Mapping Coordinates

Submitted: Monday, Jun 08, 2009 at 16:07
ThreadID: 69615 Views:2737 Replies:5 FollowUps:15
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Mapping Coordinates………………………What is going on with using two types of map coordinates, most of the latest map (HEMA) books that I have show the coordinates in degrees minutes seconds, but I see that some of the web sites are now using decimal coordinates……..Is it a Ford/Holden thing or is there a world wide change to using the decimal coordinates
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Reply By: Member - The Bushwhackers -NSW - Monday, Jun 08, 2009 at 16:18

Monday, Jun 08, 2009 at 16:18
Hey Cobber, one of my pet hates! A bit harder to plan a trip when the coordinates are mixed. I personally prefer UTM, but it seems I am alone there. It has frustrated me to the extent that I now have a program on my PC that converts any coordinate format into the others (not UTM). There is one in the members area that has been written in Excel, but yes, its a nuisance isn't it?
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Follow Up By: get outmore - Monday, Jun 08, 2009 at 16:24

Monday, Jun 08, 2009 at 16:24
UTM is better for using with maps and its not hard to wotk out how far away a waypoint is as its measured in metres.

for conveying info to other people in other states sometimes the degrees and minutes can be better as theres no confusuion over zones.

When i learned the difference i started sing UTM
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Follow Up By: Robin Miller - Monday, Jun 08, 2009 at 17:47

Monday, Jun 08, 2009 at 17:47
Definately not alone Whacker
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Follow Up By: The Explorer - Monday, Jun 08, 2009 at 17:52

Monday, Jun 08, 2009 at 17:52
I think the original post was about decimal degrees (or minutes) ...or was cobbers reference to "decimal coordinates" relating to UTM? Even talking about it can get confusing :)

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Greg
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Follow Up By: curious - Monday, Jun 08, 2009 at 17:54

Monday, Jun 08, 2009 at 17:54
UTM is nice to use.

However, in a commercial application we logged several thousand of our customer locations in decimal degrees as it was easier and unambiguous for data entry and we could standardise to six decimal places.

It is a hassle with a mixture of decimal degrees, decimal minutes and degrees/minutes/seconds. Conversion programs work ok but it would be good to have one standard. Can't see it happening though.
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Follow Up By: Member - The Bushwhackers -NSW - Monday, Jun 08, 2009 at 18:04

Monday, Jun 08, 2009 at 18:04
Hi Curious, I didnt think of the data entry side of things, just my own problems, being selfish :-). I am of the same opinion, one standard would be terrific, it will probably happen when there is world peace.....
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Reply By: The Explorer - Monday, Jun 08, 2009 at 17:48

Monday, Jun 08, 2009 at 17:48
Hi - there is no right or wrong way to define coordinates though under certain circumstance there are advantages in using one method over another. The use of decimals to define lats and longs has probably increased in popularity as many people use digital maps - some mapping programs either require coordinates in decimal format or its an option for output. The numbers all mean the same thing so just a case of being aware and prepared to utilise whatever numbers come your way.


Cheers
Greg
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Follow Up By: cobber - Monday, Jun 08, 2009 at 18:09

Monday, Jun 08, 2009 at 18:09
Hi Explorer,Thanks for the reply, I have no problem using either decimal or minutes/seconds, but why dont they!! make it one or the other, like pounds shillings pence to dollars and feet and inches to metric.............what I find frustrating is that most maps are in minutes and seconds and you find out about a good camp site with the coordinates in decimals.........Bugger..lol
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Follow Up By: The Explorer - Monday, Jun 08, 2009 at 18:41

Monday, Jun 08, 2009 at 18:41
Hi - I am still not sure if you mean UTM when you state "decimal coordinates" or decimal degrees (or minutes)....either way there will never be a standard - as I mentioned there are (real) advantages of using different formats in different circumstances, plus people will just have a personal preference irrespective of what others use.

The rise in popularity of computers, gps mapping programs, digital mapping and gps units has made it easy to convert between any system at the press of a button so I, personally, dont see any issue. I can however see how it can get confusing and frustrating for others though - been there myself once or twice.

Cheers
Greg

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Follow Up By:- Monday, Jun 08, 2009 at 19:03

Monday, Jun 08, 2009 at 19:03
UTM stands for Universal Transverse Mercator Projection and is not the reason why the issue of displaying Degrees Minutes and Seconds versus Degrees.decimal degrees arises. The only reason why Degrees.decimal degrees are now being used is because we now have computers and degrees.decimal degrees are easiy entered into computer files such as CSV and xls Files when recording POIs and such like. Degrees, Minutes and Second symbols are not recognised as a legitimate types of entry in these files. Nor can the symbols be entered into many web sites that easily. Its as simple as that. Also, Degrees.decimal degrees are easily added and subtracted which is not the case with Degrees Minutes and Seconds.

If you wish to convert Degrees.Decimal Degrees to Degrees Minutes and Seconds it is rather straight forward. Multiply the .decimal degrees by 60 and the resultant whole number are you minutes. Then multiply the remaining decimal value by 60 again and that the seconds.

For example 23 (degrees cause I can't enter the degrees symbol in this follow up) 24' 49" equals 23.41365 Degrees.

If you can't handle that then consider using Grid Values (Eastings and Northing in Metres) which are an alternate coordinate system. This system has inherent complications as well as with these you start talking about Zones which are in 6 degree bands of longitude around Australia.
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Follow Up By: The Explorer - Monday, Jun 08, 2009 at 19:20

Monday, Jun 08, 2009 at 19:20
"UTM stands for Universal Transverse Mercator Projection and is not the reason why the issue of displaying Degrees Minutes and Seconds versus Degrees.decimal degrees arises."

True - but no one said it was. As mentioned I am not sure if cobber is referring to coordinates in UTM or decimal degrees...he just states decimal coordinates. I, like you, suspect he is speaking about decimal degrees...but others (read above) have headed down the UTM path (fair enough - his comment is slightly ambiguous). In no instance was anyone suggesting UTM referred to decimal degrees.

"Degrees, Minutes and Second symbols are not recognised as a legitimate types of entry in these files."

Yes the symbols are not recognised but you can enter degrees, minutes and seconds (minus the symbols) into OziExplorer (either directly or via import of csv file) and it recognises them - not all programs are created equal:)

"I can't enter the degrees symbol in this follow up"

Yes you can - use Alt+176 and you get °

Cheers
Greg

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Follow Up By:- Monday, Jun 08, 2009 at 22:57

Monday, Jun 08, 2009 at 22:57
Greg,

No argument from me, I did interpret that there was some confusion and it would not be the first time.

I wish Alt+176 worked for me but it doesn't. Try as I might.

I understand that some programs like Ozi are capable of understanding degrees minutes & seconds. I just find that bulk editing of .txt files or xls files to ensure they are importable into Ozi makes Decimal degrees much easier operate with.

Whiles I still prefer the traditional method of representing geographic coordinates, I've found it expedient to switch to decimal degrees on occasions.

WBS (aka Toolman)
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Follow Up By: The Explorer - Monday, Jun 08, 2009 at 23:31

Monday, Jun 08, 2009 at 23:31
Sorry that was suppose to be Alt+0176

How to enter degree symbol

Cheers
Greg

I sent one final shout after him to stick to the track, to which he replied “All right,” That was the last ever seen of Gibson - E Giles 23 April 1874

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Follow Up By:- Tuesday, Jun 09, 2009 at 09:16

Tuesday, Jun 09, 2009 at 09:16
23° There! Got it!

I might add it didn't work at previous attempts because I was using the general keyboard, not the number pad. How dumb was that.

Thanks Greg

WBS
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Reply By: The Explorer - Tuesday, Jun 09, 2009 at 09:35

Tuesday, Jun 09, 2009 at 09:35
....oh and the other thing with using decimal coordinates (decimal lat/long or UTM) is accuracy. Quoting a location in whole degrees, minutes and seconds will limit you to an accuracy of about +/= 25 metres (varies depending on your latitude). This if fine for the average punter recording campsites, hills etc but is not accurate enough for other applications (eg drillholes, geocaching). Solution is of course to use decimal lat/long or UTM - the more decimals places the more accurate (accuracy then limited by the device you are recording the data with of course).

Cheers
Greg
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Follow Up By: get outmore - Tuesday, Jun 09, 2009 at 10:05

Tuesday, Jun 09, 2009 at 10:05
and then to make proper use of that accuracy you would need a DGPS type setup
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Follow Up By: The Explorer - Tuesday, Jun 09, 2009 at 10:20

Tuesday, Jun 09, 2009 at 10:20
True, past a certain point. The documented accuracy of handheld GPS units is typically +/- 5 metres (better if you are in a part of the world with WAAS/EGNOS)

So there is justification (about 20 metres of justification actually:) for using decimal Lat/Long or UTM instead of straight DMS even if not using a DGPS type stetup if you need some better accuracy when recording/passing on your data.

Cheers
Greg
I sent one final shout after him to stick to the track, to which he replied “All right,” That was the last ever seen of Gibson - E Giles 23 April 1874

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Reply By: Member - Mike DID - Wednesday, Jun 10, 2009 at 11:16

Wednesday, Jun 10, 2009 at 11:16
Just be thankful that the confusion over a different Datum is disappearing, now that most maps are GDA94.
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Reply By: Member - Mike DID - Wednesday, Jun 10, 2009 at 11:19

Wednesday, Jun 10, 2009 at 11:19
There are standards - it's just that every group has their own standards -

Marine - DMS

Aviation - DMD

Land - UTM or D.D
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Follow Up By: The Explorer - Wednesday, Jun 10, 2009 at 13:35

Wednesday, Jun 10, 2009 at 13:35
"Land - UTM or D.D"

Hi - Better tell the map makers - all the maps I have show lat/long as degress minutes and seconds (and usually UTM) - no decimals to be seen. If the "standard" is decimal degrees when did it come in? Do you have a reference for these "standards"?

I can believe there are standards that cover all aviation and marine applications....but think due to the wide range of different groups/users/applications for land that no one standard could be created and universally accepted.

Cheers
Greg
I sent one final shout after him to stick to the track, to which he replied “All right,” That was the last ever seen of Gibson - E Giles 23 April 1874

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