This paper presents a case study of user-generated geographic information in a small neighbourhood in Mexico City. It deals with citizen empowerment and actions directed to improve their local surroundings. It is constructed in a bottom-up fashion: from the citizens towards the local authorities. The exercise is carried out using an online platform developed for this purpose. The tools, methodology and lessons learned so far are described. This is an ongoing project and preliminary results are discussed. The acquisition of enough citizen data helps citizens focus their efforts when negotiating with the authorities, in situations and locations that have been found to be problematic. A digital map constructed by the citizenry is a helpful tool to locate areas of opportunity that require attention. Additionally, it is an effective communication tool to convey messages to the authorities. The identification of these types of locations is helpful in gaining insights into what, from the citizens’ perspective, can cause significant discrepancies between what they observe and what is officially reported. The proposed platform incorporates a way to validate official data, a voting strategy to assess the credibility of citizen contributions, and crowdsourced information on parcel data.