Example ballpark polygon

ballparks-poly.geojson

{
"type": "FeatureCollection",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
"features": [
{ "type": "Feature", "properties": { }, "geometry": { "type": "Polygon", "coordinates": [ [ [ -122.390210448844414, 37.77736347432851 ], [ -122.390353922651201, 37.777442591458744 ], [ -122.390250488046306, 37.777561266995335 ], [ -122.390557455260819, 37.777727412426508 ], [ -122.390784344071534, 37.777513796803554 ], [ -122.391171389689845, 37.777827626950476 ], [ -122.390994549881469, 37.778025418375421 ], [ -122.391024579282899, 37.778046516096182 ], [ -122.390847739474552, 37.778228483687805 ], [ -122.390817710073122, 37.778278590627139 ], [ -122.390824383273454, 37.778315511508062 ], [ -122.390967857080199, 37.778405176427846 ], [ -122.389312903402001, 37.779713217008926 ], [ -122.389269527599964, 37.779684208295393 ], [ -122.389209468797119, 37.779734314247982 ], [ -122.387808096730879, 37.778605603502307 ], [ -122.387831452931977, 37.778560771177567 ], [ -122.387861482333392, 37.778518576023565 ], [ -122.387894848334966, 37.778486929642256 ], [ -122.387951570537652, 37.778455283247411 ], [ -122.388004956140165, 37.778439460045838 ], [ -122.38795824373797, 37.778188925529548 ], [ -122.389850096027402, 37.777461052110276 ], [ -122.389886798629135, 37.777487424461626 ], [ -122.389886798629135, 37.777487424461626 ], [ -122.390210448844414, 37.77736347432851 ] ] ] } }
]
}