VUE supports the merging of a set of maps into a single map and offers two modes for visualizing nodes and links that are shared across maps: weight or vote. Weight mode color codes the nodes based on frequency of occurrence. The vote mode enables users to set a threshold to show nodes and links that meet a specific requirement (e.g., nodes and links that are in at least 35% of the maps). Using an ontology is not required to use the merge maps tools, as the merging is currently based on node and link labels. VUE will allow maps to be merged on unique IDs or a combination of a node’s metadata.
A unique id, as the name suggests, uniquely defines a node. Typically, the label of a node serves as its unique id. VUE has built-in support to allow some other property, such as a metadata element or a combination of metadata elements of a node to be a unique id. This is helpful when a map contains two nodes with the same label (i.e. Washington); one of the nodes referring to a city and the other to a person. In such cases users will define a metadata element that will clarify the node.