1. A method for providing a 3D-point cloud using a geodetic surveying instrument, the method comprising: scanning a surrounding with the geodetic surveying instrument according to a defined scanning region; generating a scanning point cloud corresponding to the scanning region with reference to a surveying coordinate system which is defined by the surveying instrument; generating a first image on a side of the surveying instrument covering a region at least basically corresponding to the scanning region, the first image representing a reference image a pose of which is known with reference to the surveying coordinate system due to the position and orientation of the surveying instrument for acquiring data the first image is based on; capturing a first series of at least two images with an image capturing unit, the images having respective poses and partly cover the scanning region and an imaging region; and applying a Structure-from-Motion-(SfM) or a SLAM-algorithm at least comprising: identifying a first set of image points based on the reference image and on the first series of at least two images, the image points representing a first set of reference points of a reference point field, wherein each point of the first set of reference points appears in the reference image and in at least one of the images of the first series of images and position information regarding the points of the first set of reference points is provided by the scanning point cloud, and determining the poses for the images of the first series of images with reference to the surveying coordinate system, using the first set of reference points and the position information, the poses representing respective positions and orientations of the image capturing unit relative to the surveying instrument at capturing the images of the first series of images.