Informal settlements pose a major challenge for managers and planners of developing world cities. Failure to inter- vene in a manner that improves residents' quality of life may lead to social and political unrest. Due to continually changing internal social and political environments in these settlements and to frequent changes in the arrangements of shacks, spatial and social data need to be collected more frequently than for conventional development tasks. What are needed are simple, low-cost techniques that preferably involve community members in collecting the data. Palmtop computers, group workshops, and voice recordings incorporated into digital records, digital still and video imagery, and semi-automated feature extraction techniques are methods that have been developed and tested in a number of settlements in Cape Town, South Africa, along with one in Dar-es-Salaam, Tanzania, and that can be used to address these needs.