How to export specified areas like parks

Good evening.

I would like to export specific area/polygon data’s from osm. As an example I want all park areas from a city or country. At the end I need a text file / database with all coordinates of a park Polygons to check if my position is inside of it. So I don’t want only to display the osm map as a background. I want to know on which ground(park/house,etc) I’m staying.

I downloaded already a few file Formates, but mostly can’t open them in a text editor.

How I can get and extract this informations best from osm?

I guess this is what you are looking for - simple example: