How to generate TFW files for a list of images?

Question

I have a few digital images that are not georeferenced. E.g.:

Img01.tif  
Img02.tif  
...
Img99.tif  

On the other hand, I have a text file, which contains georeferencing information for these images. E.g., I have a file c:\tfws\list.txt which contains the following information:

Img01.tfw 0.25 0 0 - 0.25 456258,125 4569852,125  
Img02.tfw 0.25 0 0 - 0.25 456586,125 4570001,125   
Img03.tfw 0.25 0 0 - 0.25 456952,125 4570300,125  
...
Img99.tfw 0.25 0 0 - 0.25 458412,125 4575123,125  

I need to generate a TFW file for each image in the text file. E.g. create a file named C:\tfws\img??.tfw containing the following information:

0.25  
0  
0  
-0.25  
456258,125  
4569852,125  

Does anyone know of a tool able to generate these TFW files automatically?

Answer 1

It isn't nice code, but for your specific circumstance, here is some python that should save typing them out by hand:

f = open('list.txt', 'r')
lines = f.readlines()
for line in lines:
    lineparts = line.split(' ')
    outfile = open(lineparts[0], 'w')
    for i in range(1, 4):
        outfile.write(lineparts[i] + '\n')
    outfile.write(lineparts[4] + lineparts[5] + '\n')
    for i in range(6, 8):
        outfile.write(lineparts[i] + '\n')

(real code would sanity check, but I assume you can check the results)

Answer 2

AWK is perhaps the most effective tool for such text conversion (although if you're familiar with Perl you might prefer it, out of habit): it was designed for exactly this kind of one-off quick reformatting work.

Here is the full AWK code to perform the requested operation on the input specified:

BEGIN {OFS="\n"}
{print $2, $3, $4, $5 $6, $7, $8 > $1}

(The absence of a comma between $5 and $6 is no misprint: it concatenates the minus sign - with the following value 0.25.)

This can be typed directly into AWK, but it's better to put it into a file called, say, tfw.awk. It would then be invoked from a command line prompt like

tfw list.txt

or

awk -f tfw.awk list.txt

(if the system environment has not been set up to recognize .awk files as executable).

It will execute instantaneously, leaving behind the specified files (and overwriting them if they already exist).

Every Unix system comes with a copy of AWK and there is a free GNU version for Windows. I just downloaded the GNU distribution and ran it on a Windows 64 workstation; it works fine.