A global 3D map works with data from various sources: DEMs, orthomosaics, vectors or even 3D city models. The data is acquired by diverse sensors and processing techniques and varies vastly in resolution and geospatial coverage. Need for partial updates may arise as more recent or higher resolution data becomes available. Integrating all this data into a single, meaningful cartographic or VR product gives rise to the data fusion problem on an ever growing scale. VTS geospatial software stack provides a simple yet powerful way to tackle common 3D data fusion scenarios. In this talk, we will provide a hands-on demonstration.