ol.source.Vector sources use a function of this type to load
features.
This function takes an ol.Extent representing the area to be loaded,
a {number} representing the resolution (map units per pixel) and an
ol.proj.Projection for the projection as arguments. this within
the function is bound to the ol.source.Vector it's called from.
The function is responsible for loading the features and adding them to the
source.
ol.source.Vector sources use a function of this type to load features.
This function takes an ol.Extent representing the area to be loaded, a
{number}representing the resolution (map units per pixel) and an ol.proj.Projection for the projection as arguments.thiswithin the function is bound to the ol.source.Vector it's called from.The function is responsible for loading the features and adding them to the source.