A tutorial with examples of various access and display types can be seen at crotwell.github.io/seisplotjs. Also see the wiki. Install with npm i --save seisplotjs.

As a condition of using these data, you must cite the use of this data set. Such a practice gives credit to data set producers and advances principles of transparency and reproducibility. Other ...

When you look online for GeoJSON of Japanese prefectures, most results are approximate. The best resource out there is probably this gist but the files are already split by prefectures. Source data is ...