draw around buildings from uk aerial imagery

Hello, I am in need of a freelancer who is able to draw around 20,000 buildings from UK aerial imagery for an upcoming project. The purpose of these drawings is for flood modelling, and should include roof shapes with highly detailed accuracy. Experience with mapping and aerial imagery is necessary to accomplish this task. Please include previous work examples or portfolios in your submission so I can get an accurate gauge of your ability to finish this work. Thanks for your time!