How it works. You pick a grid — say 2×2 (4 sheets) or 3×3 (9 sheets) — and a sheet format. The tool divides the page into fragments and adds an overlap to each: a strip of the neighbouring content, 10 mm by default. Sheets are glued overlapping, so seams show no white gaps even if the printer clips the edges slightly. Sheet orientation is chosen automatically to match each fragment's proportions.
The key difference from 'screenshotting in pieces' is quality. Fragments are cut from the PDF without rasterization: vector drawing lines and text stay vector and print at the printer's full resolution. On a zoning map this is critical — thin zone borders and small labels don't dissolve into pixel mush when enlarged.
Practical printing and assembly tips. Print at 100% scale (not 'fit to page' — otherwise the overlaps stop lining up). Assemble row by row: glue sheets into rows first, then join the rows, aligning content inside the overlap zone. For long-lived posters (an evacuation scheme, a wall map) it is neater to trim the overlap of one neighbouring sheet along a line and glue edge-to-edge onto a backing board.