How reliable (percentage wise) are these POI's?

I think that most of the files are accurate. But it all depends on who made the files. Some members are more particular about checking for errors than others. The other problem is (especially with nation-wide lists) that you may be making locations you are not familiar with. That is why it is so important to report errors. Stores close, move and open. It all depends on the database you use to make the files, and how well that store keeps them. I have had to use local phone books, websites and physical verification for some files.

I try and check files from this site for my local area and state that I travel in. I would guess that most files from this site are 95% accurate or better for the files I have used. The most common error is it is maybe off a block or so.

Daniel

Errors do happen but as with any business, things change, move, close etc. It wasn't the case in this instance but does happpen. Please let the maintainer of the file know the location in question so that they may make the corrections so that the file can help others. Only thru this approach can we ever truly approach 100% error-free.

I have found other errors in this poi, If you can give me the city/state or store number I will look into it...

This is one way to make these pois better, the community reporting errors and having them corrected..

They are only as accurate as the person that is creating the file makes them.

could you send me the address of the campground so that i may add it to my POI list I DONT THINK I HAVE that one!! thanks

The only one that appears it may be incorrect is:

Wal-Mart Store #2222
333 Main Street
Tewksbury, MA 01876
(978) 851-6265
Coordinates -71.262359 42.621365

Is this the store? The coordinates appear to be close/correct according to the Wal-Mart store finder and GPS Visualizer, but I do not see a store using google earth....

Help from the community? Is there a store in Tewksbury?

The Geocoding utility plays a big factor in getting the correct coordinates. When using the default 'Yahoo' source with http://www.gpsvisualizer.com/ (and I assume others are similar), it will show the "Result precision" when geocoding individual addresses. If it can't find the address, it will give the street coordinates; if it can't find the street, it will give the city or zip coordinates; and this continues on through State, Country, etc.

When batch geocoding, it doesn't display the "Result precision"; so what you think are the coordinates for a specific address could be the coordinates for the street, city, or state. That may be what happened when he ended up in a residential area ... it calculated the street or city coordinates. This will happen often when the address is new.

Sometimes the author leaves out the "-" for the longitude; other times the long/lat are swapped. Or the same coordinate is in both the long and lat field. This is easily checked with a POI utility, be it 'POI Verifier II' or some other. It would alleviate a lot of headaches if the author would check their files before posting.

RT

...including the one that comes with your GPS. Mine has had a few, including one that was off by 9 miles, the difference being between at the top of a mountain vs. its bottom with lots of slow, winding roads in between.

For critical destinations where I'm traveling hundreds of miles, I try to find, prior to leaving on the trip, the location on a geocoder site that shows satellite/map overlays, or on my Garmin topo maps for campgrounds and parks. Call it paranoid, but I like to trust myself the most for something that's important, namely not getting lost and frustrated in getting to an important destination.

I've made a number of files for this site. I've gotten a rare correction from people, one most recently that I had coded on site (a trail head in the Smokies). So, I probably either reversed some numbers on the site, or when I was typing it in to upload to this site.

My other advice to you is to look at the file in advance in something like Excel. I downloaded one file from this site that I was going to use in my home state, and noticed that a whole lot of POI's all had the identical longitude or latitude even though I knew they were separated geographically by as much as 500 miles. So, you can spot some really doozies on occasion just by eyeballing them.

GC

May be a good idea in theory; but in practicality I don't know anybody who wants to eyeball 41804 lines of POIs (zipcodes_V.csv). Programs like 'POI Verifier II' will find the errors you mentioned in seconds, without having to eyeball 41000 lines of data.

RT

work on Macs? I've given up on Windows for my home computer.

I hadn't thought of 41K line files, because all of the files I have downloaded number about 10,000 lines. And most of those are red light cameras in states I never travel to, so I should probably thin those out as well. I should appreciate that others are less frugal in their downloading habits than me.

GC

As a community, We should all take responsibility for correcting errors and not blaming the author.

We want to encourage more people to create/edit poi files as necessary. Accuracy will improve if the community does their part.

I appreciate everyone contribution and when problems
occurs I feel we all should do all part to fix them

Just my 2 cents.

Dear DR,

When the POI is the sort of structure that can be identified from Google Earth, the POI file creator should be encouraged to use the photograph and not rely on a batch decoder for addresses.

david

We shouldn't have to blame the author. The author should accept that responsibility on their own. They should do the best job possible, be it with POI checking software or eyeballing the smaller files before posting. To do a batch geocoding and throw it up on the website without checking it does no one any good. Many times "Bad data is worse than no data at all"!

RT

Ya there is a Walmart store there. Main street is Route 38. The coordinates you give above put the store a bit too far south. If you use these coordinates instead...

latitude: 42.62370111148813
longitude: -71.26564174890518

that will put you right at the entrance on Main street. The large parking lot and building should then be seen to the left (I am using Google Maps, not Earth, by the way).

Cheers,
PT

should we suggest a rating system for file confidence?

As the maintainer (not creator) or several large pois, let me assure you that Google earth or similar satellite photograph providers, (I think that is what you mean by photograph) is not a cure all. The satellite photographs may not be anymore up-to-date than maps supplied by Navteq. The photos like a geodecoder are a useful tool but at times you must rely on the geodecoder which as we know can lead to erroneous information, particularly if it is used in a batch mode. I found another useful tool, GeePeeEx editor for removing/checking errors that may or have been created by a batch geodecoder, using a store locator if available, can be useful, it may show street locations, but their again it’s not always accurate even though it’s guiding potential customers to their location. The most accurate way would be to make a phone call to the location, but I’m not about to call 5000 Wal-Marts to see if their store info is correct. The best is to use all of the tools that are available and hope for the best and help from our growing community…..

Nah! Let's just try and make an effort of submitting corrections back to the original author of the POI file. Perhaps rather than a rating system, instead have a reporting system that shows up on the same screen as the POI. So anyone who goes to that POI file here on the factory sees all reported corrections. When the author corrects any of them, (s)he can then mark the report as fixed and it will be hidden from view, removed, etc.

This will allow people to easily see which files need a lot of work, encourage reporting back issues, and have a central place for the author to see what needs to be worked on. POI files that reach a certain number of reported errors could be flagged to Miss POI to find out if the author is still around, fix them herself, or find a new volunteer to maintain the POI file.

Cheers,
PT

I try and look at the satelite image and make sure that the coordinates are close to an area that they should be. If I was making a walmart file or truckstop and the coordinates showed a residental area, then I would need to get more info and refine it. You can't always tell in a commercial district what stores are where, but normally you should get close enough for someone to find where they are going. I then if traveling in the area will double check with my GPS if time allows.

In a file with 5000 lines it is impossible to do this by your self. That is why I try and help the creators by sending corrections for my local area. But even with the few errors I find, the file is still worth the download and better than the map poi's most of the time.

Daniel

I knew someone would come though. This is a perfect example of the store locator and the geodecoder being incorrect. Even though the store is visible using satellite photographs so are other stores, there is no way to know with certainty which is the store you are looking for, plus a new one could have been built at the location shown by the store locator).

I will update the coordinates today, and once again thank you...

What i like to do when i make a poi is get the address from the website (if there is one) and then compare them with the ones that google earth pulls up, I have seen that if there is only one place listed on the website and google earth will pull up 10 by that name,and i take the time to sort thru them and find the one that matches the address from the website,or if i cant find a address i am comfortable with i then use gpsvisualizer. I know it takes more time but that way if feel more comfortable putting a file on the site.

Ultimately, it’s up to us to make sure our data is right. If a file has an error when it’s first published, then it’s up to whomever finds the error to report it to the author.

Personally, I see this as a helpful service provided by fellow GPSr’ers. If I wasn’t concerned about the quality of the work, I wouldn’t publish any POIs. Obviously, I’d like them to be perfect out of the gate, but I’ve been a programmer too long to think that I live in a perfect world! Once published, I welcome any corrections that the community has to make the file better for everyone. If I’m creating a file with locations outside my local region, then I expect the help of others who are in the area to make sure it’s right.

If people are going to complain about free files, created by the hard work of volunteers, well, I don’t have anything nice to say about that.

I still haven’t located the Wal-Mart located in the poi that is in a residential area.... I received an email from tinstaafl, the campground evidently is located at or near Sudbury MA at N42.42646, W71.42424

Edit: The 'for wereskine' is where the campground is located not where the WalMart in the residintial area is....

I've said it before - when we download free POI files we should think of ourselves as beta testers. The files are a work in progress and most always will be. That's just the nature of things.

So when you download a big file do the author the favor of checking your local locations when you have a chance. When you do find an error, report it. This way things will get fixed and we can work the 'bugs' out of the files.

Well Sudbury and Bedford are far enough apart not to get them confused. Perhaps if we knew which camp ground, perhaps the Air Force Family Camp in Bedford?

Bedford is actually almost central to an area around here that is Wal-Mart-free (as hard to believe such a thing exists).

PT

Powder Mill Road and Powers Road, I set my location on my 760 to the coordinates given and the nearest WalMart was about 10 miles away and not located in a residential area. The only thing I can think of is that possibly and older WalMart poi was being used and it had already been corrected...

It happened to me. That is why at least if on the POI we have a notation that the location was verified with date. This way if you are trying to check a POI and it does not have that notation you need to call/verify before you go or try to go there at you own risk then if you did not find it, you can report it to the owner.

You are still taking someones word for it, and I have found that corrections sent to me are not always correct. The problem will still exist if you peronally can't verify it. Plus it's enough work just trying to keep the files up-to-date, correcting addresses, adding phone numbers etc without adding update info which is contained to some extent in the pois listing and the poi posts.

In the future I will always add the locations that have been corected....

Ya, Powder Mill Rd and Powers Road are not in Bedford at all. Right in between Sudbury and Concord so in one or the other.

Closest WalMart to that area would probably be the Chelmsford location, which as you noted, is not that close by. With the way roads are around here, that would be a good 25-30 minute ride.

Or South to the Framingham location, but that area is a huge PITA to drive around as Rt. 9 is a divided road to you often have to go far north or south just to turn around for the store on the other side.

PT

p.s. and both those locations are very much NOT residential.

I can tell you that the red light camera POI is very accurate for the ones I have encountered.

I know the Sam's Club I frequent is off by about 300 yards and is on the opposite side of the road.

I keep meaning to get the coordinates when I go there to email to the maintainer, but I always forget.

I'll see if I can fix it....

I was only talking about the things you really verified. That is why who ever owns the POI you really have to verify any correction, changes. If you are not really sure you don't have to put the notation. If you are sure then you can put your notation. Anyway you are correcting it base from somebody and this is the right time to make sure that the location is correct.

Poll - 86.32% +/- 2.27%

UPDATED POLL 9/17/2008 9:am EDT

Jarvis POLL 89.67%

Sparky POLL 91.41%

Henry POLL 90.81%

These are all +/_ 2.27%

It is impossible to verify a stores location unless you actually visit the location; otherwise you are taking another person’s word that the store actually exists. I took over the Wal-Mart poi for miss poi. Since taking it over I have discovered many apparent errors and actual errors. When or if I make corrections it is with the help of the community and all of the other tools I have access to. This a.m. I started checking locations that may be incorrect using one of these tools. (GeePeeEx editor) The first three I checked were incorrectly named; Wal-Mart Supercenters were named Sam’s Club. The locations of these three were checked using Google Earth and the store locator maps. The process took 15 to 20 minutes for each. With all of that effort, I still would not bet that a Wal-Mart is actually at any of these three locations. The only way that can happen and then it would still involve trusting someone, is for a member of this site to tell me that it is there. As I stated previously the date and contributor of the updates are listed at the download page. I suppose those could be counted as verified but it is a very small number of the total number of locations, less than 2% of the locations that could be counted as verified and I know several of those were found via gps visualizer so… are they verified? I personally would be able to verify two Wal-Marts, the only two I have visited, one in Panorama City, California the other is in Chadron Nebraska. (I just checked the Chadron location and it was incorrect, on the wrong side of the street)

For just Walmart alone, I can think of three (one in Wisconsin, One near home in the Chicago Metro area, and one in Ohio) that have closed down in the past several months, and a new one popped up either a block away, or on the other end of town.

I like the idea of just having each other nicely correct the location, or send in updates when the business has moved to a new location.

I've seen my share of web sites and forums that utilize a "rating" system. They can become a blood bath, and all of a sudden, a lot of the posters that submit entries will stop sending in anything. And the attitude of some of those sites seems to be that "our members are above this and it won't happen" but - it does... I know the basic premise is that only quality posts will be submitted, but it can easily backfire if not handled with care.

As for the Walmart SuperCenter being where the list shows a Sam's Club, I've seen that a year or so ago. As Sam's Club and Walmart are owned by the same corporation, I can see that happening more. Same as all the Sears' and K-Mart's that close a store under one name, and re-open a new store in the same location as the other name. I've got one of those (formerly K-Mart, now a Sears - in the same building) a couple miles from home.

If you know the store numbers of the closed stores and location of the new store, I will correct the file.

New to GPS, downloaded many POIs here, found one error in 5-6 POIs, sent a message to the owner, and in nearly every case, the owner responded with an email in less than 24 hours that they would fix the problem and, moreover, 4 POIs were uploaded with the changes in less than 24 hours. That was unbelievable great service from a volunteer! I'm sold and now willing to check for more errors in my local area.

Tim

I'm not asking about the technical details of the file but how do you create a list from an internet store locator? From a store locator, (1) must each store be manually copied into a program such as Google Maps, Google Earth, etc (2) get the coordinates, (3) copy the coordinates into a .csv file, (4) etc?

Is there some way for Google Earth to output a file or must you cut & paste the Longitude and Latitude?

Tim

Check out this page and the links listed;)

http://www.poi-factory.com/node/343

Miss POI

I use:

http://itouchmap.com/latlong.html

Then look for your building, click on it and you have your new coordinates. I like to put the point right where I need to pull in. A lot of pois just get you close or the point may be on the building leaving you to find out how to actually get to your destination. With this website, you can put your point at the driveway which is helpful for shopping centers or large places where you want to be in a specific part of a large area.

I think it is too much to ask for 100% accuracy, or 100% verification, at least on huge files.

All we can do is work together, to eliminate errors one at a time, as they are discovered.

The best thing to do is to get more people involved. Invite your friends and family to join the community, no matter where they are.