Laws are often cascaded as well. Specifically in this case, Spain is subdivided into Comunidades Autonomas - each have their own elected parliament. And inside those are cities with their own local laws.
So while this project does track laws, is there any facility to determine which laws from which bodies are relevant to a specific activity in a specific location?
I may be wrong, but I think autonomous community legislation is not published in the BOE itself (the Official State Gazette), but rather in each of their corresponding official gazettes (e.g. DOGC for Catalonia, BOCM for Madrid, BOA for Aragon, BOJA for Andalusia, etc.).
yes: Comunidades Autonomas can only defined laws as "permitted" by the central government under a Estatuto de Autonomia (Autonomy statute? not good with legal jargon), which is effectively a law of its own. So at the central level the law says "in this particularly region, matters of education are dealt with regionally", and then that's when regional laws apply. Same from local laws. In essence, all laws emanate from the central government, but the central government decides to delegate some areas; technically, they could always take it back.
> And inside those are cities with their own local laws.
No, cities don't have their own laws, but the autonomous communities do have some influence in some laws and regulations (not all), like the amount of income tax you have to pay and so on. But cities within the autonomous communities don't have their own laws.