Re: MI what is Bonne projection?
Bonne's projection is a pseudoconical equal-area projection. The meridians are represented by concurrent curves, the parallels by concentric arcs of circles. The centre of the projection is defined as the intersection of a straight central meridian with a central parallel of length r0 = R*tan(90-lat0), where lat0 is the latitude of the central parallel. The parallels are correctly spaced along the central meridian and represented in correct length (which gives the projection the equal-area property). Transformation formulae: x = r*sin(T) y = R*cot(lat0) - r*cos(T) where T = R*longit*cos(latit) / r r = R[cot(lat0) - (latit - lat0)] lat0 is the latitude of the central parallel. R is the radius of the generating globe. (setting the equator as central parallel yields sanson's sinusoidal projection). For more information see for example: Canters, F. and H. Decleir, 1989, The world in perspective: a directory of world map projections, John WileySons, Chichester. ___ William De Genst Centre for Cartography and GIS Department of Geography Brussels Free University V.U.B. Pleinlaan 2 B-1050 Brussels BELGIUM Tel: ++ 32-2-629.35.56 Fax: ++ 32-2-629.33.78 http://www.vub.ac.be/DGGF ___ -- To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
RE: MI what is Bonne projection?
Rajeev, I noticed the other answers you have received on the list so far, and they are correct to a point. Within the apparent context of your question about a projection found in an atlas, you have your answer. However, in 19th century Europe and early to middle 20th century Middle East (and most French colonies), the Bonne Projection means something quite different. When working with Geodetic Grid systems it is an ellipsoidal implementation that is NOT the same as using the spherical equations. Geographers will occasionally use ellipsoidal Authalic latitude in thematic applications with the spherical equations. (See the late Prof. Karl Rinner in "Zeitschritt der Vermessungswessen," back in 1932 - I forgot which issue.) The February, 2000 issue of "Photogrammetric Engineering and Remote Sensing" will feature my column on Grids and Datums for the Republic of Madagascar. In that, I discuss the Bonne projection as used in Madagascar and why General Jean Laborde hated it for geodetic work. You can find other countries in past issues of my column at: http://www.asprs.org/resources.html If MI supports it, I would expect it to be the thematic spherical implementation and NOT the special ellipsoidal power series once used for geodetic National Grid systems. Clifford J. Mugnier ([EMAIL PROTECTED]) The Topographic Engineering Laboratory Department of Civil and Environmental Engineering UNIVERSITY OF NEW ORLEANS New Orleans, Louisiana 70148 Voice and Facsimilie: (504) 280-7095 Clifford J. Mugnier ([EMAIL PROTECTED]) The Topographic Engineering Laboratory Department of Civil and Environmental Engineering UNIVERSITY OF NEW ORLEANS New Orleans, Louisiana 70148 Voice and Facsimilie: (504) 280-7095 - On Sunday, 16 January, 2000 10:29 AM, Dr Rajeev saraf [SMTP:[EMAIL PROTECTED]] wrote: Hi: has any body heard of bonne projection. i came across it in an atlas. does mi support it. if so, which option in projection file would do it. -- rajeev saraf File: ATT00032.html -- To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
RE: MI what is Bonne projection?
BONNE Projection is in the family of Conic Projections. It is classified as a pseudoconic, equal area projection. Its central meridian is a straight line, all other meridians are complex curves. Scale is true at the CM and along each parallel. For details, history, usage, formulae, etc., refer to USGS Professional Paper 1395, 'Map Projections - A Working Manual' by John P. Snyder. [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] -Original Message- From: Dr Rajeev saraf [mailto:[EMAIL PROTECTED]] Sent: Sunday, January 16, 2000 11:29 AM To: [EMAIL PROTECTED] Subject: MI what is Bonne projection? Hi: has any body heard of bonne projection. i came across it in an atlas. does mi support it. if so, which option in projection file would do it. -- rajeev saraf -- To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
MI what is Bonne projection?
Hi: has any body heard of bonne projection. i came across it in an atlas. does mi support it. if so, which option in projection file would do it. -- rajeev saraf
