1.1. Portrayal of Geographic Information

Introduction

The lesson Techniques for LBS Cartography described various constraints that a mobile device has in comparison to more conventional technologies, such as a desktop computer. Amongst these restrictions were:

• Small display screens with low resolution
• Low bandwidth and intermittent network coverage
• Limited memory and computational power

In addition to theses physical limitations, Lesson Designing maps for LBS described more human factors that must also be considered. These included, that mobile device usage is:

• Based on short and frequent interaction sessions
• Related to specific activities which are tied to different types of services
• Related to context (e.g. location, time, etc.)

In those lessons such factors were dealt with from a relatively conventional cartographic perspective, in terms of how map content can be compiled to make it relevant, how interaction with maps can be enabled, how the design and styling of maps can be best performed to cope with constraints, and how different techniques for map provision can be used to optimise the usage of the available resources.

In this lesson we will consider such factors again, however, now we will take the perspective of developing the functionality of the map interface in ways that enchance the visualisation of information by fundementally changing how the information is portrayed. This is done to cope with three different types of restriction:

• Physical constraints - limitations imposed by the device and network infrastructure
• Human factors - limitations on map reading caused by the nature of mobile use
• Graphical constraints - restrictions from the graphical styling used to depict information