In this paper, we introduce to the special domain of image annotation watermarking, based on embedding of hierarchical data related to objects into user-selected areas on an image. In comparison to earlier methods, the main goal of the work presented here is to provide a specific robustness, specifically against cropping, in a way that preserves hierarchical object relations even after retrieval from a partial image, which has been cut from the original (pure security aspects are of limited relevance for our application). We identify two initial categories for such relations, visual-functional and visual-spatial and suggest a novel coding scheme for the first of these. Our prototypical system consists of a new ontology-based interactive editor and a watermarking scheme, which is an extension of previously suggested block-based image watermarking towards the specific requirements for annotation watermarking. Our initial experiments of the new approach include evaluation of appropriate ...