Imperial Japanese Geodetic Survey, Mapmaking,Maps: In context to Ph. T. Hunting

[Janner]

I would surmise that not many of the so called members will read this,
 far to "In Depth" for them to take in. How ever there is a few that will and they will benefit from this.
 Good reading and leading to a finale i assume...??

(i still have my "L1A1" Theodolite too)

[Ben Valmores]

To shed light on the methods, tools, bodies, and rhetoric employed by the Japanese state in its effort to produce cartographic knowledge of its colonies, an analysis proceeds in four phases,

beginning with a broad overview of the planning process undertaken by the Provisional Land Survey Bureau (Rinji tochi chosa kyoku; hereafter Land Survey Bureau)

This overview provides a rough sketch of the triangulation survey as it fits within the larger cadastral survey project.

Second, the article describes the methods and tools employed by the surveyors, and traces in broad strokes the progress of the survey from its commencement to its closing.
A third section explores the physical construction of the maps,
 
while the concluding section considers the limitations and lacunae of these maps and, more generally, the relationship between mapping, knowledge, and power in the colonial context.

For the government-general, the land survey was thus the key to unleashing the productive power and standardized maps—those that fashioned order out of perceived chaos.

[Ben Valmores]

oppss sorry double posting....

Yes Janner, we'll try to reach finale...

[t_hunter44]

as well as this line,

Statistics, blueprints, ethnographies: all formed building blocks upon which Japan’s civilizing mission would be constructed. Maps were no different. Cloaked in the mantle of scientific precision, the *triangulation survey showcased Japan’s superior methods.

*It never ever said it is Isometric Survey, from where in the world does NS got this term in context to treasure hunting? my rods says might be from a rhyme of his first name?

      TRIANGULATION was  supposed to be the proper word but NS like to use fancy or more technical words so he used Isometrics not knowing that some of us has had Engineering Drawing 101 and Isometric Drawing was a part of it. Three Dimensional Object and one can project the Top View, Side View and Back View. Well, he paid for his mistake as a lot of Flak was thrown his way. Glad to see that no one is pursuing the Topic about Isometrics as it was a Misnomer anyway, not even him. There is no point in rubbing salt to old wounds, let it lay.

[Ben Valmores]

yeah it's a misnomer but somehow it's also his superimposition of his Isometric plates on every maps presented to him, to fit his own interpretations and "solutions".

It's like a fit-any-maps "solution"

But ok whatever we should lay it down now....

[Ben Valmores]

Sub-categories of the major classes provide more insight into the various fields of surveying as follows:

·   Property surveys determine boundary lines, property corners, rights-of-way provide data necessary for the preparation of land sub-divisions.

·    Cadastral surveys are executed by the Federal Government in connection with the disposal of vast areas of land known as the public domain.

·    Route surveys are necessary for the design and construction of various engineering projects such as roads, railways, pipelines, canals and powerlines.

·    Industrial surveys, or optical metrology, are used in the aircraft and other industries where very accurate dimensional layouts are required.

·   Topographic surveys are performed to gather data necessary to prepare topographic maps. These are multicolour contour maps portraying the terrain; and rivers; highways, railways, bridges and other man-made features.

·    Hydrographic surveys map the shorelines of bodies of water; chart the bottom of streams, lakes, harbours and coastal waters; measure the flow of rivers; and assess other factors affecting navigation and water resources. The sounding of depths by radar is involved in this type of survey.

·   Mine surveys determine the position of underground works such as tunnels and shafts, the position of surface structures and the surface boundaries.

·    Aerial surveys use photogrammetry [/b]to produce a mosaic of matched vertical photographs, oblique views of landscape and topographic maps drawn from the photographs.

·    Construction surveys fix elevations, horizontal positions and dimensions for construction projects.

·    Control surveys provide basic horizontal and vertical position data. These are called datum. For most surveying work the vertical position of points in terms of height above a curved reference surface is mean sea level.

Surveying Techniques

1. Triangulation

2. Trilateration

3. Traverse

4. Leveling

5. Radiation

[Ben Valmores]

TRIANGULATION :

 the horizontal control in GEODETIC SURVEY is kept by precise traverse or triangulation.
"The system consist of a number of connected triangles in which the length of one side called "base line" and angles (azumiths) are measured precisely.As by knowing length of one side and all the three angles,the other sides can be known easily."

The apex of each triangle is called "TRIANGULATION STATION" and the whole system is known as "TRIANGULATION SYSTEM".

Image 1

Triangulation

Triangulation consists of a series of connected triangles which adjoin or overlap each other, angles being measured from determined fixed stations. Triangulation reduces the number of measures that need to be taped and for this reason is often a preferred method of survey. A known base-line measurement is required. Three examples of triangulation systems are shown below.
 
A single chain of triangles is a rapid and economical system for covering a narrow strip of land. A chain of quadrilaterals is more accurate with checks being made by various combinations of angles and sides as the survey proceeds. Larger areas use a central point arrangement. A point to note is that all angles should be more than 20°. Angles less than 20° are not considered valid for fixing position. They introduce inaccuracies. This is much the same in navigation where a fix by two bearings requires an angle of intersection of approximately 90°, and for three bearings approximately 60°. Angles less than 30° are not acceptable.
 Image 2

[Ben Valmores]

For the government-general, during colonial Japan times, (this one specifically in colonized Korea)

 
The land survey was thus the key to unleashing the productive power and standardized maps—those that fashioned order out of perceived chaos.

No single individual contributed to the day-to-day management of the cadastral survey more energetically than Tawara Magoichi (1869–1944), the career bureaucrat appointed vice president of the Temporary Land Survey Bureau in 1910 and later the director of its operations.

Tawara was soon joined by a cadre of surveying experts from Japan’s Land Survey Department (Rikuchi Sokuryobu), many of whom had cut their teeth mapping other parts of the Japanese empire. According to the official account, these surveyors “brought years of experience” (tanen shigyo no keiken o yu shi) and “progressive” surveying techniques (saishinpo seru mono) with them.

A small group of Korean surveyors, many of whom were involved in the ex-Korean government’s Kwangmu land survey (1898–1903), were also folded into the operation, as were fragments of the organizational and operational infrastructure of this earlier surveying enterprise. (Gragert 1994).

Although secondary to the cadastral process, the triangulation survey was nevertheless a vital part of the work of the Land Survey Bureau. Without maps fixed to a grid of longitudinal and latitudinal coordinates, Japan’s efforts would remain detached from the geodetic grid of the international system, yielding maps not only of questionable accuracy but also utterly unimpressive by international standards.

An abstract political goal, the process of triangulation provided the means to, quite literally, do just that. On a more practical level, the triangulation survey also provided the broader picture for surveyors and administrators alike: the base layer of spatial measurements against which more specific calculations (such as the cadastre) could be referenced.
 
“Based on the process of triangulation,” stated a report on the triangulation process, “the survey can schematically render land form and composition,” making it possible for these surveyors to enhance the cadastral process and reduce error considerably.

Both projects, in other words, were entwined: while cadastral investigators worked their way systematically from hamlet to hamlet and property to property, demarcating the boundaries and valuation of fields along the way, the geodetic survey section carried out a painstaking series of measurements to enable the consolidation of these individual plots onto one systematic spatial grid.

The early institutional composition of the Temporary Land Survey Bureau nicely reflects these twin cartographic imperatives. As of 1911, the bureau was comprised of 835 individuals of which 678 were engaged chiefly in land surveying: one as the chief surveyor, ten as inspectors, four as expert surveyors, and 661 as assistants (Unno 1997, 66).

It consisted of four primary sections: a general affairs section, which oversaw the political and administrative work of the survey; an investigation section, which conducted cadastral fieldwork; a survey section, which was charged with the production of maps through a variety of methods; and the land survey detached offices, which essentially served as local branch offices and data processing centers for the entire enterprise, A 1911 government-general report describes the division of labor as follows: “While the investigation section principally deals with investigating matters concerning ownership, location, boundaries, and also the compilation of reports of investigations, register books, etc., the survey section is charged with carrying out surveys by primary triangulation, secondary triangulation, plat survey and other measurements of lands, and with compiling maps of the districts surveyed” (GGK 1911, 42).

The Land Survey Bureau had also by this point established a small number of training schools where it undertook the recruitment and training of Korean and Japanese surveyors who would contribute to the survey in myriad ways.

[Ben Valmores]

The Surveyor’s Fieldwork

To monitor the planning, commencement, and implementation of the land survey:
….the first step in the sequence of the survey is the establishment of signal stations between two areas in order to establish baselines (honsen) that will connect with….signal stations already established in the vicinity.

 Surveyors, who number approximately 160, will break into twenty smaller parties, five of which will oversee the preparation and collection of land registers while the other fifteen, comprised of roughly 100 members, will undertake a detailed investigation (shosai no chosa) of these land plots.

Official documents on the movements of the triangulation surveyors are fragmentary, but a patchwork of government-general reports and the research of Japanese and Korean scholars provides a rough sketch of their earliest activities.
 
One of the first actions of the triangulation survey was to establish a geodetic linkage between Korea and Japan by way of Tsushima, an island that sat squarely between the peninsula and the archipelago. Stated a government-general report from 1910:

In order to connect the geodetic triangulation of Japan proper with that of Korea, based upon the selection of principal points of triangulation in Tsushima island, Japan proper, the longitude and latitude of Zetsuyei (Chyolyong) island (near Fusan) and Kyosai (Kö-jyö) island (near Masan) in the extreme South of the Peninsula, and the distances between the two islands were surveyed.

Dryly technical though, this statement might sound, it is hard to overstate its importance. As one of the first measurements taken by the surveyors, this geodetic linkage marked a critical step in Japan’s effort to orient Korean space to the same spatial matrix as the Japanese homeland, and thus into alignment with Japan’s own cartographic conventions.

So it was that the former trading post of Tsushima became a cartographic linchpin of the Japanese empire.

Note: This is my proof that somehow, all, GEODETIC MEASUREMENTS & the corresponding MAPPING here in the Philippines were also subsequently done to establish a GEODETIC LINKAGE BETWEEN PHILIPPINES AND JAPAN, to orient Philippines space to the same spatial matrix as the Japanese homeland, and thus into alignment with Japan’s own cartographic conventions. 
 
---Thus, In this hobby of ours EAST pointings should always be watched out.

[Ben Valmores]

As was standard practice, the lion’s share of the surveyors’ earliest efforts were devoted to two things: reconnaissance surveys and the construction of the baselines for the triangulation survey

Essentially imaginary lines of measurement strung across a series of elevated points, these baselines formed the spine (or “primary system”) of the survey to which all other measurements would refer.

The construction of a baseline was no easy task. Climbing a peak and establishing an unimpeded line of sight (which sometimes meant felling trees that stood in the way) demanded tremendous patience and physical strength.
 
Particularly painstaking was the erection of observation stations, some of which were massive in scale, on hilltops and mountain peaks so that surveyors could measure, using a theodolite, the distance from signal station to signal station, a string of which would form a baseline (see image below).

[Ben Valmores]

(This is in Korea)

The baselines constructed by Japanese surveyors ranged from two thousand to forty-six-hundred meters in length, and were constructed in most cases along the spine of Korea’s many mountain ranges.
 
Initially, surveyors divided the peninsula into fifteen triangulation nets: subdivisions of the peninsula, determined by its natural topography, that parceled out the triangulation process into smaller, locally contained units, all of which would eventually be aligned once enough data was collected.

By the end of 1910, the surveyors had successfully constructed six baselines. By March of the following year they had established an “aggregate operative zone” of nearly seven thousand square ri in area and brought the number of baselines up to ten, which then cut through North and South Kyongsang, Ch’ungch’ong, South Cholla, and North and South P’yongan Provinces.

 Taken together, these baselines amounted to 11,327 meters in length (GGK 1914, 21). By 1913, primary surveys were under way in every province in Korea, and by some official estimates the primary triangulation survey would be completed by 1914 (GGK 1915, 10).

[Ben Valmores]

So this is it, TRIANGULATION NETS


parceled out triangulation process into smaller, locally contained units

[Ben Valmores]

Hey Janner & T Hunter, can we now trace how to begin creating a JAPANESE TREASURE MAP? based on Triangulation?

I believe so....

From one triangulation net, it can be....or  from two nets or perhaps, combinations?...yeah really, it can be....

Let us see, lets combine and this image now pops up!!!

A visualization of a typical combined triangulation nets in one possible area, also a possible hiding place of one elusive treasure trover.

Note the multiple scales and systems of measurements.

[Ben Valmores]

It goes without saying that the process described above was heavy on computation.

Indeed, whatever the sophistication of the tools and techniques employed by the surveyors, their maps were only as good as the trigonometric computations made by the mapmaker, which were nothing if not voluminous.

The principal challenge lay in translating data points into a map projection.

okay it's our call now, imagine yourself as the Imperial Japanese Officer Treasure Burial Planner,
Let's put ourselves on their shoes, let's try to have same mindsets and frequency of thinking....

We now have baselines.......

Starting point of understanding....

[Ben Valmores]

 
NEXT,

To put it in context; Let's talk about Survey lines as "treasure grids"/ "Treasure signs"