In this paper, we will introduce a method of dynamically retrieving zones containing clustered objects satisfying the conditions given by the user and computing objects with the most distinct characteristics which we call landmarks. These operations would help the user retrieve and browse the spatial data dynamically in the following ways. Determining the zones would provide one with a general information of the spatial distribution of the objects one wishes to see, thus freeing one from unnecessary browsing. Computing the landmarks would provide one with descriptive information on the zones which were dynamically retrieved. We will discuss algebraic operations for zone retrieval and computational expressions for describing landmarks.