A Venetian canal, know to Venetians as a rio, is a remnant of an ancient natural waterway. The canals today resemble their original appearance but have transformed slightly due to human intervention. A canal can be classified as an inner canal or and outer canal. An inner canal separates two islands in the historic center of Venice, while an outer canal runs along the exterior of Islands in the lagoon. A canal may vary in size, shape, and number of intersections however its anatomy is typically consistent, as explained below. Every canal is broken up into Canal Segments by intersections. For research and organizational purposes Canal Segments are given sub names originated from the canal name.