Convert gpx to topojson

What is the difference between .gpx and .topojson?

Description: A GPX file is a GPS data file saved in the GPS Exchange format, which is an open standard that can be freely used by GPS programs. It contains longitude and latitude location data that may include waypoints, routes, and tracks. GPX files are saved in XML format, which allows GPS data to be more easily imported and read by multiple programs and web services.; TopoJSON is a file format for encoding geographic data structures, based on the GeoJSON format. It encodes geometries more efficiently and supports topology, which enables more accurate representations of geographic objects. TopoJSON eliminates redundancy and simplifies data, making it smaller and easier to work with.