Open TWF file

The twf file extension is associated with ArcView and used for world coordinates file.

The twf files provide real world coordinate information that allows a corresponding .tif file to be correctly positioned on a map or in a mapping system.

The  twf files are in ASCII editable format that contain six numbers, one on each line. Something like this:

0.7
0 
0 
-0.9
547000.216
789412.471

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 .7 meters wide.
• Line 2: Rotation about the 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 .9 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.

Occasionally the twf files can also have two additional lines, but they are not part of the standard ArcView TWF file format.

• Line 7: Grid zone or Coordinate System.
• Line 8: Datum

Updated: June 13, 2022