What a player saw
The armouries of Pendragon, Sandy Shores and Pendleton sell Scroll IV from the start of a new game. Buy it and use it, and instead of a page of writing you get a full-screen picture of the island of Scandor with its forests, hills, lakes and roads, and under it the words "Geography of Scandor".
Why a scroll can be a picture
The game keeps the scrolls' pages as numbered files on the disk, and it finds a scroll's pages from the scroll's own number, with no list in between. Scroll IV opens page 6, and page 6 is not writing but a picture. The reader has a special case for it. Page 6 is loaded as an image and shown on its own, with no frame around it.
Why I thought it was never shown
For a while my notes listed the map among the things the game planned and never used. That was wrong. When I bought Scroll IV in the running 1987 game and read it, the map filled the screen, and the game's own data agrees. The armouries of the first three towns stock it in every new game.
The map borrows its colours
The picture file carries its own 16 colours, and the reader loads them and never uses them, so the map is shown in whatever colours are on the screen at the time. In the picture above it was read on the map outside Pendragon. I have tested this by running the original code, but not yet seen it in the 1987 game, and which colours a reader would see in a dungeon, or in a town of the Plane of Dark or the Underworld, is still open.
The map turns up in a trap
In three dungeons one kind of trap reads its message from an empty slot, so the line at the bottom of the screen stays blank. The empty slot points into the memory where scrolls are read. A page of writing fills only the start of that memory, but the map fills most of it, so once anyone in the party has read Scroll IV, that trap prints seven odd symbols, a scrap of the map picture. I saw it happen in the 1987 game in the emulator. Before the map has been read the line stays blank there; whether a real Amiga ever shows something else is still open.