1999.09.11 06:01 "Re: .tfw format", by James McMullen
This is surprisingly obscure information, considering how widely used
A web search turned up only a dead link into ESRI; no doubt the official
definition is there somewhere. AFAIK, TFW says nothing about units or
projection; you just have to know that a particular file is, say, NAD27
California State Plane Zone 6.
The following is from the good folks at ER Mapper, with whom I have no
Q34. Can ER Mapper use TIFF World files (TFW)?"
A. The TFW file was created to give spatial location to the massive
imagery that is traded around in TIFF, which does not carry any
information on it's own.
In a directory structure, the TFW file will have the same name as the TIFF
it is referencing as in this example:
The TFW structure is extemely simple. It is a 6 line file that can be
opened up and read in any text editor such as WordPad or Notepad in Windows.
A sample TFW file opened up would look like:
Line 1 - Cell size in the "X" direction
Line 2 - Insertion point in the "X" direction
Line 3 - Insertion point in the "Y" direction
Line 4 - Cell size in the "Y" direction
Line 5 - Easting value of insertion point "X"
Line 6 - Northing value of insertion point "Y"
Note that sign on line 4 will tell you if the insertion point is the upper left
or lower left corner. A positive means the "Y" values are increasing upwards and
therefore, the registration must be starting at the bottom or lower corner.
Vice-versa for a negative sign.