Creating new layers

Revision as of 15:37, 25 June 2008

Topic map standard defines a merge operation between identical topics. Merge operation is extremely powerful as it allows incremental knowledge building. Knowledge packets addressing same topics superposition. The only problem with merge rules is that the source of topic is lost. You can't recognize which source assigned which topic element. Backtracking the merge is essential because original topics may contain errors. Backtracking also ensures trust between knowledge sources and aggregators. One backtracking method is to allow the aggregator to cancel and redo the merge easily.

Wandora supports layered topic maps. Layered topic map contains one or more topic maps stacked into an ordered array. Wandora user can add and delete topic maps in the layer stack. User can also make topic map layer invisible and lock layers.

The concept of layers and layer stack in Wandora is similar to the layer concept of many graphic creation and manipulation applications such as Adobe's PhotoShop where single image may contain multiple layers and graphics designer manipulates one layer at time. Layer implementation in graphic application ables the designer to isolate finished image parts from unfinished and enables rapid versioning. This is the motivation behind Wandora's layer implementation also. To make designer's life easier.

Wandora's layer stack locates in bottom left corner of Wandora window. When you start Wandora, application reads topic map from conf/wandora.xtm and creates the layer Base for it.

To create another layer you can

• Drag and drop XTM, LTM or RDF(S) file to the layer stack. Wandora imports the file and creates a new memory layer for the imported file.
• Select Layers > New layer or press ALT+N. This opens layer creating window used to define layer type and properties. Current version of Wandora supports memory, database and remote layers.

Creating Memory Layer

Configuring new memory layer is very easy. Just enter layer's name and choose to import XTM topic map file to created layer, or not. Below is an example of memory layer configuration panel.

You can also select to import Wandora's mini ontology conf/wandora_mini.xtm to the created layer. This mini map contains a set of Wandora's fundamental topics and associations. After layer creation you should see new layer at the left bottom of application window.

Letter M marks for a memory topic map layer. Letter D marks for a database topic map layer.