Lat/Lon distance question

Diver1111 · 08-14-2011, 09:42 PM

Can somebody tell me how far apart-in feet-two objects are given the following Lat/Lon specs.

Lat/Lon format I'm using is xx yy.zzz

Object #1 48 36.579 / 77 23.319

Object #2 48 36.568 / 77 27.359

When I hike I use the UTM/Universal Transverse Mercator coordinate system in the GPS-one convenient increment: meters, so you can tell exactly how far something is. Not so here at least I don't have a mind for the whole Lat/Lon thing and it variations.

Thanks.

SteveA · 08-15-2011, 06:22 AM

I used the numbers from the post and the ruler function on Google Earth, I added the N and W to the numbers you posted.

Frame of reference, these co-ordinates are in Canada

Name: distance.jpg
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Name: distance.jpg
Views: 629
Size: 58.1 KB

Slickcraft · 08-15-2011, 07:05 AM

We also use UTM on the GPS when hiking, easy to locate on the topo map.

To solve your geometry problem convert your lat/long to UTM, many sites out there such as http://www.rcn.montana.edu/resources...ordinates.aspx and
http://www.ngs.noaa.gov/cgi-bin/utm_getut.prl

Assuming your data is in degrees; decimal minutes format I get (subject to keyboard errors)
a distance of 4,964.9 meters (16,289 feet) at a bearing of 88.4 degrees.

SteveA · 08-15-2011, 11:36 AM

The way I did it was just using the ruler tool on Google earth and came up with the 16,181 shown in the clip I added. Definitely not an exact number because I'm just dragging it from point to point. Not very exact.

I'd say his is likely right on the money.

Rusty · 08-15-2011, 11:49 AM

Quote:

Originally Posted by SteveA

The way I did it was just using the ruler tool on Google earth and came up with the 16,181 shown in the clip I added. Definitely not an exact number because I'm just dragging it from point to point. Not very exact.

I'd say his is likely right on the money.

I like the way that you did it.....pretty clever!!

bkgoodman · 08-15-2011, 05:02 PM

In case you need to know - this is called a "Great Circle Distance" - as you are finding a distance between two points on a sphere. (Actually, an ellipsoid, but I'm assuming you don't need to be that accurate.)

I calculated a distance of 4.950 km or 16,240 feet.

Quick calculator is:

http://www.movable-type.co.uk/scripts/latlong.html

Kamper · 08-19-2011, 07:35 AM

If you trust the "meters" result, multiply X39 1/3, then divide by 12.

Diver1111 · 08-19-2011, 04:29 PM

Thank you all-very helpful.

NoBozo · 08-19-2011, 05:11 PM

Nautical Charts have the degrees, minutes and seconds ticked off..both across the bottom of the chart..look for the tick marks...AND vertically along the sides of the chart.

I can't speak for Topo Charts.

ONE Degree of Latitude..that's on the SIDE of the chart running vertically along the side ..represents 60 Nautical Miles..which is somewhat more than a LAND Mile. SO: One Minute of Latitude would be ONE Mile.

There is a conversion for Nautical miles to Land miles.

You can take a pair of "dividers" and measure off the Minutes from the Side of the chart and then "take off" the distance with the dividers http://en.wikipedia.org/wiki/Dividers#Divider_caliper.. and measure in any direction to measure distance for short distances..hundreds of miles..?

This.....with todays technology..is unnecessary.

One minute of Latitude = one nautical mile...absolute...

I learned this from my Study and Practice of Celestial Navigation in the late Seventy's...

NB

PS: I have pondered (days) whether to respond to this thread because the topic is "Technical" and I probably would not be able to describe it in "Ley" terms. Nobody does Celestial Navigation anymore.

Post Note: I could explain the Miles..Vs Nautical Miles..MPH...Vs Knots...it's all wrapped up in conversions.......but it would just get worse..........

Slickcraft · 08-19-2011, 06:49 PM

IMHO the UTM system is the easiest to use.

http://en.wikipedia.org/wiki/Univers...rdinate_system

It was developed by the Army and is still used by the artillery folk.

The easterly is meters east of a reference line within one of sixty zones. The northerly is simply meters north of the equator. The grid on a USGS TOPO map is a square kilometer grid with the UTM coordinates noted at each grid line.

I can't see why anyone would want to use a lat/long system in the field.

08-15-2011, 07:05 AM	#3
Slickcraft Senior Member Join Date: Mar 2008 Location: Welch Island and West Alton Posts: 3,218 Thanks: 1,173 Thanked 2,002 Times in 915 Posts	We also use UTM on the GPS when hiking, easy to locate on the topo map. To solve your geometry problem convert your lat/long to UTM, many sites out there such as http://www.rcn.montana.edu/resources...ordinates.aspx and http://www.ngs.noaa.gov/cgi-bin/utm_getut.prl Assuming your data is in degrees; decimal minutes format I get (subject to keyboard errors) a distance of 4,964.9 meters (16,289 feet) at a bearing of 88.4 degrees. Last edited by Slickcraft; 08-15-2011 at 11:03 AM. Reason: add result

08-15-2011, 11:36 AM	#4
SteveA Deceased Member Join Date: Jul 2006 Location: Gilford, NH Posts: 2,311 Thanks: 1,070 Thanked 2,054 Times in 497 Posts	I'd go with Slickcraft's math The way I did it was just using the ruler tool on Google earth and came up with the 16,181 shown in the clip I added. Definitely not an exact number because I'm just dragging it from point to point. Not very exact. I'd say his is likely right on the money. __________________ "Before you criticize someone, walk a mile in his shoes. That way, if he gets angry he'll be a mile away and barefoot!" unknown

08-19-2011, 04:29 PM	#8
Diver1111 Senior Member Join Date: Jun 2005 Location: Exeter NH Posts: 596 Thanks: 0 Thanked 1,027 Times in 224 Posts	Distance question Thank you all-very helpful.

08-19-2011, 05:11 PM	#9
NoBozo Senior Member Join Date: Jun 2008 Location: Portsmouth. RI Posts: 2,231 Thanks: 400 Thanked 460 Times in 308 Posts	Nautical Charts have the degrees, minutes and seconds ticked off..both across the bottom of the chart..look for the tick marks...AND vertically along the sides of the chart. I can't speak for Topo Charts. ONE Degree of Latitude..that's on the SIDE of the chart running vertically along the side ..represents 60 Nautical Miles..which is somewhat more than a LAND Mile. SO: One Minute of Latitude would be ONE Mile. There is a conversion for Nautical miles to Land miles. You can take a pair of "dividers" and measure off the Minutes from the Side of the chart and then "take off" the distance with the dividers http://en.wikipedia.org/wiki/Dividers#Divider_caliper.. and measure in any direction to measure distance for short distances..hundreds of miles..? This.....with todays technology..is unnecessary. *One minute* of Latitude = one nautical mile.*..absolute... I learned this from my Study and Practice of Celestial Navigation in the late Seventy's... NB PS: I have pondered (days) whether to respond to this thread because the topic is "Technical" and I probably would not be able to describe it in "Ley" terms. Nobody does Celestial Navigation anymore. Post Note: I could explain the Miles..Vs Nautical Miles..MPH...Vs Knots...it's all wrapped up in conversions.......but it would just get worse.......... Last edited by NoBozo; 08-19-2011 at 06:24 PM.*

08-14-2011, 09:42 PM	#1
Diver1111 Senior Member Join Date: Jun 2005 Location: Exeter NH Posts: 596 Thanks: 0 Thanked 1,027 Times in 224 Posts	Lat/Lon distance question Can somebody tell me how far apart-in feet-two objects are given the following Lat/Lon specs. Lat/Lon format I'm using is xx yy.zzz Object #1 48 36.579 / 77 23.319 Object #2 48 36.568 / 77 27.359 When I hike I use the UTM/Universal Transverse Mercator coordinate system in the GPS-one convenient increment: meters, so you can tell exactly how far something is. Not so here at least I don't have a mind for the whole Lat/Lon thing and it variations. Thanks.

08-15-2011, 06:22 AM	#2
SteveA Deceased Member Join Date: Jul 2006 Location: Gilford, NH Posts: 2,311 Thanks: 1,070 Thanked 2,054 Times in 497 Posts	Maybe this? I used the numbers from the post and the ruler function on Google Earth, I added the N and W to the numbers you posted. Frame of reference, these co-ordinates are in Canada __________________ "Before you criticize someone, walk a mile in his shoes. That way, if he gets angry he'll be a mile away and barefoot!" unknown

The Following User Says Thank You to SteveA For This Useful Post:
Rusty (08-15-2011)

08-15-2011, 05:02 PM	#6
bkgoodman Senior Member Join Date: Sep 2010 Location: Nashua, NH Posts: 66 Thanks: 27 Thanked 16 Times in 6 Posts	In case you need to know - this is called a "Great Circle Distance" - as you are finding a distance between two points on a sphere. (Actually, an ellipsoid, but I'm assuming you don't need to be that accurate.) I calculated a distance of 4.950 km or 16,240 feet. Quick calculator is: http://www.movable-type.co.uk/scripts/latlong.html

08-19-2011, 07:35 AM	#7
Kamper Senior Member Join Date: Jul 2005 Location: Thornton's Ferry Posts: 1,296 Thanks: 67 Thanked 166 Times in 126 Posts	If you trust the "meters" result, multiply X39 1/3, then divide by 12.

08-19-2011, 06:49 PM	#10
Slickcraft Senior Member Join Date: Mar 2008 Location: Welch Island and West Alton Posts: 3,218 Thanks: 1,173 Thanked 2,002 Times in 915 Posts	IMHO the UTM system is the easiest to use. http://en.wikipedia.org/wiki/Univers...rdinate_system It was developed by the Army and is still used by the artillery folk. The easterly is meters east of a reference line within one of sixty zones. The northerly is simply meters north of the equator. The grid on a USGS TOPO map is a square kilometer grid with the UTM coordinates noted at each grid line. I can't see why anyone would want to use a lat/long system in the field.