I have a large poster. But I only have access to small A4 printers. First I have gone by the way of Gimp. Using the guillotine to break a large image into smaller pieces. Quite a pain. Than I have discovered PosteRazor. Compared with Gimp, this is a walk in the park. In the end I get a PDF with the pages. But I still have to guess the page position from the printing order. I have no guides for cutting and none for sticking the pages together. It is faster, yet still a large part of the work done blindly. The only help is that small mistakes are harder to spot on larger posters.
Now I have a new idea. Scribus has everything I need. Guides. And marks. But how do I feed Scribus a large image and get the multi-page document that has all the markers to assemble the final poster on the given support media? Cheers!