[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

From |
"Glen Waddell" <waddell@uoregon.edu> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
st: RE: Re: Latitude/longitude in spatwmat |

Date |
Mon, 29 Sep 2003 13:05:57 -0700 |

Michael Blasnik writes > Well, latitude to distance is fairly simple -- it's just the circumference of > the earth divided by 360, which equals about 69 miles. The longitude conversion > will vary with latitude. ... You can use some trig if you need to get more > precise. Agreed. The distance from {lat1,lon1} to {lat2,lon2} is simple. It is equal to radius*(acos(sin(lat1)*sin(lat2)+cos(lat1)*cos(lat2)*cos(lon2-lon1))) where radius is of Earth in miles and lat/lon are in radians. However, this does not solve the problem of projecting latitude and longitude onto an {x,y} plane. Glen ____________________________ Glen R. Waddell Department of Economics University of Oregon Eugene, OR 97403-1285 phone: (541) 346-1259 fax: (541) 346-1243 www.uoregon.edu/~waddell/ -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Michael Blasnik Sent: Monday, September 29, 2003 12:13 PM To: statalist@hsphsun2.harvard.edu Subject: st: Re: Latitude/longitude in spatwmat Well, latitude to distance is fairly simple -- it's just the circumference of the earth divided by 360, which equals about 69 miles. The longitude conversion will vary with latitude. At the equator (lat=0 degrees), one degree longitude equals one degree latitude. The value drops as move away from the equator of course. I think that at latitudes of 30, 40, and 50 degrees it's about 60, 53, and 44 miles respectively. You can use some trig if you need to get more precise. Michael Blasnik michael.blasnik@verizon.net ----- Original Message ----- From: "Glen Waddell" <waddell@uoregon.edu> To: "Statalist" <statalist@hsphsun2.harvard.edu> Sent: Monday, September 29, 2003 2:30 PM Subject: st: Latitude/longitude in spatwmat > > I currently have latitude and longitude coordinates in a dataset but > need to have them projected onto an {x,y} plane in order to take > advantage of the 'spatwmat' command. Do you know if there is a > conversion equation, or at least a legitimate approximation for small > areas? > > Glen > > ____________________________ > Glen R. Waddell > Department of Economics > University of Oregon > Eugene, OR 97403-1285 > phone: (541) 346-1259 > fax: (541) 346-1243 > www.uoregon.edu/~waddell/ * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**st: Re: RE: Re: Latitude/longitude in spatwmat***From:*"Michael Blasnik" <michael.blasnik@verizon.net>

**References**:**st: Re: Latitude/longitude in spatwmat***From:*"Michael Blasnik" <michael.blasnik@verizon.net>

- Prev by Date:
**st: panel data hausman negative** - Next by Date:
**Re: st: panel data hausman negative** - Previous by thread:
**st: Re: Latitude/longitude in spatwmat** - Next by thread:
**st: Re: RE: Re: Latitude/longitude in spatwmat** - Index(es):

© Copyright 1996–2023 StataCorp LLC | Terms of use | Privacy | Contact us | What's new | Site index |