2D Barcode - What is the difference between linear and 2D barcodes?

Linear barcodes and 2D barcodes differ in their data storage capacities and physical appearances. Linear barcodes, containing only vertical lines, store data in the horizontal direction. On the other hand, 2D barcodes, with their checkerboard-like pattern of small elements, store data in both horizontal and vertical directions. Beyond their visual differences, there are also important technical distinctions between the two.