What is the difference between a 1D barcode and a 2D barcode?

A 1D barcode only encodes data along the width of the barcode, while 2D barcodes encode data along both the width and height. 2D barcodes are therefore much denser than 1D barcodes and encode much more data in the same space. 2D barcodes are also much better at detecting and correcting errors in damaged barcodes.