CharGer is a conceptual graph (CG) visual editor written in Java. It is intended for researchers and practitioners who want to create and edit graphs for CG knowledge bases. CharGer supports most CG features, including actors, contexts, and interchange.
Added are ISO CGIF export/viewing and a link to the sourceforge download page.
These features are currently supported (as of version v3.6 2008-08-06):
• Save and retrieve graphs from files, in an XML format called CGX (see Appendix). These are ordinary XML text files and are portable across all platforms.
• Save and retrieve graphs from earlier CharGer files, in a proprietary (i.e., non-standard) text format. These graphs have the extension .cg and are portable across all platforms.
• Save graphs in Conceptual Graph Interchange Format (CGIF) standard interchange format conforming to ISO/IEC 24707:2007 Annex B. These graphs have the extension .cgif and are portable across all platforms.
• Display a graph's CGIF version or a graph's (crude) natural language paraphrase, copy it to the clipboard as text, or save it to a text file.
• Save a graph in some graphics formats: EPS, PDF, SVG, EMF, GIF and PNG
• Copy/paste of graphs using an internal clipboard.
• Copy and paste from CharGer to other applications.
• Any number of graph windows may be opened for editing.
• Concepts, relations and actors are all supported for editing.
• Type and relation hierarchies may be edited and saved the same way as a graph, and may be intermixed on the same sheet of assertion.
• Graphs may be labeled as to their intent (e.g., query, definition, etc.)
• Contexts are supported, including arbitrary nesting. Negated contexts (“cuts”) are also supported.
• Save-before-close to prevent losing a graph, and other modifications to prevent losing data.
• Zoom in and out on a graph’s view
• Unlimited undo/redo for editing changes (limited only by available system memory)
• Portability to all major platforms (i.e., as portable as Java based on JDK 1.4.2)
• Activation of some built-in actors, including several primitive ones for arithmetic and elementary operations, with an optional “animation” to show their operation.
• Database access through actors, although restricted to tab-separated text file “databases” at present.
• User-written (in Java) actor plug-ins with a published plug-in interface.
• Capability to automatically create a skeleton graph from a database suitable for providing database semantics.
• Keystrokes to move and explicitly resize graph objects and contexts
• Keystrokes to switch editing tools.
• A natural language paraphrase feature, to paraphrase a graph in English (other languages on the way)
• Ability to set user preferences and save them between sessions.
• Some conceptual graph operations (e.g., join, match) (see Known Bugs and Restrictions)
• Ability to attach Wordnet glossary definitions or generic glossary entries to concepts and types
• Adjustable parameters for the matching scheme applied to joins and matching
• Custom colors for all graph objects, and the ability to set one’s own default color scheme.
• Ability to perform some concept acquisition via repertory grids
• Ability to export a repertory grid to Burmeister (CXT) format.
Features not currently supported
The following useful features are not currently supported; plans are to implement them in the future. Users are urged to note the list of limitations and bugs on page 40.
• Validation facilities (except for enforcing CG formation rules)
• Pasting (as in copy/paste) from other applications to CharGer windows.
• Ability for actors defined within CGs (actor plug-ins, written in Java, are supported).
• Type and relation hierarchies in CGIF format.
• CGIF import (under development)