Limited display area creates unique challenges for information presentation and user exploration of data on
mobile devices. Traditional scrolling, panning and zooming interfaces pose significant cognitive burdens on the
user to assimilate the new context after each interaction. To overcome these limitations, we examine the uses
of "focus + context" techniques, specifically for performing visual analytic tasks with geospatial data on mobile
devices. In particular, we adapted the translucency-based "focus + context" technique called "blending lens" to
mobile devices. The adaptation enhances the lens functionalities with dynamically changing features based on
users' navigation intentions, for mobile interaction. We extend the concept of "spatial context" of this method
to include relevant semantic content to aid spatial navigation and analytical tasks such as finding related data.
With these adaptations, the lens can be used to view spatially clustered results of a search query, related data
based on various proximity functions (such as distance, category and time) and other correlative information for
immediate in-field analysis, all without losing the current geospatial context.
Interactive visual presentation of information can help an analyst gain faster and better insight from data.
When combined with situational or context information, visualization on mobile devices is invaluable to in-field
responders and investigators. However, several challenges are posed by the form-factor of mobile devices in
developing such systems. In this paper, we classify these challenges into two broad categories - issues in general
mobile computing and issues specific to visual analysis on mobile devices. Using NetworkVis and Infostar as
example systems, we illustrate some of the techniques that we employed to overcome many of the identified
challenges. NetworkVis is an OpenVG-based real-time network monitoring and visualization system developed
for Windows Mobile devices. Infostar is a flash-based interactive, real-time visualization application intended to
provide attendees access to conference information. Linked time-synchronous visualization, stylus/button-based
interactivity, vector graphics, overview-context techniques, details-on-demand and statistical information display
are some of the highlights of these applications.