map navigation
Widget gallery Zooming
Zoom button
Magnifying glass most common metaphor for zooming in on web maps.
Being among the first web mapping applications, the TIGER Map Service was able to put its stamp on interface design for online mapping services. Since widgets have to be easily recognisable, the magnifying glass is a good metaphor for zooming. It can be found in many programme interfaces, for example in graphic design software and GIS systems.
Clicking on the zoom button with the mouse pointer only once, the scale of the map is magnified by a constant zoom factor, and the map view remains centered on the current centre of the map. The zoom button typically comes in pairs: one for zooming in (plus sign) and one for zooming out (minus sign).
Confusingly, the magnifying glass can be used for both a zoom button and a zoom tool. Clicking on the zoom button, the action occurs instantly. On the other hand, when clicking on the zoom tool, the tool is only activated: i.e. the behaviour of the mouse pointer changes, but the map page does not change. Sometimes the mouse pointer changes to a magnifying glass. When users click anywhere on the map, the map view is magnified with a constant scale and the map view is centered on the point where the user clicked.
User-defined zoom factor for quick map navigation.
Users click on an icon of the outline of Britain to set the zoom factor mentioned below the icon and then click on the zoom button to skip consecutive levels of detail. Similar to the horizontal and vertical steps, this widget is an example of non-sequential zooming. Users quickly change the map scale of the same geographic area as the map centre stays in the centre of the view.
The three icons of the outline of Britain increase in size and give a visual cue. However, when users click on any of these icons, there is no feedback: users are not informed about the current zoom factor either before or after clicking an icon. The zoom factor only becomes obvious upon clicking the zoom buttons. The zoom buttons positioned side by side are for zooming in (plus sign) and for zooming out (minus sign). Clicking on the zoom button, the action occurs instantly according to the specified zoom factor.