1. A method for extracting feature data from very high resolution (VHR) remotely-sensed multispectral Earth imagery, comprising: storing VHR remotely-sensed multispectral Earth image data in a file system; providing a plurality of feature extraction modules, wherein each respective feature extraction module is operable to analyze the image data to generate feature data regarding the image data; accessing the VHR remotely-sensed multispectral Earth image data in the file system with one or more of the plurality of feature extraction modules, wherein the one or more feature extraction modules each access the file system using a common interface format; executing the one or more feature extraction modules to generate feature data corresponding to the VHR remotely-sensed multispectral Earth image data; and receiving the feature data at the file system from the one or more feature extraction modules, wherein the feature data is received from each of the one or more feature extraction modules using the common interface format; wherein at least one of the feature extraction modules comprises a clustering histogram feature extraction module for extraction of feature based on clustered and classified spetra values, and wherein the clustering histogram feature extraction module is operative to generate feature data by: assigning each pixel of an image into one of a plurality of predefined classes; identifying kernel surrounding each pixel containing a plurality of other pixels from the image, wherein each of the plurality of other pixels have been assigned into one of the plurality of predefined classes; building a histogram for each pixel based on the number of other pixels in each of the plurality of predefined classes relative to the pixel for which the histogram is built.