From wsanford@wsanford.com Sun Aug 28 11:36:37 2005 Date: Mon, 23 Jun 2003 20:31:59 -0400 (EDT) From: Walter Sanford To: Walter Sanford Subject: Miles/Kilometers to Degrees/Minutes of Lat/Lon > Personal communication, Dr. Robert Kellogg, 18 JUN 2003 The distance of one degree in km at any latitude is d = 111*cos(lat) e.g., 50 deg N lat.: cos(50) = 0.642788 d = 111*(0.642788) = 71.349468 km [WBS] or d = 69*cos(lat) = 69*(0.642788) = 44.352372 mi e.g., 39degN: cos(39) = 0.777146 d = 111*(0.777146) = 86.263206 km d = 69*(0.777146) = 53.623074 mi == > Waugh, pp. 198-199 C ._____.A | 11 mi | 12 mi| | | | . B "... convert...mileages to degrees or minutes of latitude and longitude." "Each mile of noth-south direction is the equivalent of about 0.868 min. of latitude, ...." "The adjustment for longitude is not quite so simple. The east-west mileage corresponding to one min. of longitude varies with the latitude, and our adjustment factor is 0.868/cos(lat)." Example: Altoona, PA = 40deg30min N lat correction factor = 0.868/cos(40deg30min) 0.868/0.760 = 1.14 29 mi. x 1.14 = ~33 min. of lon. ================================================================= Walter Sanford, Director Carl Sandburg Middle School Center for Sky Awareness 8428 Fort Hunt Road Sandburg Planetarium Alexandria, VA 22308 Fairfax County Public Schools Work: 703-799-6169 -6197 (fax) E-mail: wsanford@wsanford.com Home: 703-765-9392 AMS Project ATMOSPHERE Atmospheric Education Resource Agent SCSA, Geosystems, & Camp T-Equity - URL: http://www.wsanford.com/ =================================================================