files. IT was way too inaccurate. It often put the Wal-mart in the middle of a residential neighborhood and miles away from the actual location or the Wal-mart closed years ago.

Kinda tough if you're following the GPS for Wal-mart towing a huge fifth wheel and you end up in some bad neighbor hood with low hanging trees and no turn arounds, that is EXACTLY what happened to us.

Having a file that is 50-75% inaccurate is pretty useless.

Which is exactly why there are site like this. In hopes of people having the same interest. Instead of creating their own file they can download a created POI, and not take it as gospel, check the sites that they are familiar with and let the maintainer know. Then hopefully the maintainer updates the original file. Heck even Garmin itself is inaccurate also and they have people that get paid to do this stuff.

As mentioned before I did two POI file myself. VFW for GA and Ohio. I know where a few are in both states and know those few are accurate. Using Google Earth I was able to verify several others with street view. Like the American Legion POI mentioned above post's close up for various reason's or move all the time. Several meet in the same post as the American Legion so when you go looking for the VFW you find an American Legion post and think you might be in the wrong spot.

Again it is not reasonable to visit every location out there. For my POI's my goal is to get the state level sites to eventually post my POI's and hopefully the member of the different post's can inform me of the correct sites.

Where are you in Savannah? I live in Pooler myself.

On the contrary, I have experienced very few issues with inaccurate locations in most of the files I get from this site. Those that I have found to be inaccurate, I have reported to the author of the file and have seen corrections made and files re-uploaded. Large POI files take a good amount of time to complete and, like several other comments in this thread, it is unreasonable to expect the author of the file to visit each and every location or to attempt to verify each and every location in any POI file. I appreciate the efforts the folks on this site have gone to to prepare and share these files. I wonder if Creeper has contributed any files to this site. If he has, he should be aware of the difficulties in creating these files and would not be so critical of the efforts of others.

Not really. I get the point.

If any of them actually are off then it's either because the directory is wrong or Google maps is. In either case how would one otherwise ( without a gps) begin to find and travel to the location? And, if a file includes the listed address info and should the coords be inaccurate then the destination can still be found the 'old fashioned way' and then one can submit the corrected coords, yes? If the address info is wrong, then you can shoot the messenger if you like, but at least it's a portable, targeted, address book that's as accurate as the source.

I also find it hard to believe that 50% of the POI's on this site are inaccurate enough to be useless. And that has not been my experience.

Consider my other point, though.

If you rode a Harley, you'd appreciate the accuracy of the H-D Dealers POIs I created and maintain. I've verified the accuracy of each POI in Google Earth where possible. I've personally visited around 100 of the 941 locations. I've received feedback from many other riders commenting on corrections, additions and deletions, researched same and accepted most of them. In order to properly alert POIs, they must be less than 50 feet from the nearest street on the Garmin maps, so I adjust locations to be that close, even if a location is further from the street. I've spend close to 600 hours on this POI file over the past 3 years.

I've also created an 8437 POI National Parks POI file from an Excel file I received from an NPS ranger. While I've done what I can, I've looked at locations and some are off far enough that you couldn't use a picnic table that's in the ocean where the coordinates point. But it's a good start. We are a community and the POI information is only as good as the feedback we get. To date, I've received two comments on this NPS file, one asking for full park names on all POIs which I did in about 40 hours of work. Garmin sells 3 maps for the NPS, East, Central and West at $116.65 each. I wonder if their POIs are more accurate?

I ride a full bagger and I DO appreciate the H-D file.

And even if it wasn't accurate to the door, I find it valuable to at least know what direction to travel toward if & when I need to find a dealer away from home.

..If only to get the mandatory t-shirt.

I must say that everytime I have found a discrepancy in one of the files and I have reported it to the maintainer, it is usually fixed within a couple of days. In some instances, in a little as half an hour. You must give these folks some credit in that they have an immense task in front of them and that task is taking information from other sources (given, some of that information is incorrect) and creating a file for something they have never seen. For instance, I recently found a McDonald's where the location was off by 250' or so. This was the location provided by the McDonalds's Corp., but it was inaccurate. The file was changed within one hour after notifying Mahoney. The simple solution is this: when you are out and about and you notice a discrepancy in a location, make a note and notify the maintainer of the file when you return home. In that way, everyone benefits. (By the way, to all of the maintainers that I have contacted over the last few months I would like to say Thank You for a job well done.)

with files I've found here. I don't expect front door accuracy because then you might not even be alerted to the location. For instance a store in a mall might require a location at a mall entrance rather than the store door. I guess it comes down to the fact that if these aren't accurate enough, don't use them, find some other way of finding places. If they work for you, then use them as most of us do. Personally, I like the POI's here and use them all the time and appreciate the hard work people do in making them and posting them here. Don't be concerned if a few locations aren't 100% accurate, I'll bet I can find them close.

I have had a few problems with files but for the most part, the authors have corrected them in little time. I am wondering however, if everyone knows the difference between:

Decimal Degrees
Decimal, Minutes, Seconds
GPS Coordinates

The reason I bring this up is you could put in the wrong format into the file and this could put you way off. I believe there have been posts on how to do this or how to convert.

But I use itouchmap.com/latlong.html It not only does the conversion but displays the point on a map or sat view.

It would be much more beneficiary to everybody if we spent our energy in helping make those files more accurate instead of complaining.

I agree fully. It is hard to provicd 100% accuracy on a large file, when it covers a wide area. Also the company websites are not always right with their addresses either.

Let's face it. Unless you, or someone, has physically gone to the spot and recorded it with an accurate gps, you will never get good coordinates. Most times you know the address and then reverse geocode.
As we all know, reverse geocoding relies on many false assumptions, so it's not surprising that the resulting coordinates are inaccurate.
Put up with it, you are close enough to look around or perhaps even ask.

but with the improving google/bing aerial, street level and birds eye views, it is getting easier to verify locations without going there.

I use satellite view of any maps, so that I can actually see the building, whenever possible. Even this is not perfect, but if it's a car dealership and it looks like a car dealership, the odds are pretty good.

Sometimes place is somewhere Google Earth didn't use a lot of resolution and then I will go to the company's website and see if they include a map. I will use their own map, where possible, but a lot of companies do a lousy job of mapping their locations. If it's truly uncertain, I just don't include them.

I'm afraid that a lot of people simply geocode them and don't cross check the results. In some cases the geocoding only gives city accuracy and these people don't bother looking deeper.

"You must give these folks some credit in that they have an immense task in front of them and that task is taking information from other sources (given, some of that information is incorrect) and creating a file for something they have never seen"
Well said. The people working on all these POI files get paid how much for their work? If you want a 100% accurate file you should pay for it on a per loaction basis or go make your own.
It's really laughable that anyone would expect someone to personally visit every Walmart,McDonalds or other business in the USA and Canada to record their exact locations at their own expense and then give the information away for free.
Maybe I'm off base but you pay nothing for these files, people that maintain them do the best they can and fix errors when pointed out on top of everything else going on in their lives but unfortunately some aren't satisfied and have to complain about something they paid nothing for and put forth no effort to maintain or fix.
And is anyone really focused on the size of their file???

Compare what you get from Navteq / Garmin built-in pois and user maintained POIs. It takes Navteq / Garmin 2 - 3 years to correct reported errors in the built-in POIs. And it takes days for the user maintained POIs. POI Mainteners do the best they can and nobody is forced to use the POIs found here.

You are correct in that a file is only valuable if its useful. Its commendable, and I believe critical that people who find inaccuracies send those corrections to the file creator. Though I make every effort to verify location on files I've created, I welcome corrections and additions from other members.

However, expectations of "perfect" accuracy from a free site is simply not realistic. Even the POIs provided by GPS manufacturers are not very accurate (I can't tell you how many times I've been taken to an empty field or a forest), so how can hobbiests be expected to be 100% accurate? Or even 80%?

My point is that we all need each other to make this work. I view POI Factory as filling the gap left by the manufacturers. Complaining about problems won't make it better. And certainly "leaving the site" because of inaccuracies won't either.

An excellent example of this is the rest area file. While a few individuals have maintained the file, it has become what it is due to the contributions of many people. If all we did was complained about the issues with the file, then not only would it be a very inaccurate file, but the maintainers probably would have lost interest long ago.

I don't expect a lot of accuracy from a user supported site, general ballpark is good, most places have big signs to show where they are. I tried to find a Hastings book store using the Garmin POI, it sent me out to the middle of nowhere.

Best Western has a CSV file on their site for the locations of all their hotels/Motels

I maintain Wal-Marts. I use Google Earth, Trailer-Life RV CD and just tried itouchmsp.com

Different answers for each. I prefer Google Earth and use points from the front door of the building or at least the middle of the parking lot. Wal_Marts normally take up a block or 2 so street address is very in-accurate.

I also so decimal degrees, ie: 35 deg, 30 min 20 sec is 35.5055555

With all that said, a Wal-Mart in Stilwell, OK has an address of Route 6, Box 1895 (Wal-Mart web site). Any suggestions?

Bing Maps lists as RR6 Box 1895 Stillwell OK 918-696-3141 AS A Super Walmart.-94.65494,35.815046 I tried Google Maps,Google Earth and Bing Maps to zoom in but don't see anything.Is this a new opening by chance?Bing does list it.

I used the Walmart web site and zoomed in on the store location and got a few intersecting street names. Then went to Google Earth and located what I think will be one of the main entrances to the new store. Its about 1100 feet west of Rte 59 just past 3rd Street on W. Locust Street. The Store appears to be under construction on Google Earth and would be on the south side of the street. Remember, this location can only be accurate if the info Walmart supplied is accurate on their website.
I see Charles also gave info too. He's probably right:))

My best guess on the co ordinance:

-94.631231 35.808472
Hope this helps you.

How about a new file with only actual visitation coordinates?

This would be nice but the logistical problems would make it impossible.
1.Suppose there are only a few sites, example US National Parks. Each park would have to be visited by someone. That person reports the coordinates and address. To whom and how?
The recipient of the data would then have to correlate and verify the various data. What does this poor person do when the data differs? I guarantee that not everyone will report the same co-ordinates and address for each park.
Having done this work it must be maintained. This is a lot of work for an unpaid volunteer.

2. Now imagine the increased magnitude of work if the POI listing was for all McDonalds. Impossible? No. But improbable, yes.

Wal-Mart #81 Stilwell Route 6 Box 1895 Stilwell OK 74960 (918) 869-3141 Store # 81 -94.631078 35.807614

After re-checking Google I agree that these are the best coordinates. Your heading says Wal-Mart Corporate, do you have access to all GPS listings. I use walmart.com but can only get address, phone #'s etc.

One of my contacts receives the file directly from Wal-Mart on a monthly basis. I turn it into a GPX for him and send it back, so yes the file is directly from WM HQ.

It some times lags the info you have as it may take a couple of cycles to list new locations or remove closed stores.

If it's for public use could you forward me a copy in GPX or CSV so I can check coordinates.

Thank-you

Dear Daniel,

I agree with you and used the same approach with the HESS file. One should always take a look at the satellite picture to place the coordinates.

david

Visual confirmation would increase the accuracy of the file.

A better way to do it would be to ask people to submit things in their own area they verified. Would be more time consuming, but far more accurate.

A LONG time ago I submitted a correction to one of the truck stop files. The posted file had the truck stop in the middle of a marsh miles away form the actual location. The listed coordinates were not the ones listed on the truck stop website. The last time I checked it still listed the truck stop in the Marsh.

Now during these past holidays we had to drive up the east coast and we looked up 30 locations we wanted to see. Out of the 30 only two were accurate. Only ONE provided an address, which was an old building in the middle of a corn field. One was found by mistake only after we gave up looking for it in the listed location and it was a good distance aways. We don't expect front door directions and will go 1 mile in each direction in attempt to find the location, but when you're in the middle of a corn field with nothing but corn for miles, it's easy to assume it's not accurate.

I have submitted NUMEROUS corrections to file posters and not one response. But, why use files if I have to submit hundreds of corrections?

It seems using a Geocoder is a real problem.

The only file i found REALLY accurate was the rest stop file and cudos to that poster.

A comment from Creeper

I have submitted NUMEROUS corrections to file posters and not one response. But, why use files if I have to submit hundreds of corrections?

It seems using a Geocoder is a real problem.

If you doj't get a response send them to Miss POI. Alot of people create a poi to post so they can get the redlight and speedcamera file then leave or just to get the badges. Over 200,000 listed now and olny maybe 50 to 100 may post in any one month is my guess.

Even the POI’s that come with the Garmin units are not always accurate. In my area, a suburb, the map on my Nuvi shows businesses on streets that are just regular developments, not business areas. Turns out that these are the home addresses used to register a business. Good luck if you were looking for a nearby towing company; it is actually many miles away.
To be fair, Garmin can only use the information that they are given and could not possibly follow up on every entry that they make but they should act in a timely manner when the mistakes are pointed out to them. The same goes for any POI lists that are provided on this site. If you know you are going to a certain area and want to find a particular place that is in one of the members POI files, have a check in Google earth beforehand and verify that the point is in fact a valid entry.
So for now, all we can do is send those error reports to Garmin or in this sites case, the author of the list or Miss POI.

The last post of creeper does make a good point (hundreds of correction submissions- although I'm not sure I'd blame ALL geocoding services, necessarily), but so does bpaine & johnm405 in regard to letting Miss POI know.

This might be a solution that would cause Miss POI some moderation headaches, but if each poi file page allowed 'corrections' comments then maybe if the original submitter isn't around anymore or unresponsive at least the interested downloaders would know and/or have info to correct their file with.

..Which also brings up the thought that anyone can make corrections to their local file and send it to at least Miss POI, which would help her if she has to do it herself?

JD4X4 has made a good suggestion. If you find a POI file that you are interested in, why not help out the original author and check a few of the locations in your area. If you find any errors send them in, isn’t that why we joined this site, to help fellow GPS user’s out?

That would be fine if there weren't so many corrections needed. Why have a file posted if it is riddled with errors? Users should submit the problems and if the file is riddle with errors it should be removed until the author decides to fix it.

Tried another campground file and looked up a local VERY WELL known campground that has been there for years, has the GPS coordinates listed on their website, yet the file put the campground 10 MILES from it's actual location.

I also went back to see if one of the previously mention points was still there or we missed. We looked for miles in the general area. The POI file directed us to get off the exit, turn right, travel about 5 miles and put the POI at an intersection. What we should have done was use the same exit turn left, go 1.5 miles, turn left again and go .5 miles. So the POI file was off by 7 miles.

Like I have said before I have submitted dozens of errors and have yet to receive a single response. Seems these files may have become orphaned. Now between going to a non existent POI and submitting corrections is a big waste of time.

What I find interesting is there are many people out there selling POI files and they contain the SAME EXACT errors as some of these POI files. So it appears they are lifting the files and selling them, not realizing how inaccurate they are.

You were gone for about 19 months before you returned 3 weeks ago with your complaint. When did you submit corrections?

What do mean not forced?
a_user told me if I didn't use the rest area file he would shake his stick at me and turn me in to frog.

And actually the combined file is probably one of the most accurate files. you get right to them but the problem is lots of them are closed do to budget crunch. but coordinates are accurate.

Don't talk about rest areas and guys shaking their stick at you in the same sentence

Creeper said in part..

Seeing you're complaining about accuracy, shouldn't the word "THERE", as used in your above sentence, be spelled "THEIR" After all, we do want to be accurate.. don't we?

Nuvi1300WTGPS

Nuvi1300WTGPS@Gmail.com

Actually I turn it into a baseball bat and beat people soundly about the head and shoulders after whacking the side of the knee.