Method and apparatus for logical zooming of a directed graph

• US 6,437,799 B1
• Filed: 12/06/1999
• Issued: 08/20/2002
• Est. Priority Date: 03/03/1999
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shinomi, Hideaki
• Primary Examiner(s): Luu, Matthew
• Assistant Examiner(s): Havan, Thu-Thao
• Application Number:
  US09/452,924
• Time in Patent Office: 988 Days
• Field of Search: 345/666, 345/667, 345/670, 345/671, 345/788, 345/815, 345/853, 345/854, 345/855, 345/645, 707/1, 707/104, 707/104.1, 707/2, 707/6, 707/7
• US Class Current: 345/666
• CPC Class Codes: G06T 11/206 Drawing of charts or graphs
• CPC Class Codes: Y10S 707/99936 Pattern matching access

Abstract

A directed graph is logically zoomed, whereby the appearance of a node directly related to a target node can be exaggerated and the structure of an entire graph can be readily understood. A directed graph is used in which hierarchical nodes are connected by arcs. In the directed graph, a node that has a predetermined logical relationship with a selected node is displayed differently than are the other nodes. For example, a displayed node logically near the selected node is large, while a displayed node logically distant is small, or the node logically near the selected node is moved closer to the selected node.

Claims

1. A logical zooming method for a directed graph, in which a plurality of hierarchical nodes are connected by arcs, comprising a step of:

displaying said hierarchical nodes utilizing a plurality of hierarchy levels, each one of said hierarchical nodes being displayed at a location in said graph which corresponds to one of said hierarchy levels;

logically zooming in on a specified one of said hierarchical nodes; and

displaying said specified one of said hierarchical nodes and ones of said hierarchical nodes that are logically near said specified one of said hierarchical nodes differently from other ones of said hierarchical nodes, each one of said hierarchical nodes continuing to be displayed at a location in said graph which corresponds to said one of said hierarchy levels, wherein after said step of logically zooming, each one of said hierarchical nodes remains displayed in a same one of said hierarchy levels in which said one of said hierarchical nodes was displayed prior to said step of logically zooming.

2. The logical zooming method according to claim 1, whereby said specific node and a displayed node logically near said specific node are enlarged, and all displayed nodes logically distant from said specific node are reduced in size.

3. The logical zooming method according to claim 2, whereby, when a hierarchy level of said specific node is n, distances between hierarchy levels n and n+1 and between hierarchy levels n and n−

1 are set in order to allow a name of said specific node and names of nodes, connected by arcs, for which said specific node is a start point or an end point to be clearly readable and whereby sizes of other nodes are reduced so that all nodes can fit on a screen.

4. The logical zooming method according to claim 1, whereby at each hierarchy level n+1 and n−

1 a transverse arrangement of nodes is changed, so that relative to a hierarchy level n of said specific node, a node for which said specific node is a start point or an end point is positioned nearer to specific node.

5. The logical zooming method according to claim 1, whereby, when an arc connecting said specific node and a node having said predetermined logical relationship with said specific node is a dummy node that extends across a hierarchy, said dummy node is defined as a display dummy node for displaying, in said hierarchy, said node having said predetermined logical relationship with said selected specific node.

6. The method according to claim 1, further comprising the steps of:

displaying said hierarchical nodes utilizing said plurality of hierarchy levels, each one of said hierarchical nodes being displayed at a y-coordinate location in said graph which corresponds to one of said hierarchy levels; and

displaying said one of said hierarchical nodes and ones of said hierarchical nodes that are logically near said one of said hierarchical nodes differently from other ones of said hierarchical nodes, each one of said hierarchical nodes continuing to be displayed at said y-coordinate after said step of logically zooming.

7. The method according to claim 1, further comprising the step of displaying said hierarchical nodes utilizing said plurality of hierarchy levels wherein one of said hierarchy levels associated with one of said hierarchical nodes can be determined by viewing said graph.

8. A logical zooming apparatus for a directed graph, in which a plurality of hierarchical nodes are connected by arcs, comprising:

an input device for entering data;

a display device for displaying the directed graph;

an arc start/end input unit for reading node information at start points and end points of all arcs to be processed;

a graph information extractor for, based on start/end point information for all the arcs, internally generating graph information in which said nodes are linked together by said arcs;

a coordinate calculator for determining x-y coordinates for each of said nodes displayed on a screen of said display device;

a graph information storage unit for storing information for said directed graph for said display device;

means for logically zooming in on a specified one of said hierarchical nodes; and

means for displaying said specified one of said hierarchical nodes and ones of said hierarchical nodes that are logically near said specified one of said hierarchical nodes differently from other ones of said hierarchical nodes, each one of said hierarchical nodes continuing to be displayed at a location in said graph which corresponds to said one of said hierarchy levels, wherein after said step of logically zooming, each one of said hierarchical nodes remains displayed in a same one of said hierarchy levels in which said one of said hierarchical nodes was displayed prior to said step of logically zooming.

9. The apparatus according to claim 8, further comprising:

means for displaying said hierarchical nodes utilizing said plurality of hierarchy levels, each one of said hierarchical nodes being displayed at a y-coordinate location in said graph which corresponds to one of said hierarchy levels; and

means for displaying said one of said hierarchical nodes and ones of said hierarchical nodes that are logically near said one of said hierarchical nodes differently from other ones of said hierarchical nodes, each one of said hierarchical nodes continuing to be displayed at said y-coordinate after said step of logically zooming.

10. The apparatus according to claim 8, further comprising means for displaying said hierarchical nodes utilizing said plurality of hierarchy levels wherein one of said hierarchy levels associated with one of said hierarchical nodes can be determined by viewing said graph.

11. The logical zooming method according to claim 8, whereby said specific node and a displayed node logically near said specific node are enlarged, and all displayed nodes logically distant from said specific node are reduced in size.

12. A computer program product recorded on computer readable medium for logically zooming a directed graph in which a plurality of hierarchical nodes are connected by arcs, comprising:

computer readable means for entering data;

computer readable means for displaying the directed graph;

computer readable means for reading node information at start points and end points of all arcs to be process;

computer readable means for internally generating graph information in which said nodes are linked together by said arcs;

computer readable means for determining x-y coordinates for each of said nodes displayed on screen of a display device;

computer readable means for storing information for said directed graph for said display device;

instruction means for logically zooming in on a specified one of said hierarchical nodes; and

instruction means for displaying said specified one of said hierarchical nodes and ones of said hierarchical nodes that are logically near said specified one of said hierarchical nodes differently from other ones of said hierarchical nodes, each one of said hierarchical nodes continuing to be displayed at a location in said graph which corresponds to said one of said hierarchy levels, wherein after said step of logically zooming, each one of said hierarchical nodes remains displayed in a same one of said hierarchy levels in which said one of said hierarchical nodes was displayed prior to said step of logically zooming.

13. The product according to claim 12, further comprising:

instruction means for displaying said hierarchical nodes utilizing said plurality of hierarchy levels, each one of said hierarchical nodes being displayed at a y-coordinate location in said graph which corresponds to one of said hierarchy levels; and

instruction means for displaying said one of said hierarchical nodes and ones of said hierarchical nodes that are logically near said one of said hierarchical nodes differently from other ones of said hierarchical nodes, each one of said hierarchical nodes continuing to be displayed at said y-coordinate after said step of logically zooming.

14. The product according to claim 12, further comprising instruction means for displaying said hierarchical nodes utilizing said plurality of hierarchy levels wherein one of said hierarchy levels associated w,with one of said hierarchical nodes can be determined by viewing said graph.

15. The logical zooming method according to claim 12, whereby said specific node and a displayed node logically near said specific node are enlarged, and all displayed nodes logically distant from said specific node are reduced in size.