This Master Thesis revolves around the theme: ``Augmenting the city'' and focus on digitally presenting context. The Thesis primarily consists of two papers, the first paper is mainly technical and the second paper takes origin in the experience gained from the first paper and introduces the concept Digital Urban Ambience.

In the first paper we report on how emerging technology in Smartphones can be used to present photos in context, inspired by the spatial information they hold. An application running on an Android Smartphone was created. The application was called PhotoWorld and uses 3D accelerated graphics to explore the possibilities of presenting photos related to the surroundings. A user study was conducted, which were followed by a Grounded Analysis to investigate and concretize any themes or concerns. Our findings show that a presentation of temporal data in context can add a lot to the user experience, but that spatial information can be ambiguous and not necessarily easily understandable. We identified several presentational and conceptional problems. This increased user satisfaction mixed with the identified problems propose interesting challenges for presenting photos in context.

In the second paper we present the term Digital Urban Ambience, directed at context-aware mobile systems in an urban environment, facilitating a user-driven context creation by digitally presenting context rather than trying to adapt to it. An application, called AalborgLive, based on Digital Urban Ambience is implemented and a field evaluation with 58 participants is conducted. We find that AalborgLive is used in a quite spontaneous pattern, which makes for a fast ``finger on the pulse'' of the surrounding environment, and that interactive dynamic content plays an important role in the user experience. Finally we discuss our experiences with Digital Urban Ambience.

The main contribution of this Thesis is the Digital Urban Ambience concept that can be used to present context by Augmenting the City with digital context creation. An approach to Augmenting the City that in our evaluation received good feedback and puts more attention on the idea of presenting the context, instead of adapting to it. We find that an understanding of the urban environment as an ever-changing entity is important when using the concept of Digital Urban Ambience, as live data and having interactive means of tuning into the ever-changing content, lays the foundation for a good user experience.