/explore: Markers don't appear when zoomed out to world scale

[rsargent]

More precisely, if the width is more than 360 degrees of longitude?

https://environmentaldata.org/#time=1606562250.922,1607167050.922&cursor=1607167050.922&plotHeight=5.000&plotAreaHeight=20.000&showFilters=true&showSettings=true&showResults=true&center=41.617318807058865,-0.5188805651700168&zoom=1

doesn't show at 915 pixels wide:

but does show at 905 pixels wide:

[dognotdog]

@rsargent this is a difficult thing because of the way the Google Maps layer reports visible coordinates when zoomed out super far. /browse has a half-working impl to place a single set of markers, but I feel like that is not quite the right solution.

Ideally, we would draw markers on all visible earth copies, but that requires some careful plumbing work.

[rsargent]

A relatively easy solution we've used in the past is to draw on the copy of the earth that crosses horizontally the center of the window.

[dognotdog]

@rsargent which is what /browse attempts, but I've found that impl to be broken, unfortunately :(