This Minor Field study was carried out during May and June 1999 in Metro Manila, the Philippines. The purpose of the study was to investigate the following: · Evaluate if SPOT images combined with existing maps can be a relevant source of information in search of vacant lots in highly urbanized areas. · Try to identify land suitable for socialized housing by recording information about vacant lots in a Geographic Information System (GIS). · A price and accuracy comparison between high-resolution satellite images and aerial photographs. Today there is no current operational system for keeping records of vacant land, which makes systematic field inventories the most common way of updating land use maps and identifying vacant lots. Systematic field inventories are extremely time consuming and also physically tiresome in the warm and humid climate in Metro Manila. If SPOT images could assist in pointing out vacant lots with sufficient accuracy, this would be of great help when sites suitable for socialized housing shall be identified. A land inventory in San Juan, Metro Manila was conducted to determine the impact of SPOT images as a relevant source of information, in search of vacant lots. It turned out that the most crucial assumption, which the approach was based on, was wrong. This assumption stated that highly urbanized areas have little or no vegetation and therefore it is most likely that vegetation that can be found in such areas, will be found in vacant lots. The problem was, that there was too much vegetation growing in other places than in vacant lots. To compensate for this an attempt to find a vacant lot's unique spectral characteristics was made...