Polygon GeoJSON feature
measure unit type either metric or imperial
Precision of area value
OptionalareaUnit: areaUnitTypeIf undefined, it will be treated as 'auto' conversion of area unit according the default conversion rules. If a specific unit is set, the value is converted to that unit. If a callback function is set, it will be used for custom conversion.
OptionalmeasureUnitSymbols: MeasureUnitSymbolTypeOptional parameter to provide custom unit symbols
The returning feature will contain area,unit properties.
Calculate area from polygon feature