Convert topojson to geojson

What is the difference between .topojson and .geojson?

Description: 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.; A GeoJSON file is a format for encoding a variety of geographic data structures using JavaScript Object Notation (JSON). It is a widely used open standard format designed for representing simple geographical features, along with their non-spatial attributes. GeoJSON supports various geographical data types such as points, lines, polygons, and multi-part collections of these types. It is commonly used for storing and exchanging spatial data on the web, as well as within various Geographic Information Systems (GIS).