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The contribution of aerial photography to the development projects in UAR

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Distr.*

LIlHTED

E!CN.14/ CART/74 E!CONF.43!74

1 July 1963

Original ENGLISH ,.

U\NfTED NATIONS

ECO~JOMIC

AND

. SOCIAL COUNCIL

UNITED NATIO}TS REGIONAL CARTOGRAPHIC CONFERENCE FOR AFRICA

Nairobi (Kenya) 1-13 July 1963 Provisional agenda item 13(b)

DOCUMENTS OFFICE

NO TO RE TAKEN OUT

THE CONTRIBUTION OF AERIAL PHOTOGRAPlrY TO THE DEVELOPMENT PROJECTS IN UAR

(presented by the Government of the United Arab Republio)

* For partioipants only

NAI-63-30

/'

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UNITED NATIONS REGIONAL CARTOGRAPHIC CONFERENCE FOR AFRICA

Nairobi (Kenya), 1-13 July 1963

II

EGYPT, U

ARI

THE CONTRIBUTION OF AERIAL PHOTOGRAPHY TO THE DEVELOPMENT PROJECTS IN UAR

by

Eng. MOH. A. F. MOHSEN

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Introduction

In the past ten years the increasing dangers of over-population and its effect on economic development was felt to be a real problem all over the whole world. This problem has to be solved in U.A.R. by speeding up the de- velopment of the reserves and raw materials, carrying out land reclamation projects, improvements in the field of agriculture and maximum utilization of raw materials. Without maps it is impossible to carry out any study con- concerning projects developments. Aerial photographs are the most economi- cal and efficient means known to us at present for preparing topographic, soil, geological maps.

General application of aerial photography.

In recent years aerial photographs have become extremely important for soil survey purposes and I believe that one of the essential repuirements to suc- cessfully perform soil survey is good aerial photography at a suitable scale. The soil map can be produced showing the distribution of various soils occurring in a particular area. There are several types: detailed, semi-detailed and recon- naissance. They serve different purposes in particular those of land reclama- tion, and selection of suitable areas for agriculture.

The aerial photograph is a valuable aid for location and preliminary plan- ning of roads, railways, new cities and villages. After being supplied with elevation points it may aid in preliminary location of canals, in addition it can be used for determining shore lines, drainage lines and swamps.

In geological field the aerial photographs speeds up and facilitates pros- pecting in different parts of the country and some few examples will be given later to illuslrate how helpful can be the aerial photographs in this connec- tion.

An important role of aerial photographs is producing topographic maps.

Photogrammetry is the branch of science which deals with converting aerial photographs to topographic maps. There will be a slight discussion con- cerning this item when analysing the different aids of aerial photographs to the new valley project in U.A.R.

The major projects in U.A.R.

THE HIGH DAM

This dam which is constructed in Upper Egypt to the south of Aswan is considered to be one of the biggest dams in the world.

One of the benefits of the project is to increase the present cultivated land in U.A.R. by about 30 0/0. The first problem which existed was how to carry out very quick reconnaissance soil survey to make selection for the suitable

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area to be cultivated. For this purpose a semi-controlled masaic at a scale

1 : 50000 was constructed. It covered a total area of about 20 million feddans I

lying in the desert fringes of the Nile valley and in the coastal belt of the Nile Delta. A reconnaissance soil survey and semi-detailed one for an area of about II million feddans was carried out and revealed the suitabililty of 650,000 fed- dans till now.

The preliminary investigation and study of the site of the dam was carried out by the help of 1 : 25000 scale topographical maps with 5 meters contour interval prepared from wide angle photography.

BAHAR YIA-HELW AN RAILROAD

After the discovery of iron ore in Baharyia area, there was the problem of finding a means for carrying the ore to the steel works and this problem has been solved by carrying out a feasibility study and preliminary design of the rail- road to be constructed between the terminal points. Two general routes were studied : -

(a) The direct road from Baharyia oasis to Cairo.

(b) The route due east to meet the river Nile.

The execution of the work continued according to the following steps : - (a) A reconnaissance survey of the entire area between terminal points to

define in general the possible railroad routes locations, controlling topog- raphic features, soils and rocks according to their engineering characteris- tics, geology and drainage. The reconnaissance had been carried out by traversing the region with vehicles and aircraft and this went side by side with a stereoscopic study of small scale aerial photographs. The results of the previous study were keyed to a controlled masaic at a scale 1:50000.

(b) A reconnaissance of alternative routes was carried out and for this pur- pose a stereoscopic photo coverage with aerial photography at a negat- ive scale of 1 : 50000 was executed. The aerial photographs covered the chosen strips which were of approximately 15 km. wide along the alter- native routes of the railroad. A precision camera with 6 inches focal length lens and 9x9 inches format had been used. The forward overlap was nominally 60% and the side lap was 300/0.

(c) A detailed reconnaissance for the selected route was the expected ef- fort to be worked out and it was necessary to compile topographic maps at a scale I : 10000 with contour lines at 8 meter interval with inter- mediate form lines at 2 meter interval. These maps have been compiled from aerial photographs at a scale 1 : 50000, the instrument used for this purpose was the Kelsh plotter. Besides a photo interpretation study had been carried out for soil, location of sand dune areas, cons-

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truction materials for embankment, aggregate and ballast. All this in- formation was plotted on the 1 : 10000 topographic maps.

(d) Preliminary design was executed. The preliminary centre line was projected with kilometer stationing, angle of intersection of tangents and the degree of curvature of each curve.

A centre line profile was drawn at I: 10000 horizontal scale and 1 : 500 vertical scale to show the percent grandients of the line, structure of sand dune crossing area and soil conditions.

(e) To make an estimate of quantities the preliminary cut and fill grading quantities was computed by an electronic computer.

The number, length and spans of drainage structures and bridges were estimated.

As a coclusion it was felt that the combination of photogrammetry and electronics has made it possible to carry out precise measurments and perform computations much more economically than by ground survey and conven- tional computation methods.

Application of aerial photographs to geological mapping and mineral resources surveys

The use of aerial photographs to assist and accelerate geological mapping was pioneered in U.A.R. by the geological survey and mineral research depart- ment in late 1956. Near vertical photographs at a scale of 1:20,000 and 1:40,000 taken by the 6 inches aviogon lens were used.

The interpretation of the aerial photographs resulted in : (a) Facilitating prospecting in different parts of the country.

(b) Refining pre-existing geological maps previously carried out by conven- tional survey methods.

(c) Tracing the upper cretaceous formations that contain phosphate deposits at Nile valley, Western desert and this work had been executed with greater accuracy from aerial photographs.

(d) It was possible through photo interpretation to locate outstanding shear zones that contain copper, lead zinc deposits in the eastern desert.

(c) Field parties working at desert regions did valuable work in tracing and directing prospecting for iron ore deposits by using aerial photo-

graphs.

(f) Coal bearing units were followed very easily through examination done by geological parties on aerial photographs.

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THE NEVV VALLEY PROJECT

It is one of the major projects which is very much interesting to the people in UAR...

The reclamation of the new valley comprises:

I. - The careful study to check the suitabitity of an area of about 3.5 mil- lion feddans to be cultivated, andto make all preparations to cultivate the selected areas with the help of the underground water.

2. - The construction of towns, villages and buildings.

3. - The discovery of iron ore, granite and phosphates.

To go on with such kind of work the specialists, experts and engineers in U.A.R. were in great need of as much information on the characterization of the major soil areas and some more information that would be helpful in making general plans for future development of agriculture and the utilization of water and other resources and which will also be of value in road construction, town planning and other engineering projects. Good soil, geological and topographic maps must be at hand to facilitate the work of our experts.

In a vast area like the new valley which is of great economic interest all kinds of maps can be obtained by air photo-coverage and in this connection I do believe that an important role is played by the superwide-angle photo- graphy.

An entire area which consists of about 223000 square kilometers was pho- tographed by using the super-wide angle lens with about 88 mms. focal length at a scale of 1 : 50000 the forward overlap was about 60010 and S.L. 30010, the flight was due north-south and the total area was covered by about 6500 photographs and controlled masaic at a scale of 1 : 100,000 was constructed.

A reconnaissance soil survey was conducted for the whole area. The soils were examined, described classified in the field and delinated on the contact prints in the office with the aid of a scanning stereoscope. After delineating the natural features such as soils, stream courses and peaks and. cultural features such as desert tracks, temples and wells on the aerial photographs at a scale of 1 : 50000, the soil delineations were transferred from the aerial pho- tographs to the controlled masaics.

Magnetic profile lines were completed totalling more than 9000 miles with flight altitude of about 500 ft. Line spacing and bearings were determined on the basis of using lines one mile apart in pairs spaced about 30 to 40 miles I think that preparing the topographic base map sheets for the area under development from the ultra wide-angle photography is somewhat interesting.

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The various available instruments for the direct plotting of super wide- angle photography are wild A9, B9, B8, some types of multiplex projectors and approximate instruments like the stereotope. If no equipment was available for the direct plotting of super wide-angle photography, existing instruments may be used for affine plotting where topographic maps can be made with the required accuracy by means of the affine plotting technique if W = Q= 2g and this can be obtained with the aid of gyro-stabilized cameras.

The aerial triangulation can be carried out on the A 9 machine and if LB.M. electronic computer is combined to the photogrammetic technique then the strip adjustment through this channel will gurantee rapid progress of the work while maintaining the required acuracy both in horizontal and vertical,

otherwise a block adjusment with Jerie method will be successful.

In this connection I believe that if we take advantage of the new deve- loped equipments and techniques for distance measurrnent with the aid of electromagnetic waves (like the tellurometer) or with high-frequency modulat- ed light (as in the case of the geodimeter) then we will reach a very good eco- nomical solution for the problem of field work.

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