.tfw file extension
- ArcView world coordinates file. Also commonly known as a Tiff World
A .tfw file is used to georeference a .tif file. The .tfw file provides real world coordinate information that allows a corresponding .tif file to be correctly positioned on a map or in a mapping system.
A .tfw file is an ASCII text editable file that contains six numbers, one on each line. For example:
0.6 0 0 -0.6 355000.317 459999.682
Each line provides the following information:
Line 1: x-scale. This is the horizontal distance in meters represented by each pixel. So in the above example each pixel is .6 meters wide. Line 2: Rotation about y axis. Line 3: Rotation about x axis. Line 4: y-scale This is the vertical distance in meters represented by each pixel. So in the above example each pixel is .6 meters tall. Normally negative, because whilst an image has its origin in the top left corner, for Northings and Eastings the origin is normally considered to be the bottom left corner - hence why the scale is normally negative. Line 5: x-reference point. This is the horizontal coordinate (or Easting) of the center of the top left pixel. Line 6: y-reference point. This is the vertical coordinate (or Northing) of the center of the top left pixel.
Sometimes a .tfw file will have two additional lines:
Line 7: Grid zone or Coordinate System. Line 8: Datum
These additional lines are not part of the ArcView TFW format.
Can you add to this? Do you know of any applications not already listed which will work with .tfw files, view .tfw files or open .tfw files? Are you able to contribute any additional reference information or file format information about .tfw files or have you spotted any errors or omissions? If so please let us know by emailing us at firstname.lastname@example.org - Thank you.