In the early days of Wi-Fi, site surveys were fairly basic and involved running around with a laptop looking at simple signal levels. The next step was mapped-based tools that provided a good visual of Wi-Fi coverage, but still involved carrying a bulky laptop around.
Today, we have map-based Wi-Fi surveying mobile apps you can run on your Android-powered smartphone or tablets. These allow you to create heat maps of Wi-Fi coverage using a small and lightweight device. And for those vendors that offer a laptop-based surveying product, the data can be exported there for further analysis.