REPORT TO THE XII INTERNATIONAL PHOTOGRAPHIC 
SURVEYING CONGRESS (OTTAWA, 1972) 
1. General remarks 
Photogrammetry in Spain since 1968, the date of the last International Congress in Lausanne, has been on 
the rise insofar as improvement of methods, growth of available equipment, and development and implementation 
of new techniques are concerned. 
The chief cause of this sustained growth is the revitalization of the domestic economy under a succession of 
development plans providing for numerous projects in public works, highway and road building, construction 
of dams and irrigation systems, etc., along with the surveys required for statistical purposes and location of natural 
resources. The result has thus been a constant demand for cartography of all scales. 
Within the general background of growth, the following are some of the more important trends that have 
been observed in the course of this period: 
— Adoption of photogrammetry by numerous new government agencies and private concerns. 
— Increase in the number of photogrammetric instruments. 
— Predominance of aerial triangulation methods for obtaining control points for small and medium scales. 
— Increase in the production of large-scale (1:500 and 1:1,000) and small-scale (1:25,000 and 1:50,000) 
maps. 
— Application of orthophotoprojection techniques. 
— Research in the development of digital models and in the automatic processing thereof. 
— Exceptional increase in training, and use of, photographic interpretation. 
2. Aerial photography 
During the period 1968-1972, the production of aerial photographs has continued to grow, not only of photo- 
graphs for plottin purposes, but also of ones for interpretative use, the latter being the field where growth has 
perhaps been sharpest. More and more flights are being made for purposes which can be characterized as fun- 
damentally qualitative. 
In the field of sensitive emulsions, use of the panchromatic varieties continues to be predominant, although 
infrared types in black and white are now in quite widespread use. Furthermore, color and false-color flights 
have been conducted for purposes of interpreting plant diseases and plagues. 
Photographic flights are conducted by a government agency, the Photographic Service of the Air Force,