[Freegis-list] TFW format
freegis at pbox.cz
Thu Oct 6 16:44:45 CEST 2005
Yes, i found this description too, but how can i work with these values?
Bill Thoen wrote:
> On Thu, Oct 06, 2005 at 04:12:01PM +0200, Petr wrote:
>>i need help with tfw format. I have tiff image and tfw file with
>>I searched internet and not found any information about using of this map.
> Googling on "tfw format" I found the following on
> 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.
> Also, the GeoTIFF format spec can be found at:
>>I need transform standard GPS coordinate (eg.: 50d04m55sN 14d26m03sE) to
>>pixel coordinate in my map (eg.: 256px,414px aproximately) and backwards.
> Unfortunately, knowing the TFW format won't help you with converting your
> GPS coordinate. The TFW file doesn't contain coordinate system information,
> so you don't know the projection method, datum, etc. But once you convert
> it into the same system used in your TIFF file, the tfw parameters can be
> used to locate it on your image accurately.
> - Bill Thoen
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> Freegis-list at intevation.de
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