| Home |
| Search |
| Today's Posts |
|
|
|
#1
|
|||
|
|||
Calculating distance from Lat/Long
On Thu, 04 Dec 2003 13:20:40 -0800, "Lloyd Sumpter"
wrote: Hi, I'm writing a program for Linux that displays position (from GPS) on a scanned-in chart, and would like it to calculate distance from current position to the cursor. How do you calculate distance between two points using lat/long? If they're due North/South, I can do it ( 1 minute of lat = 1 NM) but how do you calculate distance from longitude? Perhaps some formula based on the circumfrence of the Earth at the equator and the latitude? Lloyd Sumpter First, an explanatory note: inverse cos is also known as arc.cos or cos^-1 The great circle distance is given by Earth radius * arccos [cos Lat1* cos Lat2 * cos (Long1 - Long2) + sin Lat1 * sin Lat2] The Earth (equatorial) radius is 6378 km, or 3963 statute miles or 3442 NM. Does this help? (There are other formulae for the same result...) Brian Whatcott Altus OK |
|
#2
|
|||
|
|||
|
Calculating distance from Lat/Long
Fifty seven lurkers just headed for the Tylenols with their heads
spinning, feeling nauseated and dizzy....(c; I love my Nautical Almanac..... I love my Nautical Almanac..... I love my Nautical Almanac..... I love my Nautical Almanac..... and GPS... On Fri, 05 Dec 2003 00:27:38 GMT, Brian Whatcott wrote: First, an explanatory note: inverse cos is also known as arc.cos or cos^-1 The great circle distance is given by Earth radius * arccos [cos Lat1* cos Lat2 * cos (Long1 - Long2) + sin Lat1 * sin Lat2] The Earth (equatorial) radius is 6378 km, or 3963 statute miles or 3442 NM. Does this help? (There are other formulae for the same result...) Brian Whatcott Altus OK Larry W4CSC NNNN |
|
#3
|
|||
|
|||
|
Calculating distance from Lat/Long
"Larry W4CSC" wrote in message ... Fifty seven lurkers just headed for the Tylenols with their heads spinning, feeling nauseated and dizzy....(c; I love my Nautical Almanac..... I love my Nautical Almanac..... I love my Nautical Almanac..... I love my Nautical Almanac..... and GPS... Sounds like the old days with Oscar and his apples (to be polite). Oh... The is trig and not the sphere stuff..... Leanne |
|
#4
|
|||
|
|||
|
Calculating distance from Lat/Long
Not too surprising...I meant to mention that the inverse cos is
intended to provided an angle in *radians* 1 radian = 1 degree X 180/pi or about 57 degrees. Brian W On Fri, 05 Dec 2003 02:51:48 GMT, (Larry W4CSC) wrote: Fifty seven lurkers just headed for the Tylenols with their heads spinning, feeling nauseated and dizzy....(c; I love my Nautical Almanac..... I love my Nautical Almanac..... I love my Nautical Almanac..... I love my Nautical Almanac..... and GPS... On Fri, 05 Dec 2003 00:27:38 GMT, Brian Whatcott wrote: First, an explanatory note: inverse cos is also known as arc.cos or cos^-1 The great circle distance is given by Earth radius * arccos [cos Lat1* cos Lat2 * cos (Long1 - Long2) + sin Lat1 * sin Lat2] The Earth (equatorial) radius is 6378 km, or 3963 statute miles or 3442 NM. Does this help? (There are other formulae for the same result...) Brian Whatcott Altus OK Larry W4CSC NNNN |
|
#5
|
|||
|
|||
|
Calculating distance from Lat/Long
On Fri, 05 Dec 2003 04:04:13 GMT, Brian Whatcott
wrote: Not too surprising...I meant to mention that the inverse cos is intended to provided an angle in *radians* 1 radian = 1 degree X 180/pi or about 57 degrees. Brian W My head is still buzzin', but that might be the Boddington's Ale, not spherical trig....(c; Larry W4CSC NNNN |
|
#6
|
|||
|
|||
|
Calculating distance from Lat/Long
They have Boddingtons in W4 land???
Wow.. I wondered why you send all the Bud over here!! Bob GM4CAQ "Larry W4CSC" wrote in message ... On Fri, 05 Dec 2003 04:04:13 GMT, Brian Whatcott wrote: Not too surprising...I meant to mention that the inverse cos is intended to provided an angle in *radians* 1 radian = 1 degree X 180/pi or about 57 degrees. Brian W My head is still buzzin', but that might be the Boddington's Ale, not spherical trig....(c; Larry W4CSC NNNN |
|
#7
|
|||
|
|||
|
Calculating distance from Lat/Long
On Tue, 16 Dec 2003 00:00:59 -0000, "Robert Miles"
wrote: They have Boddingtons in W4 land??? Wow.. I wondered why you send all the Bud over here!! Bob GM4CAQ America is awash in English Ale....(c; THANKS!! Larry W4CSC NNNN |
|
#8
|
|||
|
|||
|
Calculating distance from Lat/Long
On Tue, 16 Dec 2003 00:00:59 -0000, "Robert Miles"
wrote: They have Boddingtons in W4 land??? Wow.. I wondered why you send all the Bud over here!! Bob GM4CAQ America is awash in English Ale....(c; THANKS!! Larry W4CSC NNNN |
|
#9
|
|||
|
|||
|
Calculating distance from Lat/Long
They have Boddingtons in W4 land???
Wow.. I wondered why you send all the Bud over here!! Bob GM4CAQ "Larry W4CSC" wrote in message ... On Fri, 05 Dec 2003 04:04:13 GMT, Brian Whatcott wrote: Not too surprising...I meant to mention that the inverse cos is intended to provided an angle in *radians* 1 radian = 1 degree X 180/pi or about 57 degrees. Brian W My head is still buzzin', but that might be the Boddington's Ale, not spherical trig....(c; Larry W4CSC NNNN |
|
#10
|
|||
|
|||
|
Calculating distance from Lat/Long
On Fri, 05 Dec 2003 04:04:13 GMT, Brian Whatcott
wrote: Not too surprising...I meant to mention that the inverse cos is intended to provided an angle in *radians* 1 radian = 1 degree X 180/pi or about 57 degrees. Brian W My head is still buzzin', but that might be the Boddington's Ale, not spherical trig....(c; Larry W4CSC NNNN |
| Reply |
|
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Forum | |||
| Long Distance carrier for cruisers? | General | |||
Hybrid Mode
