programming language for building a geographic information system?

I want to build a GIS application (web or desktop) and I don't know where to start. The user in my case can upload an image, and then draw basing on that image all points, lines and polylines (depends on his needs) .. I will need to store all informations to calculate distance and superficie .. Please share with me tolls and language that can help me developing this app ? and it is better to make a Web-app or a desktop app