Great question. Most countries have a mapping agency/authority (https://en.wikipedia.org/wiki/National_mapping_agency https://en.wikipedia.org/wiki/National_ma

Great question. Most countries have a mapping agency/authority (https://en.wikipedia.org/wiki/National_mapping_agency https://en.wikipedia.org/wiki/National_mapping_agency). I've always assumed that each country defines it's own spatial boundary defined by the relevant legal agreements that define a country. Third parties such as Google presumably use whatever each country provides and try to stay out of any disputes (http://qz.com/218675/here-are-the-32-countries-google-maps-wont-draw-borders-around/ http://qz.com/218675/here-are-the-32-countries-google-maps-w...). As far as updates, someone probably just has an annual calendar reminder to pull the latest shapefile for each territory or from a central authority (UN? National Geospatial Agency?)! The geographer in me is mildly amused at the thought of someone in Belgium making a pull request to The Netherlands related to updating a boundary. If you're interested in questions like this, I highly recommend the FOSS4G conferences (http://2017.foss4g.org/ http://2017.foss4g.org/). Many of the big names in GIS attend and can likely give an authoritative answer on questions such as this.