Hi Chris,
saving an ECW out to a lossless-TIFF will result in an image of comparable (or likely identical) quality to the ECW file itself. If you save it to a lossy-TIFF (JPEG lossy compression in the TIFF), you will probably get a small amount of quality loss. A quick way to see the difference would be to do a difference forumla on the ECW & TIFF and check the histograms. Regards -- Simon ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^ Simon Cope, : e-mail: [EMAIL PROTECTED] Chief Technical Officer - : WWW: http://www.ermapper.com Internet Technologies, : Int'l Phone: +61 8 9388 2900 Earth Resource Mapping Pty Ltd, : Int'l Fax: +61 8 9388 2901 Level 2, 87 Colin St, West Perth. : Australia Phone: (08) 9388 2900 Western Australia 6005 : Australia Fax: (08) 9388 2901 Q: 1.2TB (1,200GB) Image over the Internet? A: Image Web Server! http://www.earthetc.com > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Brown, Christopher > (HI) > Sent: Monday, 27 May 2002 9:05 AM > To: '[EMAIL PROTECTED]' > Subject: ECW back to tif? > > > I have some ECW files of aerial orthophotos which were originally > tif images > but no longer have access to the original tif's and wish to use > these images > in a mobile mapping application on Compaq Ipaq hardware. The application > currently does not have the facilities built in to display ECW format so I > need to save the ECW back to tif. The application is MapX Mobile from > MapInfo Inc. > I know I can open the images up and save them as tif's in ERMapper but was > wondering if anyone would know if there has been any information posted to > the web about the implications of reversing ECW compressed imagery ie > quality and loss etc? > Thanks and regards > Chris > > Chris Brown - Cartographer > Resources Planning, Hamersley Iron P/L > Tel. +61 8 9327 2176 > Fax. +61 8 9327 2478 > mailto:[EMAIL PROTECTED] > > > > ---------------------------------------------- > This email (including all attachments) may be confidential. If > you are not > the intended recipient, you must not use the information contained in it. > If you have received this email in error, please delete the email > and notify > the sender. > ----------------------------------------------------------- > > To make changes to your subscription, please visit our website, > http://www.ermapper.com/technicl/ermapperl/index.htm > > ----------------------------------------------------------- To make changes to your subscription, please visit our website, http://www.ermapper.com/technicl/ermapperl/index.htm
