Line-of-sight (LOS) probability is an integral part of radio channel models for cellular network design and evaluation. The probability along with the pathloss models in LOS and non-LOS scenarios gives us an estimate of the cellular coverage. In this letter, we present a novel method to evaluate the LOS probability by using point cloud data obtained with laser scanning. The LOS probability is derived for two new scenarios, an urban open square and a shopping mall, along with an office environment, and a generic exponential LOS probability model, which shows excellent performance in the tested environments is proposed. Also the frequency dependency of LOS probability is investigated.