OK Dan,Thanks! I'll give it a try...I agree about all the hoops you need to go through, it wasn't until I started to try making large E-W maps that I noticed the need for it, but now I know about it I have noticed that magically all the roads now run in the bottoms of the valleys!Geoff

Hi there,this tutorial has been working fine for me so far, however, now I'm having trouble interpreting the formula right: N(subset) = N(original) - (Yres * Nrow)W(subset) = W(original) + (Xres * Wcolumn)S(subset) = N(original) - (Yres * Srow)E(subset) = W(original) + (Xres * Ecolumn)In Photohshop I cut out a rectangle of 5000x2000px size,with the left upper edge at x: 2815 and y:1485This is what my .tfw says:28.5000000000000000.00.0-28.500000000000000292353.000000000005370854.0000000000This is my (definitly wrong) interpretition of the formula:N(subset) = 5370854 - (28.5 * 1485) W(subset) = 292353 + (28.5 * 2815) S(subset) = 5370854 - (28.5 * 3485) E(subset) = 292353 + (28.5 * 7815)If somebody could please lead me to the right way, to get reasonable coordinates.

Howdy,your tfw file indicates that your source data are still in the original UTM projection, not the required lat/long. What steps did you take prior to ending up with the tfw file?Cheers, Holger

I found the problem with ERDAS viewfinder.In the dialog box Northings increase upwards.Not downwards... Duh! (It still should crash though)Good thing; I am not a programmer so the GDAL option was not a good one.The confusion comes from my oldfashioned need to work from the bottom left - not the top left (you go in the house before going upstairs)Its working fine now...Geoff

Hi Holger,thanks for your reply.This is what I did so far:1. downloaded band 1, 2, 3.2. opened each in ERDAS ViewFinder3. saved each as TIFF (maybe here is the problem, as a save-as may not mean by default a reprojection???)4. merged those TIFFs in Photoshop.Most likely I did a mistake doing step 3, the reprojection.Could you plead explain how a reprojection is done?Is this eventl. in the save-as dialog checking 'change output projection'?Looks like you already led me there!If so, another question arises, what is there the difference between projection for Germany and Germany_85_Potsdam?