careful of the difference in e and a
a settlement, settled by ..... Eποικια
colony/colonize = Aποικια

I think that because of the context, namely the inhabited area of a still predominantly rural area / community outside Thessaloniki, perhaps a distinction is being made between the land dedicated to agriculture and the zones given over (whether as part of an urban development plan or otherwise) to settlements - in this context, therefore, I would propose 'developed area', in order to distinguish the zones given over to rural / semi-urban settlements from the surrounding/ interspersed patches of farmland.