feature-based queries
e.g., what is at location x?
not good if looking for particular feature as have to examine every block or location asking "Are you the one I am looking for?
Pyramid is good for feature-based queries
Does wheat exist in region x?
-if wheat does not appear at the root node,then impossible to find it in the rest of the structure and the search can cease
-report all crops in region x--just look at the root
Select all location all wheat is grown
-only descend a node if there is a possibility that wheat is in one of its four sons --implies little wested work
Ex.truncate pyramid where 4 identically- colours son are merged
Implies