I'm still having trouble with this problem and thought I would repost it during a working day instead of a Saturday night! Any help gratefully received!!
Original post I have a Main table of polygons and an imported DWG of lines. Both are in BNG (British National Grid) however the imported DWG is off by about 2000 meters AND rotated with respect to the MAIN table. I have done some reading of the archived MI-L discussion of affine transformations and i recon that's what i need to move and rotate the DXF table to overlay the Main table. I got the coordinates of 2 common points (below) from the tables and used them in Neil Moseley's Affine Calculator at http://www.geodata.biz/prod03.html ID Description X Y 1 Main 1 571940.64 285584.97 2 DXF 1 574847.11 285919.58 3 Main 2 569262.67 284983.29 4 DXF 2 572149.49 285397.21 The results were as below: A= 0.011274564226 B= -1.011407926757 C= 857241.63094145 D= 1.011407926757 E= 0.011274564226 F= -295765.56301657 So using those results I put a affine clause in the mif file as below and imported it. Version 300 Charset "WindowsLatin1" Delimiter "," CoordSys Earth Projection 8, 79, 7, -2, 49, 0.9996012717, 400000, -100000 Affine units "m", 0.011274564226, -1.011407926757, 857241.63094145, 1.011407926757, 0.011274564226, -295765.56301657 Columns 1 autocad_elevation Decimal(2, 0) Data The DXF file was moved and rotated but nowhere near where it should be. I don't think I am far away from getting this right but could someone please point out where I'm going wrong please - my head is beginning to spin trying to understand projections, datum's etc... Thanks Jim Wilson --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.656 / Virus Database: 421 - Release Date: 09-Apr-04 --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 11464
