Human geospatial activities often involves the use of geographic information in mobile environment where the context of technology use is dynamic, complex, and unstable, creating unique challenges in designing effective mobile mapping applications. Enhancing the context awareness of the computing device can improve the usability of mobile map applications, but the potentially large number of contexts (physical context, computing context, human factors, and time) are not easily managed without a workable organizing structure. This paper proposes an activity-oriented context model that establish late (run-time) binding of contexts to the ongoning avtivity according to how they contribute to the success of the activity. Using this context model, adaptation of mobile map display to the changes of other contexts is based on the knowledge of ongoing task (within an activity) rather anticipated tasks. We discuss advantages of such an approach over traditional template-based model of context models in mobile computing applications.