- aston-hill-trig-WGS84-location.PNG (123.36 KiB) Viewed 640 times
How do people use a GPS and get accurate enough coords to be able to dig up a buried block - given that GPS are supposedly not pinpoint accurate?
WGS84 location data dfferences
WGS84 location data dfferences
I've just noticed that the WGS84 N & W coordinates are different on the new app and on streepmap.co.uk? See attached.
Is the app correct, as I've been trying to enter the coordinates into a Garmin etrex 32X and they are way out - from streetmap.co.uk?
How do people use a GPS and get accurate enough coords to be able to dig up a buried block - given that GPS are supposedly not pinpoint accurate?
Is the app correct, as I've been trying to enter the coordinates into a Garmin etrex 32X and they are way out - from streetmap.co.uk?
How do people use a GPS and get accurate enough coords to be able to dig up a buried block - given that GPS are supposedly not pinpoint accurate?
Re: WGS84 location data dfferences
I'm in the middle of a clean-up exercise of the TUK location data. Things are getting gradually better, but there may still be inconsistencies. The data shown on the website is usually of better quality than the android app, as that's much easier for me to update.
I've had a look at the various coordinates for Aston Hill, and here's what I found...
* Gridref displayed on TUK website - accurate to 1m
* WGS coordinates on TUK website - accurate to 1cm
* Gridref displayed on Android app: INACCURATE by 2m
* WGS coordinates on Android app: accurate to 1m
* Link from TUK website to Streetmap: INACCURATE by 2m
* Streetmap website's coordinate conversion page: INACCURATE by 1.6m
So, the core geodesy of the TUK website is demonstrably more accurate than that of the streetmap website. However the bugginess of what gets displayed to the users, and linking to consumer websites, is worse on TUK than it is on streetmap. Which does kinda fit with the geek's hobby vs consumer product nature of the two websites
I've added a ticket to the issue list to fix both the T:UK issues.
NB, none of the above are "way out". Eg "N52 45.326" corresponds to 52.755433 whereas streetmap has it as 52.755435, so a couple of metres difference, reflecting the slight error in TUK's streetmap link. You sure you're not misreading a ':' as a '.' ???
I've had a look at the various coordinates for Aston Hill, and here's what I found...
* Gridref displayed on TUK website - accurate to 1m
* WGS coordinates on TUK website - accurate to 1cm
* Gridref displayed on Android app: INACCURATE by 2m
* WGS coordinates on Android app: accurate to 1m
* Link from TUK website to Streetmap: INACCURATE by 2m
* Streetmap website's coordinate conversion page: INACCURATE by 1.6m
So, the core geodesy of the TUK website is demonstrably more accurate than that of the streetmap website. However the bugginess of what gets displayed to the users, and linking to consumer websites, is worse on TUK than it is on streetmap. Which does kinda fit with the geek's hobby vs consumer product nature of the two websites
I've added a ticket to the issue list to fix both the T:UK issues.
NB, none of the above are "way out". Eg "N52 45.326" corresponds to 52.755433 whereas streetmap has it as 52.755435, so a couple of metres difference, reflecting the slight error in TUK's streetmap link. You sure you're not misreading a ':' as a '.' ???
Re: WGS84 location data dfferences
appreciate the detailed reply. I was not trying to be pedantic, only trying to understand how people could be locating (and unearthing) buried blocks with pinpont accuracy. Ironically, since using the coordinates on the app, and also calibrating handheld GPS compass- I tested 3 WGs84 coordinates, and they were accurate. I think I also need to learn how to use my Garmin etrex 32x correctly; as well 
. Thanks for the reply.
. Thanks for the reply.