GPS devices... Where do they get their data?

[dsheely]

I understand Skycaddie advertises they use people on the ground mapping the courses. Is that true for all of their courses? What about the rest of the companies? Garmin is the supposed to be the best GPS company out there but how do they map their courses? Satellite imagery? And what about the smartphone apps... I'd assume they all use satellite imagery which explains alot, since I've tried them all, Skydroid, golfshot, swing by swing, and on and on.... they're all off on several holes at every courses. Sometimes by as much as 20 yards. If I can't trust GPS for every shot over 50 yards, what's the point of having one? Course knowledge doesn't cut it.

[Hacker#5252]

Well Skycaddie hires humans to do the job, others do not I would guess, since it's skycaddie's main selling argument. I think that's true for most of their courses (read close to 100%). Every course in my area has been mapped by a human, in any case.

I've had mine for one summer only but I've compared it with a Bushnell Tour V2 and the distances on sprinklers and my gps was bang on every time.

Also, gps chips in phones aren't as good as the ones in golf gps, or so I've read and heard. It makes sense since it doesn'T really matter if our car gps is off by a few meters, but it's another story with golf.

I chose gps over laser because I wanted obstacles I couldn't see and didn't mind the annual subscription. Downloads are a non-issue for me, all the courses I'll ever need have been downloaded already: I'm good to go.

[avgjoe]

I recall someone said he did mapping, cant recall what thread... my guess is satellite imagery, and most all use the same mapping

[DaveLeeNC]

Most golf GPS devices use satellite based mapping services. Using this technology for a variety of purposes is becoming very common. For example, I am n the process of having a new roof put on my house. The roofer (and insurance company - it is a weather damage issue) is using 'Eagle Eye' for the measurements, rather than doing it manually on-site.

dave

ps. These mappings will occasionally generate huge errors (occasionally)

[phil75070]

SkyGolf was the first out with a golf GPS and satellite imagery then wasn't what it is today. I think had they to do it all over again they, too, would use satellite imagery but are kind of stuck because of the extensive advertising that claims walking the course is such a big advantage. Granted, the equipment they use for measuring is of a much higher grade but itself is GPS technology and the accuracy will also be determined by how attentive and precise the guy doing the walking of the course is.

It is much quicker and easier to change maps using aerial / satellite imagery. I had a Sky Caddie during a time when the course redid our greens, not only enlarging them but actually changing the shape of a few of them. It took three years for SkyGolf to catch up with those changes.

[Wayneo]

AvgJoe, The user was Rich7, he made a total of 6 posts, all in this thread. Mapping technique started at post 49. Then he disappeared.

http://www.golfwrx.com/forums/topic/511834-sgx-wins-golf-digest-gold/

[Jacoby]

I am pretty sure Bushnell gets their GPS data from iGolf. From what I remember, if you have a Bushnell GPS device (Neo+) you have to register with iGolf for updates and such.

[DaveLeeNC]

[quote name='Jacoby' timestamp='1347145720' post='5608851']
I am pretty sure Bushnell gets their GPS data from iGolf. From what I remember, if you have a Bushnell GPS device (Neo+) you have to register with iGolf for updates and such.
[/quote]

That is the case.

dave

[Mystic Elder]

I'm not sure of all the companies but I know that Skycaddie, Golfbuddy and Golflogix have walked courses at some point. I'm not saying all courses but I have ran into reps from all three. It may be nitpicking but Skycaddie claims to have walked all courses with professionals with "survey grade" GPS. That isn't the case because some courses have been mapped by customers with more rudimentary points. If you go to their website you can look at their course list and any course with one icon has not been mapped "professionally". I do have to wonder what "survey grade " is. As far as I know they are still subject to GPS inaccuracies such as ionosphere. 1-5 yards variable.

As far as mapping with imagery, you need to be aware that there are huge variations in the accuracy based on the WPTS they are using. You can't assume that these companies are using the same resources. Any satellite and aerial pictures have different standards of accuracy, there is sub 20 meter , sub 1.85 meter and < 0.5 meter with different resolution levels. Basically you get what you pay for. You read a bunch of posts saying they all use Google or Bing...some do some don't. Just because you see Google imagery does not mean the course was mapped with it. Again, it all depends on the level of georeferencing and sub meter accuracy they are paying for.

I would suggest that any company grabbing co-ordinates from Google Earth because it's free and not going to source ( satellite imagery provider, Google does not own satellites) are going to have less than accurate readings. I will say one thing....to the original thread starter, if you have tried a bunch of these apps and you are getting the same bad results I would look at your GPS chip being more of the problem. I doubt they are all mapping the same way.

[Mystic Elder]

[quote name='phil75070' timestamp='1347145069' post='5608813']
SkyGolf was the first out with a golf GPS and satellite imagery then wasn't what it is today. I think had they to do it all over again they, too, would use satellite imagery but are kind of stuck because of the extensive advertising that claims walking the course is such a big advantage. Granted, the equipment they use for measuring is of a much higher grade but itself is GPS technology and the accuracy will also be determined by how attentive and precise the guy doing the walking of the course is.

It is much quicker and easier to change maps using aerial / satellite imagery. I had a Sky Caddie during a time when the course redid our greens, not only enlarging them but actually changing the shape of a few of them. It took three years for SkyGolf to catch up with those changes.
[/quote]

I'm not sure what the wait time is for Skycaddie to come to a course and remap changes. I guess it depends on if they still have reps on the payroll in the general area. The problem with satellite imagery is that it may take a year or longer before the imagery database the company in question is using updates. Generally, imagery gets updated more frequently in areas with more urban developmnent since a lot of demand for imagery is based on civil engineering projects. Again....if the company uses multiple resources for imagery the chances are the quicker they can make the changes. They could also just pay about $3000 to the imagery provider to task the satellite to take a new picture. One advantages of imagery is that new courses can be mapped months before they are open.

[BlackDiamondPar5]

[quote name='Mystic Elder' timestamp='1347189709' post='5610765']
[quote name='phil75070' timestamp='1347145069' post='5608813']
SkyGolf was the first out with a golf GPS and satellite imagery then wasn't what it is today. I think had they to do it all over again they, too, would use satellite imagery but are kind of stuck because of the extensive advertising that claims walking the course is such a big advantage. Granted, the equipment they use for measuring is of a much higher grade but itself is GPS technology and the accuracy will also be determined by how attentive and precise the guy doing the walking of the course is.

It is much quicker and easier to change maps using aerial / satellite imagery. I had a Sky Caddie during a time when the course redid our greens, not only enlarging them but actually changing the shape of a few of them. It took three years for SkyGolf to catch up with those changes.
[/quote]

I'm not sure what the wait time is for Skycaddie to come to a course and remap changes. I guess it depends on if they still have reps on the payroll in the general area. The problem with satellite imagery is that it may take a year or longer before the imagery database the company in question is using updates. Generally, imagery gets updated more frequently in areas with more urban developmnent since a lot of demand for imagery is based on civil engineering projects. Again....if the company uses multiple resources for imagery the chances are the quicker they can make the changes. They could also just pay about $3000 to the imagery provider to task the satellite to take a new picture. One advantages of imagery is that new courses can be mapped months before they are open.
[/quote]

My experience is those using aerial imaging can respond much faster to course changes/additions. In the last couple of years I played a couple courses that were brand new (the same year I played them), and they were already mapped even though Google Earth showed bare land and SG hadn't added them to their map DB yet.

It seems a company like Garmin, that does updates every quarter, has the resources to have fresh maps at relatively frequent intervals.

To the OP, your issues with your phone app accuracy may be two issues. One the device itself may not have the best GPS chipset, Two, course mapping error. I can tell you the good news is with Skydroid that you can go to their website via your computer and you can map or remap a course for yourself. You might want to try this. Also the advantage is that you can add more hazard details if you wish. However if they don't have a very detailed aerial picture of your course your going to be limited in how accurate you can be.

[Mystic Elder]

Well the OP mentioned Skydroid, Swing By Swing and Golfshot. I believe the first two are based on Google, Golfshot is based on Google or Bing. The first two have customers mapping their own courses although SwingByswing will do it for you if you pay a fee. Golfshot maps them for you.

I just think it unlikely that all 3 apps would have the same errors because 3 different people mapped them. Unless of course all 3 people used Google and Google is not accurate or outdated.I'm leaning more towards the hardware.

I know that Garmin has various different sources going well beyond Bing and Google general access. I also know that Golflogix uses up to 10 different sets of imagery depending on country because I had an e-mail from a person when I had a question. That's why they have courses mapped that others don't but they do not show imagery on some courses even though they are mapped."sorry we can't show you our imagery".