Why is TileMapLayer Cell 0,0 not equal to origin in isometric layout?

Godot Version

4.4

Question

I have the following setup. The white rect indicates 0,0 where the TileMapLayer is positioned

I’m surprised to discover that cell (0,-1) is at local position (0,0) and not cell (0,0). I thouht I had an error in my generator that my tiles where offset, but it turns out to be a quirk of the TileMapLayer, which seems counterintuitive. Or is there something wrong with my setup?

Having learned that, i’ll now offset my isometric layer positions by half a tile. But I can’t stop wondering, if I have some more general error in my config or whether i’m just being pedantic here.

I found a lot of posts related to whether the local position would be centered, top left or somewhere else. This has nothing to do with my question. I’m really just confused about which cell is (0,0)

Maybe because the tile size is not a square? Or maybe not (I haven’t tried using isometric tiles).