World Anchors
Most coordinate systems are absolute in nature. This means that 1 meter is always 1 meter. If you plot a point at 0.2 inches by 1.7 inches on a graph, you know the distance will be 1.5 inches. As previously explained, there are a lot of benefits of absolute measurement systems. However, without a way to measure in absolutes on a large scale and convert that to a mobile digital system, Microsoft had to find a different solution.
Some systems are relative, which means that they plot positions in relationship to other objects in the system; this type of system works better on a larger scale.
World Anchors or spatial anchors use a coordinate system that is primarily relative. With the HoloLens, the sensor array is always working, though it can be less than accurate at times. Lighting, the color of your fixtures, and furniture affect the scanning process. Sometimes, things get moved around and changed, and this can factor into the process as well.
World Anchors use the mesh generated...