Patent ID: 7555487

Claim:
A method for determining whether first and second data files match, the first and second data files each having a set of data points, wherein each data point is defined by an x,y coordinate and has a characteristic corresponding to the data resident at the data point, comprising: dividing the first data file that is stored on a data store into plural segments; selecting at least one data point in each of the plural segments based on a predefined characteristic of the data point; identifying the coordinates of the at least one selected data point in each segment; creating a first set of identifiers for the first data file wherein the first set of identifiers includes a respective identifier for each respective segment and that is at least partially determined from the x,y coordinate of at least one selected data point in its associated segment; associating a respective importance value with each respective segment, the importance value associated with at least one of the segments differing from the importance value associated with at least one other one of the segments; identifying a second data file; creating a second set of identifiers for the second data file, the second set of identifiers includes a respective second identifier corresponding to each respective identifier in the first set of identifiers by being at least partially determined from the x,y coordinates of a data point in the second data file that has a characteristic corresponding to the predefined characteristic; comparing at least one identifier in the first set of identifiers to the corresponding identifier in the second set of identifiers; and assessing whether at least a portion of the second data file matches at least a portion of the first data file, based at least partially on results of the comparing and the importance value associated with each segment for which said at least one identifier in the first set is created.