In my former life in US-GEO (MapPoint, Streets & Trips, 1997 or 1998) at Microsoft, one of the tools I worked on normalized data sets from disparate vendors. One of the largest jobs we had was figuring out mappings from the "north" of one vendor and the "north" of another, as the vendors for high-quality data sets varied from locale to locale.
Frequently, you would need to rotate and transform the data to get it close enough that the geometry could be snapped together. This usually required some manual intervention; nothing like the human eye for detecting an array of streets suddenly had a 1 degree kink where it crossed some stitching line.
Our licensing for the data sets was very strict, and deformed the products in interesting ways, as you might imagine.
My fondest memory of working with that group was inserting POIs - we all got a POI, provided it wasn't obscene or something. I named a feature close to where I grew up; sadly, the POIs were culled every edition.
Frequently, you would need to rotate and transform the data to get it close enough that the geometry could be snapped together. This usually required some manual intervention; nothing like the human eye for detecting an array of streets suddenly had a 1 degree kink where it crossed some stitching line.
Our licensing for the data sets was very strict, and deformed the products in interesting ways, as you might imagine.
My fondest memory of working with that group was inserting POIs - we all got a POI, provided it wasn't obscene or something. I named a feature close to where I grew up; sadly, the POIs were culled every edition.