I want to generate a random coordinate that would display anywhere on the map.
I've seen these two posts: 

https://gis.stackexchange.com/questions/236321/generating-random-lat-long-coordinates

And using this post for the JavaScript code: https://stackoverflow.com/questions/69221354/how-to-generate-random-longitude-and-latitude

And came up with the following:

```
function generateRandomLonLat() {
  return [Math.floor(Math.random() * 360) - 180, Math.round(Math.acos(2 * Math.random() - 1) * 180 / Math.PI) - 90];
}
```

But it also generates non-valid coordinates that are outside of the map.

Why?