Information about the .tfw (tfw) file type

Below is all the information we have available on file about the .tfw (tfw) file type.

.tfw
ArcView world coordinates file. Also commonly known as a Tiff World File.

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.

cf .jgw.

Where this is available we would like to include file format information on .tfw files, as well as information on how to view or open files of type .tfw. If you know of any information which we have missed then please let us know.