PANEL ON ARCTIC MAPPING 385

Kiely, Edmond K., Surveying Instruments.Their History and Classroom Use, New York,Columbia University, 1947.

Kimble, George H. T., Geography in the MiddleAges, London, Methuen and Co., Ltd., 1938.

Markham, Sir Clements R., The. Lands ofSilence. A History of Arctic and Antarctic Ex­ploration, Cambridge, University Press, 1921.

Shackleton, Edward, Arctic Journeys, Farrarand Rinehart, New York, 1936.

Finch, J. K., Our Indebtedness to the Old Sur-

veyors, The Military Engineer, Vol. XVII,No. 94, July-August, 1925, pp. 320-325.

Report of the Second Norwegian Arctic Expedi­tion in the "Fram" 1898-1902, Kristiania,Videnskabs-Selskabet, 1907.

Mirsky, Jeannette, To the Arctic, New York,Alfred A. Knopf, 1948.

Baker, J. N. L:, A History of Geographical Dis­covery and Exploration, London, George G.Harrap and Co., Ltd., 1931.

ARCTIC AIR PHOTOGRAPHY

PART 1

OPERATIONAL PROBLEMS IN ARCTIC SURVEY PHOTOGRAPHY

WIC R. I. Thomas, Commanding Officer, R.C.A.F. Station, Rockliffe, Canada

SYNOPSIS

Selection of areas:Supply of gasoline and oilClimate, the operational time-table

The weather:

Effect of open waterNeed for good forecastsWork of arctic weather team

Communications:

Part of weather forecasting systemNavigation aidsAircraft following serviceContact with supply bases

Navigational problems:

Low directional pull of magnetic poleEffect of local attractionsMap readingUse of solar navigator and astro compasses

Servicing the operation:

Remarkable results in spite of handicapsDetailed planning of sparesSafety training

Improvements since pioneering days

In my talk I will discuss the opera­tional aspects of Arctic aerial photographyunder the general headings of: s~lection

of areas, operating supplies, climatic condi­tions, navigation problems, communica­tions, and logistic support. WIC Ross, whowill follow me, will provide the technicaldetails of our Arctic aerial photographicproblems. .

Unlike planning of aerial mapping inmore developed areas, the selection ofareas in the Arctic involves an importantoperational' problem, because of the scarc-

ity of aerodromes suitable' for four-enginedaircraft. We have suitable landing stripsat Norman Wells, Yellowknife, Churchill,Whitehorse, and one in the Arctic islands.We do not build aerodromes in the Arcticspecifically for our photo operations; ourrequiremen ts therefore affect the main­tenance at aerodromes already estab­lished. The fact that aerodromes are un­serviceable for varying periods during thespring break-up must also be taken intoconsideration. It is apparen t then, that anyselection of areas must take into accounttheir accessibility from one of the existingaerodromes, and whether the aerodromehas sufficient su~plies of petrol and lubri­cants in stock to permit flying before thenext year's deliveries are made.

Provision of gasoline and oil is a majorproblem at such places as Yellowknife andin the Arctic islands, since the quantitiesrequired can be put in economically bysurface transport only. As transportationis by water, and as the season is veryshort, varying from approximately 4months at Yellowknife to 6 weeks in theislands, it is necessary to plan the supplyapproximately 18 months ahead of anoperation. If a substantial portion of theavailable stock is used for some emergency,it may necessitate changing flying plansfor the entire season. Such a case occurredat Yellowknife in 1951; an extensive searchfor a lost commercial pilot consumed some75,000 gallons of gasoline which were ear­marked for photographic operations.

Climatic conditions in the Arctic governthe operational timetable to a very greatextent. The best period of photo weather

386 PHOTOGRAMMETRIC ENGINEERING

is usually in the early spring, which on themainland comes in late Mayor earlyJune, and on the islands about the middleof June. We attempt to take advantage ofthis period of weather, provided the snowhas disappeared sufficiently for topo­graphical features to be identified. Gen­erally there is a period of two weeks be­tween the snow going and open water whenexcellen t photographic weather prevails.Once open water has arrived, work ishampered by clouds of various types.Over the mainland section, cumulus cloudsprevail, while over the islands a heavylayer of stratus forms over large areas ata time. Conditions can usually be forecastfairly accurately by the weather stationlocated at Edmonton specially to provideforecasts for the Arctic regions. With thelarge areas involved, and the great dis­tances from base to the operational areas,aircraft would waste a lot of time unlessfairly accurate forecasts were given.

It is well to clarify one common mis­conceptiop about Arctic aerial' photog­raphy, namely that it is carried out underideal weather conditions only. When it isrealized that these aircraft may range 700miles from their base to find clear weather,it will be evident that they must at timestake off and land under instrumentweather conditions.

Another common misconception in re­gard to Arctic weather concerns tempera­tures. While it is not uncommon to ex­perience temperatures below 32°F. inmidsummer in the islands, temperatures of75 to 80° also occur. It is surprising howmuch growth can take place during thelong northern days. At Norman Wells asmall plot of land has yielded as much as5 tons of vegetables in a season of three'months.

Without an effective communicationsystem, efficient photographic operationswould be impossible. Existing facilitiesare therefore supplemented by a specialsystem which broadcasts meteorologicaldata, provides navigational aids at thebases where necessary, and maintains con­stant touch with planes while they are onoperational fligh ts. Weigli t res trictionsmake it necessary to use high-frequencyequipment, and blackouts therefore causeconsiderable difficulty at times, but bychanging frequencies it is usually possibleto maintain con tact.

Navigation is the most difficult opera­tional problem in Arctic photo surveywork. Much of the area, both on the main­land and in the islands, is centered aroundthe Magnetic Pole, situated on Prince ofWales Islimd. In this region the magneticdirectional compass is of very little use,and other methods of maintaining direc­tion must be used. On all long-range Arcticflights, R.CA.F. aircraft employ gridnavigation, using an astro compass to cor­rect an electric or vacuum-driven gyroinstrument. The large magnetic variationwhich reaches 180 degrees in the islands, isthus eliminated. Grid navigation depends,for its accuracy, on a very accuratecalibration of the precession rate of thegyro instruments, and frequent checks bythe sun to assure that the aircraft is beingkept on course. For flying actual photolines, another instrument, called the solarnavigator, is used. This,instrument makesit possible to maintain the direction of theaircraft with extreme accuracy. It islinked to a gyro-stabilized drift sight, andby frequently correcting for drift thenavigator can maintain course.

Once the aircraft reaches the opera­tional area, the problem of locating itsposition by map reading faces the crew.The innumerable lakes and rivers on themainland in the Arctic and the many dis­crepancies in the maps of the islands makethis extremely difficult, and much ex­perience is required to correlate the mapsand the actual landscape.

Because of this problem, as well as tospeed up the production of small-scal.emaps, two types of photography-tri­camera and vertical-are used. The formertakes three photographs simultaneously,one vertical, one right oblique, and oneleft oblique; the machine flies at 20,000feet, and the cameras cover an extent ofcountry that makes. it possible to fly linessixteen miles apart. Experience has shownthat in tri-camera wor~, flights may bemade by dead reckoning with sufficientaccuracy to avoid gaps; it has also beenfound that accurate maps on a scale of 8miles to the inch can be produced fromthe photographs. These maps can then beused as a guide for the vertical photog­raphy, which uses one camera with a 93°angle lens. Verticals are taken at 20,000feet, with the lines of flight from 21 to 3miles apart.

·PANEL ON ARCTIC MAPPING 387

The need for such a procedure can be ap­preciated by considering one example ofthe type of errors found on previous maps.Kent Peninsula, which lies on the Arcticcoast of Canada about 650 miles east ofthe mouth of the Mackenzie River, wasshown so,me 30 minutes of longitude toofar west on certain maps. Since it was aprominent landmark which could be easilyidentified, and was therefore used as acheck point, serious mistakes in navigationwould result 'from such an error.

Even with the improved maps securedby use of tri-camera photography, navi­gators need a great deal of training beforethey can produce acceptable results. Themass of lakes on the Arctic mainland andthe configuration of the Arctic islandsmay easily confuse the inexperienced navi­gator.

Royal Canadian Air Force policy speci­fies that the aircrew should be trained inall types of operations, and a limit of threeyears has been set for training in anyonetype of squadron. Training is a majorproblem: we lose one-third of our personneleach year, and as the squadrons are onoperations during the summer, trainingmust be carried out in winter, when thesnow-cover.ed terrain presents a totallydifferent appearance, and many featuresare obscured. Javigators, therefore; mustlearn map-reading largely on actual op­erational flights.

In addition to the need for technicaltraining, a certain mental attitude has tobe developed in pilots and crews for Arcticw!"rk. Because of much misconception andlack of knowledge, green crews are apt toturn back at the slightest sign of anythingabnormal about either their aircraft or theweather when flying in the Arctic. We tryto offset this tendency by giving survivaltraining which involves spending twoweeks in the open in mid-winter. After alittle experience the crews carryon as ifoperating anywhere else in Canada.

Servicing planes in the Arctic in summeris very much the same as in detached op­erations· in other parts of Canada. Theequipment used must be portable, andsuch items as hangar cranes and similarequipment must be dispensed with. Whatmakes the problem'more acute in photo­graphic operations is' the fact that thecrews are away from a main base. for so

long at a time. With the concentratedflying that is necessary to take advantageof the short season and the long days,maintenance is carried out on a 24-hourbasis during good weather. In spite of thehandicaps of working outside without shel­ter in dust and wind at temperatures oftennear freezing point, some outstanding re­sults are achieved. On one occasion anaircraft stranded in the islands had anengine changed between 10: 30 P.M. and6: 30 A.M. and then flew some 2,000 milesof photo lines the same day. The continu­ous daylight helped of course, but a 15m.p,h. wind at 34°F. made work in theopen extremely uncomfortable.

One of the major difficulties in Arcticservicing is the supply of spares. Althoughlarge quantities of spates, based on pastexperience, are taken up, it is simply im­possible to provide against all contingen­cies, and a season seldom goes by withoutsome shortage developing. In such cases itis considered well worth while to fly thenecessary parts in from outside, in orderto take all possible advantage of the veryshort season of good flying weather which,in at least one case, amounted to threedays only.

While all the problems in Arctic photooperations are not yet solved completely,we have progressed a long way from thepioneering aspects in which Canada hasplayed so great a part. From the days ofmulti-oblique photography from the open­nose cockpit of a Vickers Vedette FlyingBoat doing 70 m.p.h. at 5,000 ft. to tri­camera and vertical photography at 250m,p.h. and 20,000 ft. is a long step. Thatsuch a step has resulted in the presentlevel of efficiency is due in very largemeasure to the effective and devoted workof the earlier pioneers.

The major problems in Arctic flying aredue to climate, lack of navigational aids,and difficulties in supply and servicingarising out of the remoteness of the area.In future operations, such problems shouldbe greatly simplified by improved maps,the installation of radio aids, and the de­velopment of improved directional instru­ments. It is possible that even the climaticproblems may ultimately be overcome toa large extent by the improvement ofradar photography, which has already pro­duced some striking results.