I am creating a graph neural network model for predicting the flow of water on a terrain. To train the model, I am passing a Digital Elevation Model file as input and extracting a rectangle out of entire file for training it. Based on the area extracted, I am generating momentum and velocity of water in X and Y directions depending on the physical features. After training, while checking the visualization, I am observing that the arrows representing the flows are being concatenated at the bottom of the output.