1. A method for generating a tree map, the method comprising: obtaining, with a processing device, node information of a plurality of nodes to be processed, the plurality of nodes to be processed being sub-nodes sharing a same parent node and the node information comprising at least sizes of the nodes; determining from the plurality of nodes a plurality of candidate nodes whose sizes are less than a threshold size; determining super node including the plurality of candidate nodes based on the node information of the determined plurality of candidate nodes, a screen size, and the threshold size, such that when displaying in a zooming-in mode the super node on the screen, all candidate nodes in the super node are displayed at display sizes not less than the threshold size, wherein determining the super node comprises: ranking the candidate nodes according to the node sizes; dividing the ranked candidate nodes into a plurality of candidate node subjects; judging whether all nodes of each candidate node subset can be identified by zooming-in one time, and dividing unqualified candidate node subsets until all nodes of all node sets can be identified by zooming-in one time; and determining the super node according to the divided candidate node subsets; and determining data required for displaying the tree map based on the super node.