it has been done ages ago, is called the maidenhead locator system, it is better in many ways, for example you can choose the granularity of the grid providing

it has been done ages ago, is called the maidenhead locator system, it is better in many ways, for example you can choose the granularity of the grid providing some privacy: https://en.wikipedia.org/wiki/Maidenhead_Locator_System https://en.wikipedia.org/wiki/Maidenhead_Locator_System