Hey,
I created a similar thing: https://github.com/mojo2012/factorio-mojo-resource-processing
It works by using a shovel on the ground. It digs a water hole where there is land and vice versa.
Maybe you wanna join me by even further extend my mod? (eg digged holes are not automatically filled by water, but are just holes, only filled when adjacent to a water tile, ...)
