The following advantages could be mentioned. 
Initial investment for these projects in the photogrammetric method was insignificant, 
since it was not necessary to form new companies nor to increase the equipment available; 
it was merely necessary to use existing facilities. As a contrast it should be remembered 
that with the use of land methods they had to organize 1,200 crews. 
— One should neither expect the fulfilling of any previously specified time period, since one 
can always begin the projects by utilizing corrected photographic mosaics which can be 
found in official, as well as, private, files. 
— (3) COMBINATION OF METHODS. This system consist of the most adequate utilization 
of photogrammetric and land methods, making use of the relative advantages in each 
case. 
By analyzing the different alternatives, it was concluded that one should use a combi- 
nation of these, with special emphasis on photogrammetric surveying and to complement the- 
se, where small surfaces were concerned, with land methods, especially in remote re- 
gions where the taking of photographs would be difficult. 
On the other hand, it was concluded that the most adequate scale was 1:20 000 on 
the mosaic since this would allow the identification of the necessary details to locate 
those land properties, and at the same time it was concluded that this scale was large 
enough not to increase the cost of the study. 
It should be pointed out that the Department of Agrarian Affairs and Colonization got 
in touch with the following government enterprises: 
— National Defense Ministry. 
— Agricultural and Animal Husbandry Ministry. 
When it was decided that the projects should be carried out through photogrammetry, the 
Department of Agrarian Affairs organized their own Bureau of Photogrammetry, a dependen- 
cy of the General Secretariat of the New Centers of Common Land Population. The research 
crews have been dependent since that date cf the Coordination and Supervision Bureau of the 
National Agrarian Program. 
IV. STUDY PLAN 
Having considered it convenient to adopt the combined system, with special emphasis on 
photogrammetric features, the elaboration of a study plan was started, under which survey- 
ing and the finding out of land tenure were carried out. It should be brought out that all 
those creas which already had photogrammetric surveys did not need the first step already 
mentioned. 
A) Photogrammetric projects. 
Flight plans and the carrying out of the photographic missions. 
The compiling of data and ground control. 
The carrying out of complimentary ground control. 
The making of rectified mosaics. 
a) Aerial triangulation and radial triangulation. 
b) Rectification of the photographs. 
c) Gluing the photos and touching up of the photographic mosaics. 
d) Reproduction and touching up of the negatives. 
e) Making of photographic mosaic indexes. 
f) Making of photographic copies. 
B) Land tenure. 
A ON — 
1. Delimitation of public and communal land at the office. 
Examination in the office of the remaining property of land to find out those which 
go over the maximun area allowed by the law.