This application is also available with Large map.
The OpenStreetMap map type has been added to the Google Maps map types. It has been embedded as a layer within the Google Map. This will in many parts of the world give you map tiles with more details than the default Google Maps tiles.
The feature 'polygon with hole' ('donut') is built-in. Choose Polygon draw mode and follow the instructions. All overlays have style options. There are some custom markers (icons) available for Marker and Direction.
For editing - if you have a kml file uploaded on a server, and you want to edit its coordinates,
you may use my edit tool Edit tool for Google maps polyline and polygon
You will need a PC or laptop with a large amount of computer memory if your kml file has 1000 coordinate pairs or more.
If a coastline is part of the shape you want to create, you may use templates and build on them
Build Google maps polylines and polygons from templates
Example of use of my app: Qlik page in Qlik Sense Enterprise Documents.