Improvements in computer processing power and broadband technology have led to the development of interactive systems for navigating imagery, such as geographic imagery. Some interactive map navigation systems provide a user interface with navigation controls for navigating cities, neighborhoods, and other terrain in two or three dimensions. The navigation controls enable users to tilt, pan, rotate, zoom, and activate terrain and buildings for different perspectives at an area of interest. Exemplary map imaging systems include the Google Earth and Google Maps systems by Google Inc.
The imagery used by these interactive systems can be derived by rending geometric objects and texture objects to generate a two-dimensional or three-dimensional graphical representation of an area of interest. The geometric objects can define three-dimensional surfaces of objects and terrain depicted in the imagery. The texture objects can be mapped to the three-dimensional surfaces to add detail, surface texture, color and other features to the depicted objects and terrain.
Interactive systems for displaying imagery, such as geographic imagery, often render geometric and texture objects with low level of detail (“LOD”) (e.g. low resolution) at camera views far from an area of interest to improve performance. As the user zooms in closer to the area of interest, geometric and texture objects with higher LOD (e.g. higher resolution) are rendered to depict objects in greater detail. Switching between two levels of detail can cause a distracting pop if the levels of detail are sufficiently different and/or the transition happens too close to the camera view. The pop can be a visual anomaly which disrupts the user's sense of immersion in the imagery. Moreover, if the geometric data and the texture data are fetched from a server over a network, the latency between the request for higher resolution objects and the receipt of the data by the client can be long. In this case, a user can zoom in past the natural resolution of a rendered scene, resulting in a blurry image. When the higher resolution imagery finally arrives from the server and is rendered, the higher resolution imagery will “pop” into view because its resolution is markedly different from the imagery in the previously displayed blurry image.