MOUNT EVEREST MOUNTAINEERING BOOKS
Recently discovered at the Royal Geographical Society is the 1939 Michael Spender map of the Environs of Mount Everest where it has lain un-recorded for more than 50 years. Although now finally scanned it remains unpublished - but this hopefully will be resolved in 2012.
The Photo-Surveyed Maps of The Mount Everest Region and Nyönno Ri
The photographic surveys of the 1935 Reconnaissance Expedition to Mount Everest were plotted in Switzerland in February 1939 at the Wild factory in Heerbrugg. The work was done at the direction of the Mount Everest Committee; the principal object was to plot the map of the Mount Everest Region. Fortunately, however, Mr. Shipton was able to accompany me for a short while, and with his help and with the valuable assistance of the firm's engineer, Mr. Vögeli, who was enthusiastic about any aspect of the work, it was possible for us also to plot the photographic survey of the eastern face of the Nyönno Ri and the country near Sar. Not only was this (a) comparatively extensive programme of plotting between the 16th January and 15th February, but Shipton also learnt to plot, and then plotted his own photographic survey, made in 1938, of part of the western flank of Nyönno Ri.
The results obtained from this short sojourn in Switzerland are a reminder of the grave handicap exploratory survey suffers in England on account of the absence of any institution capable of dealing with such photographic surveys.
The field-work of these surveys is described respectively in my paper 'Photographic Survey in the Mount Everest Region' (Geographical Journal, vol. lxxxviii, no.4 Oct. 1936, p. 289) and in an appendix by Shipton to Tilman's paper 'The Mount Everest Expedition of 1938' (Geographical Journal, vol. xcii, no. 6 Dec. 1938, p. 487). The survey of the north face of the mountain had already been plotted and published, first in a preliminary form in my paper mentioned above, and then in a more complete form, together with another account of the work, in the Himalayan Journal, vol. ix, 1937, pp. 16-20, map p. 126, and in Mr. Ruttledge's book Everest: The Unfinished Adventure, describing the 1935 and 1936 expeditions. Reference should be made to these papers for accounts of the technical and circumstantial difficulties of these surveys. Our work of two years later in the Karakoram seemed like a summer holiday in the Alps when compared with the difficulties peculiar to the Mount Everest region. The discussion that took place at the end of the earlier paper, describing the condition of photographic survey in England in May 1936 applies with equal force in March 1939.
The position at the beginning of January 1939 was that the framework for plotting had been prepared for the eastern half of the Mount Everest survey. This existed as a plot on the scale of 1: 50,000 on Correctostat paper. It had been possible to lay this plot down with some sureness on the basis of a preliminary plot started in the Rongbuk valley which showed that certain of the available fixed points were badly out of position (cf. Himalayan Journal). In particular Kharta Changri and the so-called ‘Dent Blanche’ were erroneously given in the G.T.S. pamphlets. The present plot is based in position and height on Mount Everest, Makalu, and ‘Kellas’. The resulting heights, which are reliable, have a general tendency to be some 100 feet higher than Wheeler’s determinations.
Before proceeding to Switzerland on the 15th January as much progress as possible was made with the re-plot of the Rongbuk valley and the whole survey was transferred to a large sheet of mounted cartridge paper. The Sar survey was also plotted by Mr. Milne at 1: 100,000 on a large enough sheet to allow room for Shipton’s survey and any further work which may be undertaken by future Mount Everest expeditions.
The photographs to be plotted had been made with two cameras of differing focal lengths. The Royal Geographical Society’s Wild photo-theodolite had been used in the Rongbuk valley, while in the remaining areas the camera belonging to the Danish Geodetic Institute, converted by Zeiss at my suggestion to use film, and kindly lent by Professor Norlund, had been used on account of its lighter weight. The two instruments had focal lengths respectively of 161.14 mm. and 139.10 mm.; the areas photographed to some extent overlapped. It was for us a matter of the greatest convenience that since the expedition set out a plotting-machine had been developed by the firm of Wild which permitted an instantaneous change from the value of one camera’s focal length to that of the other. It was also an advantage that we did not have the expense of making special plotting-cameras, since it was not to be expected that a plotting-camera for the Swiss lens would be found in Germany, or vice versa. This property of the Wild Autograph A5 allowed us to work casually from film to plate and plate to film exactly as the convenience of plotting suggested and entirely without reference to any instrumental idiosyncrasies. It will be recalled that in the A5 the ray-paths are embodied by steel rods and the plotting-cameras have no lenses.
The progress of the plot revealed the following points:
1. The underlying plot in plan and height was completely reliable.
2. The film photographs, which in my paper I referred to as being somewhat flat in quality, were in fact excellent to work with, as it was possible to plot on both rock and snow. The film (Perutz Topo emulsion specially prepared on a base of Fliegerfilm) was of an extremely fine grain; there appeared to be no errors arising from irregular distortion of the film; and altogether it was pleasanter to work with the film negatives than with the plates.
3. No difficulties arose from the plates having been rather badly scratched during transport.
In general, the plot emphasized to Shipton and me the progress made in co-operation between climbers and surveyors. With the experience we both now have, the work might have been planned a great deal better. In many cases the Watts-Leica instrument could have been used then, or even in 1936 or 1938, to support the stereo-survey; in other cases the panoramas taken by the climbers with hand-cameras might have been better planned and more complete. As it is, valuable rounds of photographs from commanding points are often restricted to the picturesque or imposing section of the view. A clear example of work badly carried out is to be seen at the foot of the Khartachangri glacier, where there is a comparatively small area, liberally surrounded with fixed points and yet unsurveyed, although it was traversed by a party of four climbers.
From the technical point of view the plot shows that since film has been introduced into exploratory survey technique, there are no effective arguments left in favour of the use of plates. The transport difficulties, the use in the field, and the risks of breakage all speak strongly against the use of plates. There is in fact no point at which the plate is superior to the film in terrestrial photogrammetry. Nevertheless, there is at present no satisfactory photo-theodolite on the market using film. From the specialized point of view of the exploratory or mountain surveyor it is urgently necessary that this gap be filled.
Plotting was done in both areas at 1:50,000 with contours at 250-foot intervals. The Mount Everest area was about 350 sq. km. and the Sar area about 450 sq. km. In the first area plotting went forward at about 25 sq. km. per day: in the second at about 45 sq. km. per day. The figures are very approximate, but offer some guide to later work. The filling in of the Mount Everest sheet by single picture photogrammetry from photographs taken in 1935 as well as during other expeditions demanded considerably more time than that required for the stereo-plot. Four weeks were spent on this work and the inking in of the sheet.
M. S.
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