Why grocery stores rearrange aisles that regular customers already know

The local supermarket moved the pasta, coffee and breakfast cereal to completely different aisles. I assume there was a business reason, but regular customers now wander around looking mildly betrayed. Is rearranging a store mainly about exposing shoppers to products they wouldn't otherwise pass, improving inventory flow, or negotiating shelf space with brands? Has anyone worked in retail planning and seen the real decision process?