Photogrammetric surveys are used to help identify the general topography of the area of investigation before one engages the field survey units. It is also used now to gather the latest ground information for the complication of GIS data. Photo mosaics produced help identify routes for new highways, transmission lines, gas pipelines etc. This method can ensure that the designed route will not pass over residential areas, sites of sensitive nature such as cemeteries, schools and historical sites. Photogrammetry will only be cost effective if the area of coverage is very large.