When designing a user interface it is important that the user gets a good mental model of how the system works so that the user can guess how to use it and not have to follow instructions or learn everything. To give the user a mental model it is common to use
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interface metaphors. One example of such metaphor is the desktop in computers. The desktop corresponds to the physical desk and you can use a trashcan, put documents on the desktop and have folders that you put documents in both in the physical world and in the virtual world. Since people know what can be done with these things in the real world, it is easy for the user to understand how the corresponding things should be used in the virtual world.
The suggestions from the brainstorming session and inspiration from other appli-cations was the starting point for designing conceptual models. The models were just very rough suggestion for how to interact with the application and five suggestions are described closer here.
6.2.1 The cube
The first suggestion was to make a virtual cube that could be turned by sweeps in different directions. In this way each side on the cube could have its own functions.
This idea was inspired by the touch flow interface in the HTC Touch. The difference would be that this version had six sides in comparison to the three sides in the touch flow. An early sketch how this could be visualised can be seen in figure 6.1. The positive sides with this are that a cube is something that exists in the real world and that you could change view without having a button that takes up space. The negative sides are that there can only exist six sides and the interface could never be expanded into more views.
6.2.2 The flip chart
The second suggestion was to make a virtual flip chart where you could change page by making an upward sweep in the right or left side of the screen. How this suggestion could be visualised is shown in figure 6.2. The inspiration was my own sketching block that I used to make small drawings and notes for different interface suggestions. The positive sides with this suggestion are that I think that everyone that will use the application have also used a flip chart and therefore understands how to interact and if someone wants to expand the interface with more pages in the future that is possible. The most negative thing about it is that you can only turn page in one direction, you will eventually come around and find the same view again, but it can take many sweeps depending on how many pages there are in the chart.
6.2.3 Buttons
The third suggestion was to make a traditional user interface that uses buttons to navigate between different views. A suggestion for how this could be visualised is shown in figure 6.3. The good thing with this approach is that everyone that has ever used a software interface will recognise how to navigate, but on the other hand it will not be a memorable user interface.
6.2.4 The tree
The fourth suggestion was inspired first by Apptoos logotype that consists of three parts and where each part in my eyes looks like a leaf and secondly by the fact that I wanted to make a dynamic interface suggestion. The interaction is essentially the same as the button alternative but with a different visualisation. The thought was to make the
6.2. Design of conceptual models 27
Figure 6.1: Example of visualisation of the cube concept.
buttons into leafs and make them grow dynamically depending on how often they were used in the interface. If one leaf was used all the time it would grow and the other would shrink. How this suggestion could be visualised is shown in figure 6.4. The positive thing about this suggestion was that it is very dynamic, more leaves could be added at any time and it would be different from the other interfaces existing in mobile applications today. The negative sides are probably the same things, it is hard for the user to learn the interface if it constantly changes and it is harder to make a mental model if it does not work like anything else the user already have used.
6.2.5 Drag and drop
The possibility to use drag and drop and my own mental model of how mashups works were the inspiration for the fifth suggestion. The suggestion is to have three tabs that can be dragged out and overlap each other. If the tab with the map and the tab with the IM overlap each other, the IM contacts is shown with a position on the map. How this could be visualised is shown in figure 6.5. The positive aspect of this suggestion is that it clearly shows what the idea of the application is, to combine IM with positioning.
Figure 6.2: Example of visualisation of the flip chart concept.
The negative is that it is hard to expand the application with further functionality.
6.2.6 Evaluation
Since the process could not go on with all the suggestions, a few persons were asked about which suggestions they would like to use in this kind of application. All persons thought that the cube and the flip chat would be unpractical to use and that the other three suggestions were better. The drag and drop suggestion, the tree suggestions and the buttons suggestion were the suggestions that continued in the design process.