Hi Neal, My understanding is that the TFW et.al. defines an affine transformation on an (any) implicit projection:
groundX = a0 + a1 * pixelX + a2 * pixelY groundY = b0 + b1 * pixelX + b2 * pixelY The TFW file stores these 6 parameters this way: a1 b1 a2 b2 a0 b0 For an axis parallel image, b1 and a2 are 0, and a1 and a1 and b2 are pixel sizes in X and Y resp. (a0,b0) are the upper-left corner of image, which is why b2 is usually negative as ground Y is normally defined to be positive upwards. It should be fairly easy to transform a TFW to TAB, just applying the above formula appropriately. The other direction is a bit more tricky since MapInfo handles more than 3 control points. Best regards/Med venlig hilsen Lars V. Nielsen GisPro, Denmark http://www.gispro.dk/ http://hjem.get2net.dk/lars-online/ WGS84: 10.20'40"E 55.20'20"N > ----- Original Message ----- > From: "Neil Havermale" <[EMAIL PROTECTED]> > To: "Mapinfo-L (E-mail)" <[EMAIL PROTECTED]>; "Gislist > (E-mail)" <[EMAIL PROTECTED]> > Sent: Wednesday, January 01, 2003 12:02 AM > Subject: GISList: JPEG (JPG) and JPEGW (JPW) > > > > I have a number of USDA/NRCS aerial images. For each JPG image there is a > > companion file with the extension of JPW that includes what seems to be a > > UTM meters reference following UL and LR latice values for the image > > matix(?). Any help with importation without re-registration? The images > > are from Minnesota. Anyone with insight on this? > > > > 2.000000 > > 0.000000 > > 0.000000 > > -2.000000 > > 410000.000000 > > 4932400.000000 > > > > Also FYI, the NRCS has essentially 100 percent of most counties covered > with > > 1:600 B&W as well as color imagery used to establish farm MU (mapping > units) > > for various USDA compliance and other programs. It looks like in the MN > > case, they are providing these images as JPEGs free. Most counties likely > > also have these registered images certainly as scanable images or as > > binaries. > > > > Thanks, > > MidnIght Mapper > > aka neil > > PS Happy New Year - My resolutions is to survive one more year of this > > administration on the hope something good comes along.... > > > > > > > > To unsubscribe, write to [EMAIL PROTECTED] > > ________________________________________________________________________ > > GeoCommunity GeoBids - less than $1 per day! > > Get Access to the latest GIS & Geospatial Industry RFPs and bids > > http://www.geobids.com > > > > Setup a GeoCommunity Account and have access to > > the GISDataDepot DRG & DOQQ Catalog > > http://www.geocomm.com/login.php > > > > > --------------------------------------------------------------------- > List hosting provided by Directions Magazine | www.directionsmag.com | > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > Message number: 4726 > --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 4732
