Not the person you're responding to, but I also think I have a substantial degree of aphantasia (my "mind images" are quite weak and inconcrete) after reading about the subject in the past. Interesting exercise.
If you ask me to explain that, I do think in a kind of abstract first-person 3D map of the street and my home, which can be pretty accurate in terms of scale, angles, etc. and it is helpful enough to accurately perform the task at hand of describing how to find the fork. But I can't really say I picture it in any meaningful way. Things have no color, but I can't say that they are black and white either, they are just the concept of an object of a given shape occupying a given space. When I mentally go to my home's door, I can stop and think about what color the door is (only with one object at a time) but this feels more like assigning the concept of whiteness to the abstract idea of the door being there, than like evoking an image of the door.
If you ask me to explain that, I do think in a kind of abstract first-person 3D map of the street and my home, which can be pretty accurate in terms of scale, angles, etc. and it is helpful enough to accurately perform the task at hand of describing how to find the fork. But I can't really say I picture it in any meaningful way. Things have no color, but I can't say that they are black and white either, they are just the concept of an object of a given shape occupying a given space. When I mentally go to my home's door, I can stop and think about what color the door is (only with one object at a time) but this feels more like assigning the concept of whiteness to the abstract idea of the door being there, than like evoking an image of the door.