Before you start digging, consider a couple of possibilities: Does the pantomime Madagascar appear "rotated" from the way it should appear? If so, your azimuth is probably wrong. The fact that the azimuth is the same as the origin latitude raises a red flag for me.
Does it appear "bigger" or "smaller" than it should? If so, then depending on who made the paper map data and when, perhaps the units are not meters (gasp). This is the most common reason for such a displacement here in the US. You might play with the false easting and northing to force it into the right general area, just to see if it's rotated or resized. If it's "warped" then you might have the origin wrong, or even the projection algorithm. Or perhaps it's not Madagascar after all, but the mythical island of Taprobane.... ;) Hope this helps Spencer ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Lawley, Russell S Sent: Thursday, March 23, 2006 4:02 AM To: MapInfo-L (E-mail) Subject: [MI-L] projection woes for madagascar. Hi, I am trying to bring in some geology data for Madagascar, as usual the data has been captured from a paper map via a non-projection gis (u kno who). so whilst i have map coordinates that 'make sense' i actually only have a map in Non-earth projection. From the original paper maps i can see i am supposed to be using a Laborde projection, and a fabulous article by Clifford Munier provides all the data (i think) that my paper maps did not..but i am now stuck...because although i appear to have all the data i need to write my own projection, i am obviously getting it all wrong because my version of madagascar is sitting about 1 degree south of the equator and about 10 degrees further east than it should be,,,,, here are the projection input data i am using..I suspect i have misread something somewhere, but at 2:20am this morning i was all for taking a spade to madagascar and digging it all up to move it to 54e, 1s.. projection oblique Mercator (hotine) datum Tananarive_1925 spheroid international 1924 Origin long 46.43722917 Origin Latt -18.9 Azimuth 18.9 scale factor 0.9995 false east 400000 false north 800000 units m. mapinfo prj file entry = "Russells Botched Laborde", 7, 147, 8, 46.43722917, -18.9, 18.9, 0.9995, 400000, 800000 Has anyone got any ideas as to what i have missed? regards r ********************************************************************* This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. ********************************************************************* _______________________________________________ MapInfo-L mailing list [email protected] http://www.directionsmag.com/mailman/listinfo/mapinfo-l
