DGN files are drawings created by and supported by CAD applications such as MicroStation and Intergraph Interactive Graphics Design System. It is used for creating and saving designs for construction projects such as highways, bridges, and buildings. The format is similar to Autodesk’s DWG file format and is considered its competitor.
SVG files are Scalable Vector Graphics Files that use XML based text format for describing the appearance of image. The word Scalable refers to the fact that the SVG can be scaled to different sizes without losing any quality. Text based description of such files make them independent of resolution. It is one of the mostly used format for building website and print graphics in order to achieve scalability.
You can also convert DGN into many other file formats. Please see the complete list below.