Abstract: A method for encoding 2D numerical data comprises determining encoding parameters for a received set of 2D numerical data and generating a set of encoded data from the set of 2D numerical data according to the encoding parameters. The encoding parameters indicate a transitional relationship among a plurality of consecutive data points and a unitization interval for sampling the first set of 2D numerical data. When generating the set of encoded data, the encoding method sets a starting point, samples the set of 2D numerical data according to the unitization interval, and determines a string as a value of each data point of the set of the encoded data. The string indicates a position of a present encoded data point in the set of the encoded data, the transitional relationship, and a difference of magnitude between a present encoded data point and an immediately preceding one.