Which type of charts are scanned copies of paper charts?

Raster charts, also known as Raster Navigational Charts (RNC), are indeed scanned copies of traditional paper charts. These charts represent a digital format of nautical charts, where the paper chart is scanned and converted into a raster image. This means that they retain the exact appearance of the original paper charts, including details such as colors, symbols, and text.

The key aspect of raster charts is that they are essentially pixel-based images and do not include vector data, which can be manipulated as mathematical points and shapes in vector charts. Therefore, when using raster charts, users cannot zoom in indefinitely without losing clarity due to pixelation, unlike vector charts that allow for scalable images. As a result, raster charts are utilized primarily for navigation and reference purposes, offering a direct representation of what mariners would see on paper charts but in a digital format.