Thanks to remote and face-to-face evaluations, and also thanks to discussions, which arose with export blind users, it was possible to better understand how blind people can make a mental image of a diagram. In particular some relevant considerations can be remarked:
- as for simple diagrams without a great amount of written information and without many connections, blind persons prefer tactile representations. Actually simple tactile diagrams can be perceived by touch quickly and different parts (two nodes, two connections, a node and a connection, etc.) can be understood synchronously, likewise sighted persons can do by observing a diagram by sight;
- as for complex diagrams (i.e. those diagrams that contain many captions and a great deal of connections and nodes) tactile representations aren't enough, therefore Braille and audio interaction is preferred.
Audio and Braille exploration can't enable a blind to understand synchronously the diagram, but there are techniques to achieve synchronous exploration, namely the overall glance. These techniques were better understood during the project and they can be divided in two groups:
- direct access to known or unknown parts of diagram (i.e. search node, select node from a list, etc.). The sighted exploration allows to directly finding a piece of information in a diagram. These techniques allow achieving the same purpose.
- aggregation of nodes. The exploration by aggregating groups of nodes is a way to simplify a diagram so that the parts and their relations can be easily understood.