53% 
conducted jointly by the Instituto Geografico "Agustin Codazzi" (IGAC) of 
Colombia and the National Research Council of Canada (NRCC). It is 
financially supported by the Colombian and Canadian Governments. About two 
thirds of the project budget is supplied by the Colombian National Department 
of Planning and the Colombian Ministry of Finance and Public Credit and one 
third by the Canadian International Development Agency. 
The pilot study is carried out for a 2000 km? test area containing 
approximately 20 000 parcels, with topographical features, land-use patterns, 
and soil types which are representative for the agricultural areas of 
Colombia. The area also includes typical built-up areas such as villages and 
towns of various sizes. The general objective of the project is the 
establishment of a prototype cadastral land information system based on the 
implementation of modern concepts, methods and technology, which will allow 
for testing and analysis of procedures for acquisition, processing and 
exploitation of information (Jaksic, 1981). 
The project consists of two different phases. The first one was completed 
during the summer of 1983 and consisted, among others, of the installation of 
hardware, selection of the test area, aerial photography, aerial 
triangulation, and development of prototype software for data collection and 
information management. 
The second phase, which is presently in progress, is concerned with the 
overall analysis of the system, introduction of possible refinements and 
corrections of software, and definition of detailed specifications for 
country-wide implementation of a cadastral land information system. 
SYSTEM COMPONENTS 
The Colombian land information data base is organized as a geocoded system, 
containing cadastral geometrical information on properties, soil types and 
land use patterns as well as cadastral attribute data such as name and address 
of a parcel, its owner, its cadastral value, dates of changes in ownership, 
types of buildings, etc. The digital information is used to define the parcel 
boundaries in the data base, to calculate areas, elevations, and slopes and to 
produce cadastral base maps and graphical records for individual parcels. The 
digital and attribute information are stored in different files and the 
cadastral parcel identification number is used as a key to retrieve the two 
types of information for a particular parcel (Jaksic and van Wijk, 1983). 
The photogrammetric system components, installed at IGAC during the first 
phase of the project, will allow for the evaluation of various photogrammetric 
.on-line techniques. The data acquisition for the rural areas is based on the 
stereo-orthophoto technique which offers simple instrumentation for digitizing 
planimetric and elevation data. In the field interpretation stereo- 
orthophotos offer the advantage over regular aerial photos that they represent 
the terrain in orthogonal projection. The orthophoto scale is uniform and 
straight boundary lines appear therefore straight in the orthophoto image. 
This allows for the use of simple tape measurements to define in the 
orthophoto those boundary points which cannot be readily interpreted. The use 
of stereo-orthophotos, offers the possibility to observe a true three- 
dimensional terrain model by using a simple field stereoscope. The field 
interpretation data, such as parcel boundaries, cadastral reference numbers, 
and land use patterns are marked on orthophoto mosaics, arranged according to 
the cadastral map sheet system. After completion of the field identification 
these mosaics offer a preliminary, up-to-date, graphical cadastral record, 
even before the digitizing of the information is initiated.