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Old 01-02-2016, 00:29   #1
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Different numbers for "Seconds" in Lats and longs?

Pardon my lack of education, but why is it that some programs will give you the "seconds" in numbers like "873" or "785" and other programs will only go to "599" in seconds? I had a friend send me some coordinates for anchoring and he was using a program that uses the "873" and the "785" but mine doesn't go that high.
Is there an easy conversion method so I don't get lost or up on a reef?
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Old 01-02-2016, 00:58   #2
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Re: Different numbers for "Seconds" in Lats and longs?

If it exceeds 599, then it is fair bet that the numbers are decimal places of minutes.

So 4 minutes 45 seconds can also be 4.750 minutes etc.
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Old 01-02-2016, 01:57   #3
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Re: Different numbers for "Seconds" in Lats and longs?

The two most common formats are either
Degrees, Minutes and Seconds (ie 25° 45' 36"N),
or in degrees, minutes and decimals of minutes (ie 25° 45'.6N.

I'm not sure as to 599 seconds, would that not be 59.9 seconds, as there are only 60 seconds in one minute.

Which nav program are you using, as most will allow an option of either using seconds, or decimals of minutes.
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Old 01-02-2016, 01:59   #4
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Re: Different numbers for "Seconds" in Lats and longs?

actualy it should be "exceeds 59.9"
seconds are usualy only displayed as fraction of a minute unless on very large scale maps (i.e. you zoom in very far)
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Old 01-02-2016, 03:09   #5
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Re: Different numbers for "Seconds" in Lats and longs?

All GPSs and chartplotters can be changed so that you can enter the figures given to you and then change back to what you like. The mark will then show as the converted number.

For example, if you are given one as S34° 03.125' E151° 06.500 (this is the sort of number you are referring to), you change your GPS from degrees minutes seconds to degrees minutes (sometimes called degrees decimal minutes), enter the figures, then change back to degrees minutes seconds. The mark will now show as S34° 03' 15" E151° 06' 30".

You can also do a similar thing if you are given marks with a different datum.
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Old 01-02-2016, 05:02   #6
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Re: Different numbers for "Seconds" in Lats and longs?

You can present lat/long
- Decimal degrees: ie: 27.38485485 degrees
- Degree and decimal minutes: 27 deg 34.484832min
- Degree, min and decimal seconds: 27 deg 34min 23.3425sec

The math isn't too difficult but it is a pain to switch back and forth. My guess is your buddy provided degree and decimal minutes.
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Old 01-02-2016, 06:43   #7
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Re: Different numbers for "Seconds" in Lats and longs?

"will only go to "599" in seconds"....can not be and deffiniteli something is wrong here, your GPS (not set up properly) or your understanding of GPS readings. must go to 999.

example: 45° 56'.975. '.975 will go '.976, 978, 979.....until it reach '.999 then it will be full minutes so it will be 45° 57'.000

59.9 sec : 60 = 0.9983333333333333


you did not gave us whole "number", maybe in those "873" or "785" are included minutes as well as seconds.so those "873" will actually be
52'.3 so let say if you have 45°52'.3 can also be 45.873°
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Old 01-02-2016, 10:20   #8
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Re: Different numbers for "Seconds" in Lats and longs?

Quote:
Originally Posted by nigel1 View Post
The two most common formats are either
Degrees, Minutes and Seconds (ie 25° 45' 36"N),
or in degrees, minutes and decimals of minutes (ie 25° 45'.6N.

I'm not sure as to 599 seconds, would that not be 59.9 seconds, as there are only 60 seconds in one minute.

Which nav program are you using, as most will allow an option of either using seconds, or decimals of minutes.
Occasionally degrees with many decimals are used, especially on sites like google maps. For example 44.12345 N 76.54321 W
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Old 01-02-2016, 10:24   #9
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Re: Different numbers for "Seconds" in Lats and longs?

To convert the number of minutes to a decimal value, use the following formula:
Decimal value = Minutes/60
As an example, a latitude of 122 degrees 45 minutes North is equal to 122.75 degrees North.
To convert Seconds to decimals, divide by 3600.
Decimal value = Seconds/3600
As an example, a latitude of 122 degrees 45 minutes 45 seconds North is equal to 122.7625 degrees North.
So the complete formula looks similar the following:
Decimal value = Degrees + (Minutes/60) + (Seconds/3600)

different formats:

degrees minutes seconds: 40° 26′ 46″ N 79° 58′ 56″ W

degrees decimal minutes: 40° 26.767′ N 79° 58.933′ W

decimal degrees: 40.446° N 79.982° W
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Old 01-02-2016, 10:27   #10
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Re: Different numbers for "Seconds" in Lats and longs?

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Originally Posted by valhalla360 View Post
You can present lat/long
- Decimal degrees: ie: 27.38485485 degrees
- Degree and decimal minutes: 27 deg 34.484832min
- Degree, min and decimal seconds: 27 deg 34min 23.3425sec

The math isn't too difficult but it is a pain to switch back and forth. My guess is your buddy provided degree and decimal minutes.
To convert from decimal minutes to seconds...multiply the decimal part only by 60...and thats your seconds.

To convert from decimal degrees to minutes...multiply the decimal part only by 60...and thats your minutes.

So,

44.12345 North

= 44 + (.12345 x 60) minutes N
= 44 degrees, 7.407 minutes N
= 44 degrees, 7 minutes, (.407 x 60) seconds N
= 44 degrees, 7 minutes, 24.4 seconds N

To convert the other way, divide by 60 instead.
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Old 01-02-2016, 15:07   #11
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Re: Different numbers for "Seconds" in Lats and longs?

After the first response, I checked the chart plotters setting and found where I can change them over to the decimal system. I was trained to use degrees, minutes and seconds years ago by the USCG and have used it ever since. When did they(heaven only knows who the "they" are)start changing things over to decimals. Couldn't "they" leave it well enough alone or am I just being and old, stick in the mud fart?
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Old 01-02-2016, 16:33   #12
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Re: Different numbers for "Seconds" in Lats and longs?

Quote:
Originally Posted by mestrezat View Post
After the first response, I checked the chart plotters setting and found where I can change them over to the decimal system. I was trained to use degrees, minutes and seconds years ago by the USCG and have used it ever since. When did they(heaven only knows who the "they" are)start changing things over to decimals. Couldn't "they" leave it well enough alone or am I just being and old, stick in the mud fart?
Even large scale paper charts show minutes and tenths of minutes on the lat and long scales.
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Old 01-02-2016, 16:53   #13
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Re: Different numbers for "Seconds" in Lats and longs?

Quote:
Originally Posted by mestrezat View Post
When did they(heaven only knows who the "they" are)start changing things over to decimals. Couldn't "they" leave it well enough alone or am I just being and old, stick in the mud fart?
when the human eye stopped beeing able to distinguish seconds on a mercator map.
oh wait. that was the other way around.
one arc-second is 30m or ~100ft, consider that.
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Old 01-02-2016, 17:00   #14
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Re: Different numbers for "Seconds" in Lats and longs?

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Originally Posted by Wotname View Post
If it exceeds 599, then it is fair bet that the numbers are decimal places of minutes.

So 4 minutes 45 seconds can also be 4.750 minutes etc.
Whatever the numbers are, it's a very good idea to know which system you are using.
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Old 01-02-2016, 21:43   #15
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Re: Different numbers for "Seconds" in Lats and longs?

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Originally Posted by hamburking View Post
To convert from decimal minutes to seconds...multiply the decimal part only by 60...and thats your seconds.

To convert from decimal degrees to minutes...multiply the decimal part only by 60...and thats your minutes.

So,

44.12345 North

= 44 + (.12345 x 60) minutes N
= 44 degrees, 7.407 minutes N
= 44 degrees, 7 minutes, (.407 x 60) seconds N
= 44 degrees, 7 minutes, 24.4 seconds N

To convert the other way, divide by 60 instead.
I didn't say the math was difficult. I said it was a nuisance. If you have to convert back and forth a lot, it's not something you can do quickly in your head.
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