Build a roofing measuring system

The project is as follows: This is a website, which the user must log into to use. The user types in their address, and then can see a sky-view of their house/building. Once they are happy with the selection they see, a screenshot is taken of that map at a fixed height. This will ensure the measurement ratio remains constant. The user will then be able to use a line tool in order to measure the sides of the house, as well as trims, eaves, etc. Since the height is constant, the length of the roof should always be measured with the same scale. The sides should be able to be linked together to make squares for each section of the roof. Kind of like a pen tool in Photoshop. The user should be able to start with another panel's side too, if two parts of the roof share the same edge. The sides of the roof is the ONLY thing which actually needs to be measured by the system. Everything else can be measured based of the numbers gained from the line measurements, constants, and inputs from the user. For instance, the waste factor will be input by the user. After all this is confirmed by the user, a pdf document will be generated based on the information, and will be downloadable by the user. If the user has done this process before, the user should have then option of picking one of the previous houses they've measured to view the stats, or measure a new one. The code must also be clean, and editable, as we will be editing the website ourselves in the future. PLEASE READ THE ATTACHED DOCUMENTS FOR MORE INFORMATION ON THE PROJECT. Eastern Time Zones or anything closer preferred for time coordination purposes.