Jump to content

Converting coordinates


Followers 2

Recommended Posts

Let me preface this by saying that I know about the various coordinate calculation/conversion programs like geocalc. I am trying to teach middle school kids about geocaching and coordinates. Note that I am (obviously) not a teacher, I am just a parent. ;)

 

I found this wikipedia article on how to convert coordinates. Looking under the "Ways of writing coordinates" paragraph I understand the conversions between the first two and the last three sets or strings of coordinates. They are fairly straight forward if I keep track of units (degrees vs. min vs. sec) and think of the degrees as hours. I do note that I get a slightly different answer when converting from DMS 40:26:46N to DegDec. When I do the calculations, I get 40.446111N rather than 40.446195N on the web page. Why am I getting a different answer?

 

What I REALLY do NOT understand where how the third and fourth (40d 26' 21" N 79d 58' 36" W) coordinates come from. Where does the 21" come from? Doesn't the " mean seconds? So the third and fourth coordinate strings have 21 seconds? All of the other coordinate strings have 46 seconds or more specifically 46.302 seconds, right?

 

BTW=I know that difference between the third coordinate and the fourth coordinate just substitute the degree symbol for d. I don't know how to enter the degree symbol using my laptop since I don't have a number keypad on my laptop. I only have numbers on the top row and <alt176> doesn't work like it would if I was using the number keypad. How do I enter the degree symbol on my laptop?

 

 

One last question-am I correct in assuming that the coordinates listed on the geocaching pages are based on dd.mm.mmm? On the wikipedia article referenced above, this the last set of coordinates in that paragraph-right? So if we were looking at a geocaching.com cache page we would see the wikipedia location as N 40d 26.772 W 079d 56.932.

 

Ok, this is really my last question. Converting to UTM requires trig and algebra right? I don't want to go there. :(

 

Thanks for your time.

Link to comment

* 40:26:46N,79:56:55W

* 40:26:46.302N 79:56:55.903W

* 40°26'21"N 79°58'36"W

* 40d 26' 21" N 79d 58' 36" W

* 40.446195N 79.948862W

* 40.446195, -79.948862

* 40° 26.7717, -79° 56.93172

 

Well it's a bit misleading, but the article doesn't actually say all of those are equivalent values. It's just saying that those are different ways to write coordinates. It's kind of confusing, though, that some are the same and some are just kind of close. It's just one of those things about wikipedia -- volunteer authors aren't the most pedagogical.

 

But anyway...

 

The second one

* 40:26:46.302N 79:56:55.903W

has a latitude of 40 degrees, 26 minutes, and 46.302 seconds.

It converts to 40 + 26*60 + 46.302*3600 = 40.446195 degrees (same as the fifth and sixth coordinates).

Or 40 degrees and 26+46.302*60=26.7717 minutes (same as the seventh coordinates)

 

The first coordinates listed are the same as the second ones, but rounded down to the second. So

* 40:26:46N,79:56:55W

has a latitude of 40 degrees, 26 minutes, and 46 seconds.

It converts to 40 + 26*60 + 46*3600 = 40.446111 degrees, the number you got.

 

The third and fourth are different coordinates for some reason, but close enough to be confusing. They're just showing different ways of writing DMS.

Link to comment
Ok, this is really my last question. Converting to UTM requires trig and algebra right?

Wrong. UTM is a completely different concept from lat and long. There is no easy conversion algorithm. For a full explanation of how it works again have a look at Wikepedia http://en.wikipedia.org/wiki/Universal_Tra...ordinate_system .

 

Most people do not use or understand UTM, but despite its artificial construct it is very practical. For instance, the least significant digit on both the Eastings and Northings represent one metre. Compare that to the lat and long system where one minute of latitude is one nautical mile and the longitude coordinate represent different distances depending on the corresponding latitude. :(

 

If you want to convert between the two you’ll need a s/w package. Your GPSr will also be able to convert for you.

 

Good luck with your trig ;)

Link to comment

BTW=I know that difference between the third coordinate and the fourth coordinate just substitute the degree symbol for d. I don't know how to enter the degree symbol using my laptop since I don't have a number keypad on my laptop. I only have numbers on the top row and <alt176> doesn't work like it would if I was using the number keypad. How do I enter the degree symbol on my laptop?

 

;) completely no idea about the conversions but to get the ° symbol as a 'reply' on here, "Lectroboy" says you will need to......

 

Hold "Alt" and then key in 0176 then release "Alt". ( think you may have missed pressing the '0' or is that a typo?)

 

0r go to 'accessories' and open "charecter" map where you can choose your own ' symbol' and note the 'shortcut'

 

I also have a step by step guide to inserting it into a word document if you need it?

I'll insert it here anyway you could always 'cut and paste' (the way 'Minxyy' would have done it :( )

 

To get a ° sign you will need to

 

1. Open a word document

2. Click on 'insert' from the toolbar

3. Click on 'symbols'

4. Which will open a new window

5. Choose the symbol you want ( the ° in this case is on the top line on mine!)

6. I have had to reassign a shortcut key (so I remember where it is)

7. Click in the box that says 'shortcut key'

8. ‘Press new shortcut key'

9. Then use 'Ctrl + d' computes to 'Ctrl +D' (there may be a 'bodmas' enabling both 'd' and 'D' to mean the same thing!!!)

10. Remember it and then close and you should be up and running with your new symbol

 

minxyy

Edited by minxyy
Link to comment

The easiest way to get a ° symbol on a laptop is to copy it (ctrl-c) from an existing source i.e elsewhere in this post or a cache listing; then paste it (ctrl-v) into your post.

 

Another method on my laptop:

1. Use the "Fn" and "num lk" keys to activate the number pad located on the 7 8 9 U I O J K L & M keys.

2. Alt-0176 now works.

3. Use the "Fn" and "num lk" keys to reset the keyboad back to normal.

Link to comment
The easiest way to get a ° symbol on a laptop is to copy it (ctrl-c) from an existing source i.e elsewhere in this post or a cache listing; then paste it (ctrl-v) into your post.

 

Another method on my laptop:

1. Use the "Fn" and "num lk" keys to activate the number pad located on the 7 8 9 U I O J K L & M keys.

2. Alt-0176 now works.

3. Use the "Fn" and "num lk" keys to reset the keyboad back to normal.

 

:blink: ° ° :(

 

Super!! The number lock trick worked!! I also never thought about copying and pasting it.

 

Thanks

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Followers 2
×
×
  • Create New...