How to prevent switching to "world" map?

The zoom autoload feature is generally useful, but the tendency to switch right out to the world map seems to be something few would ever want.

Is there a way of preventing this?

To answer my own question, I suppose one simply needs to make sure you have some intermediate level maps stored. Still, I feel it would be better if it tended to bias slightly more towards zooming out of the higher detail view.

In my experience, the world view comes in when no other mapping data is available for a given location. If I'm using an online map (i.e. OSM), that only happens if my phone is offline. In other words, there's no relevant data to zoom out of.

I think that's right; I've just fairly often encountered it by accident, and feel like it might be better if it was more biased towards downscaling the view of a high resolution layer if that's all that's available. Really though, the simple solution is to just download a few low resolution layers so that there's reduced risk of hitting something for which there's no coverage; it's not like they take up much space.

I feel a bit stupid for not realising that before, but still think it's a slight usability niggle. It's sometimes quite hard to zoom back in on a sensible map once it goes out to the world one - normally tends to happen at a slightly awkward moment.

Exactly. The maps take so little space that you can afford to be generous.

Try this setting: Go to Settings --> Maps --> Maps AutoLoad and choose 'Never'.
Joachim