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4. The plan attached to title.--As before stated the plan does not in itself carry the information required to identify the land conveyed. I think it should do so, and should include:-
co-ordinates of corners,
lengths and bearings of lines,
area.
In any case should be plotted from original measurement at the same or at a larger scale whether the plan itself or the general map be regarded as the original. The dimensions and bearings should be those measured in the field, or, where bearings have not actually been measured the abbreviation "cal." (for calculated) should be arded. The exact procedure should be defined and included in the departmental regu- lations of which mention will presently be made.
I can see no valid reason for attaching more importance to a tracing than to a copy by camera, sunprint, or printing plant. Errors of copying by hand may be more formidable than those due to optical or mechanical processes. The real guarantee lies in the certificate of the officer responsible. The making of hand tracings is expensive if the plot is to be found properly surveyed and reproduced on some suitable large-scale
nap. Dimensions should, however, be added by hand.
5. Cadastral Maps.-The maps now being compiled at 50 and 200 feet to the inch (1/600 and 1/2,400) are the first to be reliable. The present programme envisages some 350 of the former and 50 of the latter (very roughly). The important areas of the Island and Kowloon are practically complete. The inception and progress of this mapping deserves special recognition, for when complete the series will provide a reliable record of alienation and will be of great administrative value. Undoubtedly the 1/2.400 plans should be printed and preferably the more important of the 1/600 A precedent lies in the 1901 plan of Victoria printed in six sheets by Messrs. Stanford and Co. There should be a ready sale for these plans and they should be made much more accessible to officials interested both in land and in technical develop- ment. The question of printing will be dealt with later.
too.
As soon as possible all antecedent plans covering the same areas should be removed from Government offices and destroyed except for record copies. Such plans are :—
(1) Plan of lots sold in 1844 (1/2,500 approx.).
(2) Plan at 600 ft. to the inch 1862.
(3) Plan of Victoria Hong Kong 1901.
The danger of using these inaccurate and misleading plans was exemplified in recent correspondence with the War Office.
Unfortunately the new plans are too large for easy reproduction (about 30 ins. by 48 ins.). The sheet lines should be rearranged before publication and an index to them should be made and printed.
The position in regard to the agricultural cadastrals is fairly satisfactory. There are, however, substantial changes in some of the areas, particularly in reference to resumptions by the Crown. More serious is the fact that they remain unconnected with the present triangulation or traverse framework. It is as important to incor- porate them in the system of measurement as to place each town lot in its correct relative position. The marks of the old traverse system on which they were originally surveved have wholly disappeared. The pencil
grid"
upon the originals refers to
an origin, and to axes, which are not those now in use. By triangulation or traverse at least three points in each cadastral should be fixed in the new system and the theoretical values of the old grid should be found (by computation) in the new. Examples of this calculation are to be found in Survey Computations" produced
C
by the War Office and printed by His Majesty's Stationery Office.
6. The Trigonometrical Survey. The efficiency of a Survey Department depends, first and foremost, upon the accuracy of the framework (triangulation and traverse) and upon good and accessible records of that framework.
Since 1922 the War Office have been in communication with Hong Kong for the correction of old maps and for the production of the new, accurate topographical map. We asked for copies of the records. We received a number of contradictory and baffling lists. Finally it seemed necessary to call for records of the original field measures from which to establish and adjust reliable positions. Even in the list of field measures we found anomalies. You are no doubt aware of the correspondence which has dealt with the matter.
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Investigation shows a state of affairs even more serious than had been imagined. No one presumably is responsible. The muddle arises from :-
(a) Lack of co-operation between civil and military surveys; (b) Lack of continuity in survey guidance and policy;
(c) Lack of room for the storage of records;
(d) Divided responsibility.
These points are dealt with in a subsequent paragraph, and in this one leal with the history and future needs of the trigonometrical survey.
፡፡
shall
As far as I can establish, Hong Kong and the New Territories have been trigono- metrically surveyed, either partially or wholly, three or four times. In the days of the Surveyors-General (who seem to have been the heads of a combination of technical and municipal services) no framework would seem to have been made. Some property surveys were good, some evidently bad, but all were
" and could not be floating put together except by graphic fit. In 1886 Lieutenant Collinson made what appears to be a good map of the Island. This map shows Trigonometrical stations, but all records of positions are lost. At the beginning of the present century we find Messrs. Tate and Newland (from the Survey of India) engaged upon property and topographical surveying under the orders of the Government. Almost contemporaneously, Major H. S. King was employed to make a military (or Ordnance, since it was to show boundaries of ordnance or War Office property, as well as topography for defence purposes) map at 8 inches to the mile. Both parties did much triangulation.
In a manuscript report of 31st August, 1900, Mr. Tate remarks:-" In a regular triangulation it is very necessary to mark permanently the stations
and in order to secure that this should be done
I have sent to the Public Works Department a list of all stations
with a request that it will arrange to place permanent marks ...
at as early a date as possible." Apparently in 1903, or later, some effort was made to comply, but the points had then been lost.
In all, Mr. Newland marked with clay cylinders about 4,700 traverse stations. Major King and Mr. Newlands used two bases and occupied about 50 Trigonometrical stations. Of these all the Trigonometrical stations save one or two, all records of hase measurements save the assumed final lengths, and all the traverse points save one or two in Kowloon are irretrievably lost.
Actually, I fancy, before the two Surveys I mention were complete the Public Works Department began to investigate, to observe and to compute a fresh triangula- tion. Quite recently the points have been permanently marked, but this triangulation rests upon the old bases (whose accuracy can only be established by remeasurement), and its records are hopelessly inadequate. For example, the original field books do not exist except in some few scattered cases. The original angles cannot be got even from the record of the solution of triangles, for these, in the majority of cases, are given as corrected"
angles (drawn from some partial and ill-advised system of adjust- ment). At the present moment there is even no one comprehensive diagram. There are two factors which are reassuring, however :-
(a) The whole figure has been carefully adjusted in blocks by the War Office, and appears moderately consistent. There is, however, no guarantee in this adjustment of the accuracy of the original scale (or base measurement). (b) The various small bases (three in number), although they may be of any order of precision, do agree as computed through the triangulation, and careful traverses do fit upon the trigonometrical positions to a sufficiently high order of precision (say average one point in six thousand). It is then possible that rapid deterioration, and propagation of error, has been stopped in time. A remeasurement of bases seems unnecessary.
There will now be a system of permanently marked points, and a printed record of lengths, angles, and positions. I am not sure exactly what the War Office intend to print. It may be assumed that the data given will include the figures chosen for adjustment, the corrections made to the original angles, the adjusted angles, and lengths and positions given in-
(c) Geographical co-ordinates (latitude and longitude).
(d) Rectangular co-ordinates upon the projection, and from the origin, used
for the new 1/20,000 map.
For the purposes of the Survey Department. there should also be a printed record of
(e) Rectangular co-ordinates from Victoria Peak.
Note. If the latter are not given by the War Office they must be compiled and
printed.
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