# Need Some GPS Help



## codybear (Jun 27, 2002)

I'm new to the GPS world so please bare with me.
I received some GPS coordinates but they are laid out differently than whats on the GPS. For example here is one of the coordinates I received:

84°30'27.7" W

Here is how my GPS is laid out:

085°05.100W

The problem is that the GPS wont let me enter the digits in the same exact manner including moving the dot..

I have a Magellan Explorist 200.
Any advice?

Thanks
CB


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## Hunt4Ever (Sep 9, 2000)

84°30'27.7" W

Here is how my GPS is laid out:

085°05.100W

I would enter: 084 30.4616 W

The other thing you could do is read the manual and change the coordinate system from Degrees Minutes to Degrees Minutes Seconds and they should match up correctly.

To get the degrees minutes from you above coordinates, just divide the seconds portion by 60. (27.7/60) is .4616


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## codybear (Jun 27, 2002)

By George that was it!!!! You da man!

I have to use the division factor because my GPS doesnt have the "Degrees Minutes Seconds" choice.

Thank you!

CB




Hunt4Ever said:


> 84°30'27.7" W
> 
> Here is how my GPS is laid out:
> 
> ...


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## codybear (Jun 27, 2002)

Another rookie question:
How much of a difference in feet is the very last digit? For example,

084 30.4616 W (vs) 084 30.4615 W

And is it the same difference if I change the last digit on a North coordinate?

Thanks
CB


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## hitechman (Feb 25, 2002)

One thousandth of one minute (.001) of latitude is 25000 x 5280 / (360 x 60 x 1000) feet = *6 1/9 feet*. The is constant worldwide as these lines are parallel.  Sooooo................yur asking about 1/10,000, and that would be about 7 inches. (.6 feet)

Longitude is a different story as the line are further apart on the equator and meet at the poles...............so as you move north the distance would decrease (and become 0 at the poles).

One thousandth of one minute of longitude is cos(latitude) * (6 1/9 feet). 

In NYC, the latitude is 40 degrees 43 minutes, .001 minutes of longitude is 4.63 feet. 
In Chicago, where the latitude is 39 degrees 44 minutes, .001 minutes of longitude is 4.70 feet. 
At the Arctic Circle (66 degrees 34 minutes ), .001 minutes of longitude is 2.43 feet. 
At the Tropic of Cancer (23 degrees, 27 minutes), .001 minutes of longitude is 5.61 feet. 
At the Equator, .001 minutes of longitude is 6.11 feet. 

So at the 45th parallel (runs through Michigan) each .001 minute of longitude would be close to 3 feet and each .0001 minute of latitude would be about .3 feet (3 1/2) inches.

Hope this answers your question.

Steve


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## codybear (Jun 27, 2002)

Thanks Steve, that was so helpfull I'm going to print that out and keep it with my GPS documents.

Thanks again Steve
CB




hitechman said:


> One thousandth of one minute (.001) of latitude is 25000 x 5280 / (360 x 60 x 1000) feet = *6 1/9 feet*. The is constant worldwide as these lines are parallel.  Sooooo................yur asking about 1/10,000, and that would be about 7 inches. (.6 feet)
> 
> Longitude is a different story as the line are further apart on the equator and meet at the poles...............so as you move north the distance would decrease (and become 0 at the poles).
> 
> ...


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## hitechman (Feb 25, 2002)

says that the formating of coordinates in the Explorist 200 can be changed to minutes, degrees, and seconds, but just says the guy did it, and not how it was done.

http://www.gunmuse.com/Reviews/Magellan Explorist 200 GPS

I find it hard to believe that any GPSr made today does not have that capability....humm!

Steve


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## kitty123 (Sep 6, 2007)

it said sth


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## Ralph Smith (Apr 1, 2003)

hitechman said:


> One thousandth of one minute (.001) of latitude is 25000 x 5280 / (360 x 60 x 1000) feet = *6 1/9 feet*. The is constant worldwide as these lines are parallel.  Sooooo................yur asking about 1/10,000, and that would be about 7 inches. (.6 feet)
> 
> Longitude is a different story as the line are further apart on the equator and meet at the poles...............so as you move north the distance would decrease (and become 0 at the poles).
> 
> ...



I'm a little confused here, never used a gps, but you said the lattitude is constant in the beginning of post and about 7" for .0001, then at bottom of post said 3 1/2". Am I reading this wrong? Would like to figure this out before I buy one, plus would like to figure distance off shore to go to certain spots on a maptech map online that has coordinates listed. Thanks for any help.


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## hitechman (Feb 25, 2002)

Ralph Smith said:


> I'm a little confused here, never used a gps, but you said the lattitude is constant in the beginning of post and about 7" for .0001, then at bottom of post said 3 1/2". Am I reading this wrong? Would like to figure this out before I buy one, plus would like to figure distance off shore to go to certain spots on a maptech map online that has coordinates listed. Thanks for any help.



Latitude is CONSTANT. Longitude changes because these lines are not parallel )they are farthest apart at the equator and meet at the poles. The 3 1/2 inches refers to longitude (not latitude).

No GPS any of us will buy (presently) has that accuracy--if you can get within 10 feet you're doing great.

Google it--lots of information out there.

Steve


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## Ralph Smith (Apr 1, 2003)

hitechman said:


> Latitude is CONSTANT. Longitude changes because these lines are not parallel )they are farthest apart at the equator and meet at the poles. The 3 1/2 inches refers to longitude (not latitude).
> 
> No GPS any of us will buy (presently) has that accuracy--if you can get within 10 feet you're doing great.
> 
> ...



I guess what I'm trying to figure is on this map site...http://mapserver.maptech.com/homepa...cfm&bpid=MAP0060030900,1,1,0&latlontype=DM.MM 
when I follow the cursor from the shore north it shows the lattiude numbers going up. Was trying to figure how far each (second I guess) would be apart to find out how far from shore a point would be? So would each second be about 3 feet?


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## hitechman (Feb 25, 2002)

Ralph Smith said:


> I guess what I'm trying to figure is on this map site...http://mapserver.maptech.com/homepa...cfm&bpid=MAP0060030900,1,1,0&latlontype=DM.MM
> when I follow the cursor from the shore north it shows the lattiude numbers going up. Was trying to figure how far each (second I guess) would be apart to find out how far from shore a point would be? So would each second be about 3 feet?


There is a formula involving some trigonometry and geometry (somewhat complex for the inexperienced) where you couls calcultae the distance, but why bother when this is available (just plug in your numbers-p-make sure you use 1 of the valid formats listed on the bottom of the page):

http://jan.ucc.nau.edu/~cvm/latlongdist.html

Look at the valid coordinates this calculator will accept, then choose how the coordinates are displayed as you move the cursor (selection just below the lat/long display on the lower left side of the map).

As I said above--there is almost unlimited information and resources on the web about this topic.

Steve

PS: Remember the distance between longitude lines changes as your distance from the equator (poles) changes, so it is not a constant change. 3 feet would be a good estimate at this longitude (I didn't actually calculate it). Each second is .017 minutes and not .001 minutes--the are 60 seconds in a minute, 60 minutes in 1 degree, and 360 degrees in one circle.

Steve


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## Ralph Smith (Apr 1, 2003)

o.k. thanks a bunch. I better get to work before I'm late:lol: Now I just have to decide on a gps to get


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## hitechman (Feb 25, 2002)

Ralph Smith said:


> .........................Now I just have to decide on a gps to get


*GARMIN*......................Lowrance will work too. I'd suggest staying away from Magellan (IMHO and experience). Actually, from what I hear (have never owned one) Lowrance has some great lake maps available).

Steve


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## huntingmaniac45 (Nov 22, 2005)

Man, I just got a headache reading this post.:lol:


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