What is TopoJSON data?

What is TopoJSON data?

A TopoJSON file format is a format that encodes topology. TopoJSON is an extension of geoJSON. This format contains both geospatial data (arcs) and attribute data. Each arc is defined only once, but can be referenced several times by different shapes, thus reducing redundancy and decreasing the file size.

How do you use TopoJSON?

To create your own TopoJSON file:

1. Download shapefiles, for example from the remarkable Natural Earth.
2. Install the ogr2ogr and topojson tools. For example: brew install gdal npm install -g topojson.
3. Convert your shapefile to GeoJSON.
4. Convert your GeoJSON file to TopoJSON.

How do I install TopoJSON?

4 Answers

1. run npm install -g topojson in your command prompt.
2. use the command prompt to cd to the geojson file.
3. run topojson -o myNewTopojsonFile.json myOldGeojsonFile.json.

How is a TopoJSON file different from a GeoJSON file?

Rather than representing geometries discretely, geometries in TopoJSON files are stitched together from shared line segments called arcs. TopoJSON eliminates redundancy, offering much more compact representations of geometry than with GeoJSON; typical TopoJSON files are 80% smaller than their GeoJSON equivalents.

Which is an example of an extension of GeoJSON?

For example, London (51.5074° North, 0.1278° West) is [-0.1278, 51.5074] TopoJSON is an extension of GeoJSON that encodes topology. Rather than representing geometries discretely, geometries in TopoJSON files are stitched together from shared line segments called arcs.

What kind of applications can TopoJSON be used for?

In addition, TopoJSON facilitates applications that use topology, such as topology-preserving shape simplification, automatic map coloring, and cartograms .

How does The GeoJSON dataformat reduce file size?

This extension of the, meanwhile standardised, GeoJSON dataformat encodes topology of a GeoJSON dataset and reduces file size up do 80% ( see authors description ). In order to use this dataformat, it can be usefull to understand the structure of a TopoJSON file.