Example-Based Retrieval of Alike Land-Cover Scenes From NLCD2006 Database

Query-by-image-content (QBIC) tools are in demand in geospatial community because they enable exploration and mining of the rapidly increasing database of remotely sensed images. Accompanying the growth of the imagery database is the increase in the number of image-derived products, such as high-resolution large-spatial-extent maps of land cover/land use (LCLU). QBIC-like tools for exploration and mining of such products would significantly enhance their value. In this letter, we present a method for retrieval of alike scenes from a category-valued geospatial database of which an LCLU map is a particular example. Alikeness between the two scenes is tantamount to similarity between their spatial patterns of class labels. Our method works on the principle of query by example, its input is a reference scene, and its output is a similarity map indicating a degree of alikeness between a location on the map and the reference. The two core components of the method are as follows: scene signature—an encapsulation of the scene pattern by means of probability distribution of class labels and the sizes of the patches that they form, and scene similarity–a mutual-information-based function that assigns a level of similarity between any two scenes based on their signatures. The method is described in detail and applied to the National Land Cover Dataset 2006. Two examples of queries on this data set are presented and discussed. The applicability of the method to other data sets is discussed.