Calculating Seconds

[+scuba inst]

There is a cache that I need to add 15 seconds to the starting coordinates to get the final spot. Someone tried explaing about decimal minutes, divide by sixty, etc. and that I need to add .25 and I still screwed it up. Let's pretend I think 2 + 2=5 and use an example N 40 39.465 and W 089 34.253. I think if I see the answer I can better understand what it means. I know this sounds like I'm trying to weasle out of this, but I've tried to understand it myself and it's not sinking through the thick noggin. Thanks

[+Stunod]

There is a cache that I need to add 15 seconds to the starting coordinates to get the final spot. Someone tried explaing about decimal minutes, divide by sixty, etc. and that I need to add .25 and I still screwed it up. Let's pretend I think 2 + 2=5 and use an example N 40 39.465 and W 089 34.253. I think if I see the answer I can better understand what it means. I know this sounds like I'm trying to weasle out of this, but I've tried to understand it myself and it's not sinking through the thick noggin. Thanks

15 seconds * 60 seconds/minute = 0.25 minutes

So adding this to both your lat & lon gives:

 

N 40 39.715 and W 089 34.503

[+Intarsiac]

Seconds in this case are not "time seconds", they are divisions of a degree: One degree = 60 minutes of arc, one minute = 60 seconds of arc. So 15 seconds is 15/60 of a minute or 1/4 of a minute or .25 of a minute.

N 40 39.465 is 40 degrees, 39.465 minutes. You need to add .25 minutes.

So, N 40 39.465 + .25 = N 40 39.715.

For the longitude:

W 089 34.253 = 89 degrees, 34.253 minutes, add .25 minutes to get, W 089 34.503.

Hope this helps!

 

Edit: Have to learn to type quicker than Stunod!

Edited July 8, 2004 by Intarsiac

[+Stunod]

Edit: Have to learn to type quicker than Stunod!

At least we got the same answer

[+EraSeek]

Seconds in this case are not "time seconds", they are divisions of a degree: One degree = 60 minutes of arc, one minute = 60 seconds of arc. So 15 seconds is 15/60 of a minute or 1/4 of a minute or .25 of a minute.

N 40 39.465 is 40 degrees, 39.465 minutes. You need to add .25 minutes.

So, N 40 39.465 + .25 = N 40 39.715.

For the longitude:

W 089 34.253 = 89 degrees, 34.253 minutes, add .25 minutes to get, W 089 34.503.

Hope this helps!

 

Edit: Have to learn to type quicker than Stunod!

Ok, say it was time seconds...

a globe is 360 degrees around.

The Earth rotates 360 degrees in 24 hours.

360 divided by 24hours = 15 degrees in 1 hour

or 900 minutes in one hours time

or 54000 seconds in 1 hours time

and so 900 seconds in 1 minutes time

and so 15 seconds in 1 seconds time

divide by 60 to get minutes of longitude

and you get 0.25 minutes of longitude in one second's time

 

(I have a couple of caches like this)

[+writer]

You could do everything in UTM instead - it's all linear measurements, though in meters. But expressing differences should be easier. Then you can either use one of the sites to do the conversion, or you can put the coordinates into your GPSr and then shift coordinate types to lat/lon.

[+Olar]

Seconds in this case are not "time seconds", they are divisions of a degree: One degree = 60 minutes of arc, one minute = 60 seconds of arc.  So 15 seconds is 15/60 of a minute or 1/4 of a minute or .25 of a minute. 

N 40 39.465 is 40 degrees, 39.465 minutes.  You need to add .25 minutes.

So, N 40 39.465 + .25 = N 40 39.715.

For the longitude:

W 089 34.253 = 89 degrees, 34.253 minutes, add .25 minutes to get, W 089 34.503.

Hope this helps!

 

Edit: Have to learn to type quicker than Stunod!

Ok, say it was time seconds...

a globe is 360 degrees around.

The Earth rotates 360 degrees in 24 hours.

360 divided by 24hours = 15 degrees in 1 hour

or 900 minutes in one hours time

or 54000 seconds in 1 hours time

and so 900 seconds in 1 minutes time

and so 15 seconds in 1 seconds time

divide by 60 to get minutes of longitude

and you get 0.25 minutes of longitude in one second's time

 

(I have a couple of caches like this)

Now tell me please. Is that based on walking the trail in the same direction as the Earth's rotation? If so then if you stop to rest then the cache will get further away. Or, rest long enough that it comes back around?

[+EraSeek]

Well, of course, this is based on the Earth's speed of advance or withdrawal from the Prime Meridian. This is why the early mariners (not baseball) so desperately needed the development of a cronometer. With an accurate timepiece they could judge local noon against noon at Grenwich (sp?), and thus cacalulate thier longitudinal postion fairly accurarately. Before that, they had very complex calulations that needed to be made or they simplly traveled basically blind, which was most often the case.