AbstractThe paper deals with a study commissioned by the Ordnance Survey. The nature of development aid is discussed, and the methodology of the study is described. This involved examining a sample of recent development aid projects in order to identify the inputs to each project from surveying, mapping, land tenure and remote sensing. The principal results of the study include the recognition of indirect and direct inputs to actual development projects; modest data on their costs and the benefits which have accrued; an approach to establishing the significance of the inputs; and guidelines on inputs for overseas governments and development agencies.