INTRODUCTION 
The /nternational Archives of Photogrammetry, Volume XXI, a record of the proceedings and results of 
the XIII Congress of the International Society for Photogrammetry held in Helsinki in 1976, is now 
ready for distribution to all interested in the theory and practice of photogrammetry and other remote 
sensing techniques. 
In 1972 the General Assembly of the Ottawa Congress decided to entrust the organizing of the XIII 
Congress of the ISP to the Finnish Society of Photogrammetry. It was Professor Reino Sakari Halonen, 
Head of the Institute of Photogrammetry at the Helsinki University of Technology (HUT), who had the 
courage to undertake organizing this congress in Helsinki. We are greatly indebted to him for his 
thorough preparations for the congress which, at his sudden death in the summer of 1975, made it 
possible for us to go through with the congress in the original spirit. The aim of the organizers was 
to make the best of the premises offered by the HUT with its campus in Otaniemi, so as not only to 
provide efficient and flexible congress arrangements, but also to create a warm and pleasant atmosphere. 
To make known the congress, the following trilingual publications were sent out: Preliminary Program 
in 1975; Congress News Letter Nos. 1—4 between 1974 and 1976; Procedures for Commission Activities 
and Publications in 1975. 
To create fruitful discussions at the technical sessions a special Advance Distribution of Papers and 
Abstracts was arranged, giving the participants interested an opportunity to study the relevant 
publications beforehand. 
Well aware of the decisive role played by the commercial exhibitors in making the congress a success 
both technically and economically, the organizers set out to improve their possibilities of communi- 
cating with congressists by arranging an Exhibitors' Forum. 
At the Helsinki Congress, the ISP acquired an emblem of its own. The Congress Committee, with 
the approval of the ISP Council, had a flag made and donated it to the ISP for use at its congresses. 
The flag is white with the symbol of the ISP in blue. 
The compilation of the Archives is traditional. The minutes of the Plenary Sessions and General 
Assemblies are given in the form approved by the President of the ISP. The deliberations of the 
Technical Commissions are given as condensed reports of the proceedings in the form delivered by 
the Commission Presidents. For the sake of uniformity, additions based on the tape recordings of the 
sessions have been made in certain cases. 
The trilingual abstracts of the technical papers received by the secretariate had to be checked as to 
their language and the missing translations had to be provided before publication in the Archives. 
Several foreign institutes and private persons that we turned to through the Commission Presidents 
have given us valuable help in accomplishing this comprehensive work. The Presented Papers, of 
which only the abstracts are included in the Archives, in seven binders, form a separate publication 
entitled Presented Papers of the XIII ISP Congress Helsinki 1976. 
We whish to thank all our countrymen who took part in the versatile congress arrangements and, first 
and foremost, all ISP officials, exhibitors and congressists who through their active participation and 
understanding greatly contributed to making our congress successful. Finally we want to extend our 
warm thanks also to all those who have kindly helped us to fulfil our post-congress obligations. 
INTRODUCTION 
Les Archives Internationales de Photogrammétrie, Volume XXI, un compte-rendu des délibérations et 
des conclusions du treizième Congrès de Photogrammétrie qui s’est tenu à Helsinki en 1976, sont 
prêts pour la diffusion à tous ceux qui s’intéressent à la théorie et à la pratique de la photogrammétrie 
et aux autres techniques de la télédetection. 
L'Assemblée Générale du Congrés d'Ottawa, en 1972, a confié l'organisation du XIII Congrès de la SIP 
à la Société Finlandaise de Photogrammétrie. Ce fut le Professeur Reino Sakari Halonen, Chef de 
l'Institut de Photogrammétrie à l'Ecole Polytechnique de Helsinki (EPH), qui se chargea d'organiser 
ce congrés à Helsinki. Nous lui sommes fort redevables de ses minutieux travaux de préparation du 
congrés. A sa mort soudaine en été 1975, gráce au travail déjà accompli, nous pümes réaliser le 
Congrés dans son esprit original. 
Le but des organisateurs fut d'utiliser au mieux le site remarquable mis à leur disposition par l'EPH 
sur le campus d'Otaniemi, non seulement pour offrir des arrangements souples et fonctionnels au 
Congrés mais aussi pour créer une atmosphére agréable et chaleureuse. Pour faire connaitre le 
congrés, les publications trilingues suivantes furent envoyées: Preliminary Program, en 1975; Congress 
News Letter Nos 1—4 de 1974 à 1976, et Procédures pour les activités et publications des Commissions 
en 1975. 
Au cours des sessions techniques, la discussion organisée constitue le moyen le plus efficace pour 
transmettre l'information récente. En outre, tous les participants actifs doivent avoir eu la possibilité 
d'étudier à l'avance les publications relevantes de la discussion. Dans ce but fut organisée une pré- 
distribution spéciale des documents.