Abstract: With the purpose of discovering the geographical topics from GPS-associated images,a novel geographical topic model,which is called Author-related Geographical Topic Model(AGTM),is proposed and implemented.AGTM increases the accuracy of geographical topic by introducing author information and their relationships into the traditional modeling process.It assumes that if two authors are friends their documents will have a greater probability of being clustered into the same topic.Under this assumption,AGTM divided authors into several social groups,while social groups are assigned to certain geographic regions under some probability distributions.Experiments performed on a dataset of Flickr images with GPS coordinates and other attributes indicate that our approach achieves a better accuracy and interpretability for modeling geographical topic.