While reading about OSPF, I stumbled upon the following text:
An OSPF area hides the topology from another area but allows for the networks to be visible in other areas within the OSPF domain.
If a topology change occurs (link flap or additional network added) within an area, all routers in the same OSPF area calculate the SPF tree again. Routers outside of that area do not calculate the full SPF tree again but will perform a partial SPF calculation if the metrics have changed or a prefix is removed.
Could someone please explain what view of an area is available to router outside the area and how partial calculation is enough for router outside that area.
Okay, Finally I found the answer:
Lets say we have two areas Area0 and Area1234.
In that case Collection of (Type1 + Type2) LSAs that belong to particular network of Area1234 become 1 single summary LSA for Area0.
Summary LSA does not have any topology information, it only contain information that which ABR router to follow for a particular network that lies outside my Area.