Provide some content on Working With Geographical Data

Read me first: [refer to this issue](https://github.com/VCityTeam/VCity/issues/260)

Elaborate on the content of [the WorkingWithGeographicalData.md file](https://github.com/VCityTeam/UD-SV/blob/master/ImplementationKnowHow/WorkingWithGeographicalData.md).