The rapid urbanization in most Low- and Middel-Income Countries (LMICs) combined with an insufficient supply of low-cost housing is leading to the growth of deprived urban areas (commonly known as slums or informal settlements). The UN is estimating that around 90% of the urban growth will happen in LMICs, mostly in deprived areas. The improvement of living and environmental conditions in these areas are on the global development agendas (e.g., SDGs, NUA). However, there are commonly insufficient data to guide policies and local actions that would be required understanding specific local conditions and needs. The presentation shows examples of ongoing efforts to build open data on living and environmental conditions, combining Earth Observation and Geospatial data with local knowledge. The projects focus on the development of data ecosystems with local stakeholders. For example, within IDeAMapSudan, a Geonode was developed to share data with an between local stakeholders. Furthermore, within the recently launched 2nd phase of IDEAMAPS, a data ecosystem will be co-designed that supports the integration and exchange of data between local community groups, governments, and academia.