Barcodes (also called barcode symbologies) are visual representations of data encoded in a machine-readable format that is recognized by the International Organization for Standards (ISO) and GS1. Barcode symbologies — generally speaking — come in two forms: 1D (one-dimensional) and 2D (two-dimensional). 1D barcodes were the first type of barcode to be standardized and consist of white and black spaces of varying widths that depend on the specific symbology standards. 2D barcodes were later introduced as a solution that could store a considerably larger amount of data than one-dimensional barcodes. Two-dimensional symbologies are typically more complex, often incorporating complex geometric patterns that consist of dots, rectangles, hexagons, et al. Like 1D barcodes, the patterns in 2D barcodes depend on the specific symbology's standards. Both 1D and 2D barcodes come in a number of various symbologies, each suited to fit a specific need.

1D Barcodes2D Barcodes
Represented by black and white "bars"Represented by geometric patterns
Capacity of approximately 25 charactersCapacity upwards of 2000 characters
Requires less expensive hardwareRequired more expensive hardware to read 
Limited tolerance to errors and damageResistant to errors and damage 
Stores data horizontally Stores data horizontally and vertically in matrixes
Ideal for simple data, such as alphanumeric and some control charactersIdeal for a wide variety of data, including URLs and URIs