GPS Coordinates on the footage

NextBase Tiffany

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#1
Trying to establish what will be the most customer friendly format moving forward.

We can have either Deg, Minutes and Seconds, nice to look at: 1533198535517.png
Degrees and Decimals of Degrees, less nice to look at, but more user friendly to feed directly in to Google maps etc: 1533198580669.png


Ref here.. https://www.gps-coordinates.net/
 

kohakoo

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#2
Hi,

Does that mean to say we will get 3 decimal places for "DMS" and 15 Decimal places for "DD"?

At the moment we have no Decimal places for Seconds.

Thanks
 
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#3
Suppose it depends what most people would want to use the data for. Although I haven't tried them there are online convertors that will convert both ways.
 

Kremmen

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#4
For my purposes I prefer degrees decimal (like the 312 does/did). 6 decimal places would be ideal.

Also I find it easier to put decimal into Google Earth search, as mentioned.

Given that you have both working 312 v 412 is it not possible to have a user toggle ?

I find this 6 digit DD almost perfect:

The N & W is not required as the W for example should be -1, 0, 1, etc
 
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kohakoo

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#7
Accuracy will be the same.
Yes but, "Does that mean to say we will get 3 decimal places for "DMS" and 15 Decimal places for "DD"?" as in my previous post,

OR, will it still show the same on the video footage.
 

M8TJT

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#8
It will make no difference as both readings are the same. Just shown in different ways.

I would suggest that you do a bit of research on the relative measurements.
DDD.DDDD is whole units plus a decimal representation of the fractional part of a degree. DD:MM:SS.SS shows whold degrees and a Sexagesimal representation of the fractional part.
As an example 3.50 degrees is 3 degrees 30 mins. The degrees are split up int mins and secs the same as a clock.
so 11:45 am is exactly the same as 11.75 hours am.

The point that I was making was that although the readings might be either in DD.DDDDD or DD:MM:SS.SS. If one is converted tho the other, the accuracy will be identical.

The other point that I was making that the location accuracy of the GPS device itself is no more than about 10 feet. There is some good reading HERE that might help.
If the basic positional accuracy of the device is 10 feet (on a good day) then there is no point in reporting that accuracy to a resolution of higher than X decimal places
1 degree of latitude = 60 nautical miles.
60 nautical miles = 364567 feet
10 feet as a proportion of 364567 feet = 10/364567 = 0.0000274
So it should be obvious that, to record a GPS position to 15 places of decimals is totally stupid
A latitude to 8 (0.00000001) places of decimals is to within 44 thousandths of an inch. Absolutely ridiculous. And as for 15, both ridiculous and irresponsible.
The above calculation depends on using degrees of latitude, as the distance for one degree of longitude reduces according to the formula d = cos lat x 60. The above are only approximate as well, and would only hold true for a spherical earth.
And that's without bringing into the conversation the GPS Datum 'problem' and basic map accuracy into the conversation.

For a demo of Datum errors have a look at central Beijing HERE It is a Map projection using the Chinese map projection (more info HERE and the projection that Google Maps uses.So how do yo say whether GE or the Chinese projection is correc. Navigate using Chinese maps and you are on the road, navigate using Google maps and you're in the river.
 

kohakoo

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#10
It will make no difference as both readings are the same. Just shown in different ways.

I would suggest that you do a bit of research on the relative measurements.
DDD.DDDD is whole units plus a decimal representation of the fractional part of a degree. DD:MM:SS.SS shows whold degrees and a Sexagesimal representation of the fractional part.
As an example 3.50 degrees is 3 degrees 30 mins. The degrees are split up int mins and secs the same as a clock.
so 11:45 am is exactly the same as 11.75 hours am.

The point that I was making was that although the readings might be either in DD.DDDDD or DD:MM:SS.SS. If one is converted tho the other, the accuracy will be identical.

The other point that I was making that the location accuracy of the GPS device itself is no more than about 10 feet. There is some good reading HERE that might help.
If the basic positional accuracy of the device is 10 feet (on a good day) then there is no point in reporting that accuracy to a resolution of higher than X decimal places
1 degree of latitude = 60 nautical miles.
60 nautical miles = 364567 feet
10 feet as a proportion of 364567 feet = 10/364567 = 0.0000274
So it should be obvious that, to record a GPS position to 15 places of decimals is totally stupid
A latitude to 8 (0.00000001) places of decimals is to within 44 thousandths of an inch. Absolutely ridiculous. And as for 15, both ridiculous and irresponsible.
The above calculation depends on using degrees of latitude, as the distance for one degree of longitude reduces according to the formula d = cos lat x 60. The above are only approximate as well, and would only hold true for a spherical earth.
And that's without bringing into the conversation the GPS Datum 'problem' and basic map accuracy into the conversation.

For a demo of Datum errors have a look at central Beijing HERE It is a Map projection using the Chinese map projection (more info HERE and the projection that Google Maps uses.So how do yo say whether GE or the Chinese projection is correc. Navigate using Chinese maps and you are on the road, navigate using Google maps and you're in the river.
I don't need a lesson. You miss my point, I'm not talking about the difference in the system used, I'm simply asking how many decimal places will be shown on the proposed Dashcam screen whichever system is used.

It WILL make a difference if I take a reading off my dash cam screen ( no decimal places ) and compare it to my GPS reading which is showing decimal places.

If I enter both readings into any good mapping programme , the locations will be different if there are any figures after the decimal point.
 

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#11
Degrees and Decimals of Degrees, less nice to look at, but more user friendly to feed directly in to Google maps etc:
Google Maps uses degrees, minutes and seconds with 1 decimal place as it's main display format, and you can enter the same format directly into Google search:
51°34'18.7"N 3°12'10.3"W

You need a good GPS receiver to be worth entering the decimal place on the seconds, it only affects the result by a few meters, this works too.
51°34'18"N 3°12'10"W

Easier to type this format in from memory too, except for the people who don't know where '°' is on their keyboard!
 

Kremmen

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#12
TBH I find that H:M:S typing in a nightmare.

Does Google Maps work differently from Google Earth as GE accepts DD with ease, just numbers and a dot.

I'll stick with my DD preference :)
 

kohakoo

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#13
Google Maps uses degrees, minutes and seconds with 1 decimal place as it's main display format, and you can enter the same format directly into Google search:
51°34'18.7"N 3°12'10.3"W

You need a good GPS receiver to be worth entering the decimal place on the seconds, it only affects the result by a few meters, this works too.
51°34'18"N 3°12'10"W

Easier to type this format in from memory too, except for the people who don't know where '°' is on their keyboard!
Look at the OP's original images on this subject.

I looked at the images of the proposed system and spotted the decimal places.

I AM talking accuracy!

Your coordinates N51° 34' 18.7" W3° 12' 10.3" . Your coordinates without a decimal place in either N or W is N51° 34' 18" W3° 12' 10".

The distance between is 73ft. If that's close enough for you ( a few meters?).
 

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#14
Look at the OP's original images on this subject.

I looked at the images of the proposed system and spotted the decimal places.

I AM talking accuracy!

Your coordinates N51° 34' 18.7" W3° 12' 10.3" . Your coordinates without a decimal place in either N or W is N51° 34' 18" W3° 12' 10".

The distance between is 73ft. If that's close enough for you ( a few meters?).
No decimal places on the seconds puts it at about the margin of error for a typical dashcam, if you want it more accurate and have a good GPS then use 1 decimal place like Google maps, that gives you 1/600th of a nautical mile accuracy, which is good enough for most people. 3 decimal places like in the OP is pointless!
 

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#15
In poost 5 you were talking about accuracy, which is what I tried to point out.

Three places of decimals on latitude 0° 00′ 0.036″ (three places) gives an accuracy of about 1m to get a similar accuracy (1.113m) you need D.D of 0.00001 (5 places). However that is to an accuracy level that is not supported by the dashcam.
So it would appear that a absolute max of five places D.DDDDD or thre places DMS.S should be applied tho the dashcam readout as any greater accuracy is a waste of time.
 

Nigel

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#16
In poost 5 you were talking about accuracy, which is what I tried to point out.

Three places of decimals on latitude 0° 00′ 0.036″ (three places) gives an accuracy of about 1m to get a similar accuracy (1.113m) you need D.D of 0.00001 (5 places). However that is to an accuracy level that is not supported by the dashcam.
So it would appear that a absolute max of five places D.DDDDD or thre places DMS.S should be applied tho the dashcam readout as any greater accuracy is a waste of time.
Not sure you got that right?

Using the distance calculator at https://www.movable-type.co.uk/scripts/latlong.html ,
the distance between 00 00 00.0N 00 00 00.0W and 00 00 00.1N 00 00 00.1W is 4.3 meters
or between 00 00 00.0N 00 00 00.0W and 00 00 00.1N 00 00 00.0W is 3.0 meters

Our dashcams aren't accurate to closer than 3 meters so only 1 decimal place is required... clearly Google Maps also believes that only 1 decimal place is required... and if I was typing it in then I wouldn't normally bother with the decimal place because 30 meters is normally close enough for me to find the location on the map. Plus it only updates once a second and on the motorway I will be moving faster than 30 meters per second!
 

Kremmen

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#17
Good point.

I wonder what a table of accuracy would look like ?

1 decimal place = xx ft
2
3
4
5

I use my dashcam to pinpoint speed cameras for another site and they put their cameras into the database using 5 decimals max, where necessary. That allows them to show the side of the road the camera is on with good accuracy.
An example of one camera is 51.531,-0.39728
 

Nigel

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#18
Good point.

I wonder what a table of accuracy would look like ?

1 decimal place = xx ft
2
3
4
5

I use my dashcam to pinpoint speed cameras for another site and they put their cameras into the database using 5 decimals max, where necessary. That allows them to show the side of the road the camera is on with good accuracy.
An example of one camera is 51.531,-0.39728
The difference between 0N 0W and 0.00001N 0W is 1.1meters, so to tell which side of the road it is on you would need your 5, but in reality normal GPS isn't that accurate so they would need to take the average of several reports anyway and 4 would probably be enough.
 

kohakoo

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#19
In poost 5 you were talking about accuracy, which is what I tried to point out.

Three places of decimals on latitude 0° 00′ 0.036″ (three places) gives an accuracy of about 1m to get a similar accuracy (1.113m) you need D.D of 0.00001 (5 places). However that is to an accuracy level that is not supported by the dashcam.
So it would appear that a absolute max of five places D.DDDDD or thre places DMS.S should be applied tho the dashcam readout as any greater accuracy is a waste of time.
I wouldn't mind seeing one decimal place, I would like to compare the accuracy of both of these cams using just one.

I have a 612GW Front and 512GW rear.

The car has been stationary for about five seconds.
 

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M8TJT

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#20
Sorry, I thought I had posted my source of info in post 15. It's HERE
Your wish is my command K.
 
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