I learn the most about UI design and functionality from simply watching people use my applications. One thing I’ve noticed lately, while watching people use the zoom controls on the World Freedom Atlas, is that the online maps style of pre-set zoom levels has been internalized by many users. They are not used to a continuous zoom control that allows them to precisely determine the map scale.
What does this mean for cartographers, or for UI design for internet maps? It means that users will likely click our zoom controls, and anticipate a tween into a new zoom level. When I designed the zoom controls for the WFA, I anticipated that users would click-and-hold the zoom controls to smoothly zoom to the desired level. People who expect the fixed zooming, then, end up repeatedly clicking my plus and minus buttons, leading to inefficiency and increased mouse mileage.
So how to take advantage of the flexibility of continuous zooming, while also accomodating these online maps users? Simply provide a nice fixed-style zoom if the user clicks the zoom control, while maintaining the smooth continuous zoom for those who know to hold down the buttons.
