Systematic conservation planning and spatial conservation prioritization are closely related fields of conservation science. They are concerned with the spatial allocation of conservation resources into actions such as expansion of reserve networks and allocation of habitat restoration, management or maintenance. Decision analytic techniques including optimization are heavily used, with the implication that sufficient data must be available to allow analyses that have relevance for on-the-ground planning. Most commonly, analyses are based on data about species distributions, costs and threats. However, in many parts of the world, including much of the tropics, comprehensive data about species distributions is not available. Are there feasible and robust methods for the allocation of conservation action when data is limited and species-based systematic conservation planning is not feasible? In this work I discuss spatial conservation prioritization and its application when data is limited -making a contrast to the case where ideal data is available.