1. A system, comprising: a computer comprising a memory, the memory storing instructions for maintaining (a) a first data object for storing a first set of feature data in a first format, the feature data including a plurality of features and the first format including human-readable data, and (b) a second data object for storing a first set of image data in a second format, the second format including computer-readable and not human-readable data, wherein, for each feature in the feature data, the feature data includes an identification of at least one point where the feature is to be overlaid on the image data, said instructions further including instructions to: include, in a graphical user interface, a display based on at least some of the first set of feature data overlaid on at least some of the first set of image data according at least in part to the identification of the at least one point where each feature is to be overlaid on the image data; send at least one query; receive, in response to the at least one query, a second set of data that includes one and only one of (a) a second set of feature data in the first format and not image data in the second format or (b) a second set of image data in the second format and not feature data in the first format, whereby the second set of data includes data for replacing one and only one of (a) at least a portion of the first set of feature data and not any of the first set of image data or (b) at least a portion of the first set of image data and not any of the first set of feature data; and modify the display based on at least some of the second set of data without modifying any portion of the display based on data not replaced in the second set of data.