 |
|
 |
Home Page : File Types : dot T : .tfw
|
|
|
|
|
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 an image has its origin in the top left corner but for Northings and Eastings the origin would be towards 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.
Relevant links:
Try Free Performance Scan to help optimise memory, CPU and other PC settings.
Can you add to this? Do you know of any applications not already listed that will open or work with this type of file? Can you contribute any additional file format information? Please report any errors or omissions by e-mail to feedback@cryer.co.uk.
© Copyright 2004-2008, A B Cryer, All Rights Reserved.