Simple Python script to write a list of coordinates to a .geojson file

This has probably been done better elsewhere, but here's a really simple way to write a geojson file programmatically to display a set of coordinates, without having to bother learning the syntax of yet another python library. Geojson is a cool little format, open source and really easy.

Below, arrays x and y are decimal longitude and latitude respectively. The code would have to be modified to include a description for each coordinate, which could be included easily on line 15 if in the form of an iterable list.