by Tatiana ILYUSHINA, Cand. Sc. (Technol.), Moscow State University of Geodesy and Cartography
Long before the Christian era savants of Phoenicia and ancient Egypt, and then of Greece and Rome studied and mapped terrestrial surface. Further progress of humanity - what with humming industries and farming, exploration of new territories and the growth of national states-made such work ever more imperative.
Let us take gardening or agri- and viticulture to begin with. Cultivated tracts of land had to be either irrigated or else drained. Such lands were surveyed and marked with a number of reference points for benchmarks. In time these benchmark data were evaluated and brought together for making plans of large territories and whole countries. The very first land-surveying and topographic maps were thus drawn up.
Our ancestors used rather primitive, rule-of-thumb methods in determining geographical latitudes and longitudes, and that did not make it possible to pinpoint the exact position of real objects. But people sought to achieve better accuracy through new surveying methods and instruments. Specific sciences appeared, too. One was topography (topographic mapping) - the detailed description or drawing of the features of an area, district, or locality. Special topographical techniques were developed. As a science, topography remained rather primitive until the 19th century and the invention of modern surveying instruments, making accurate plane and profile measurements possible.
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The scale is an important part of topography. This is the proportion that a plan, map, or model has to what it represents. Maps were drawn accordingly. Say, a military-topographic map that came out in 1846 was scaled 1 inch to 3 versts (1/126,000)*; it had many reruns subsequently and came to be known as the "three-verst" map.
The first half of the 18th century was marked by grandiose geographic discoveries and vigorous cartographic activities**. On Peter I's orders land-surveying works were begun on mapping Russia's inland territories with the aim of drawing a general map. A separate sheet of the proposed atlas was assigned to each administrative locality, and so the scale was chosen accordingly. The latitude of each key town and of territorial boundaries was determined with the use of a quadrant (an instrument for measuring the altitude or angular distance of an object), while the intervening spaces were surveyed visually and through interviews of local residents. In 1810 to 1820 this work took in 200 uyezds (lowest administrative divisions) out of 285 then in existence.
In 1765 the reigning empress Catherine II ordered a master (general) land-surveying plan for the purpose of delimiting land boundaries (relative to state-owned and private estates) to put an end to pervasive litigation. Each landed estate was drawn on a scale of 1 (inch): 100 sazhens (fathoms)***; the scale for urban lands was either 1:50 or 1:100. Overall, as much as 55 percent of European Russia's area was surveyed.
Surveying one particular land plot, one began with measuring its outside boundaries, the contour. If it was formed by straight lines (roads, plowland borders, etc.) alone, it was enough to find a small number of reference points within the locality, put them on paper and connect. But the accuracy of sketching a curvilinear object depended solely on a surveyor's skills, on his ability to represent the object given a minimum of reference points and with as few errors as possible. Things were even more difficult if relief features had to be sketched: besides the two coordinates in a horizontal plane, elevation had to be determined as well.
In old days topographers employed rather primitive tools and techniques, such as hempen ropes and even steps (paces), and then special chains, tapes and ribbons. In the Bible the prophet Ezekiel speaks of "a measuring reed of six cubits long and a hand broad" (Ezekiel, 40 - 43); and St. John mentions "a golden reed to measure the city, and the gates thereof, and the wall thereof (The Revelations of St. John the Divine, 21).
The oldest linear unit was a step, passus. Naturally its length differed with different people. Knowing the average length of his step, a surveyor counted it in pairs (say, steps of his right foot). In ancient Rome two steps, the passus, were equal to what is now 1.5 meters. Thereupon, taking a special table, he translated his data into Russian fathoms (sazhens) and checked them with the milestones (verst posts) set up on the nearest highway.
Then came a surveyor's poll chain used for general land surveying, or chorometry. It comprised 70 links of steel supplied with brass number plates in every seven (to indicate a sazhen). Each plate had figures on. Now and then there occurred chains of 100 links, each link equal to 0.1 sazhens. The chain became a reliable instrument if
* The Russian verst was equal to 1.06 km, or 3,500 English feet; the Russian inch - 2.54 cm, or equal to the English inch. - Ed.
** See: V. Glushkov, "The Ancestrv of Russian Cartography", Science in Russia, No. 5, 2003. - Ed.
*** The sazhen (Russian fathom) was equal to 2.1336 meters, or over 6 feet. - Ed.
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handled by an expert land surveyor: the error for a smooth lowland did not exceed 0.001 of the measured line, and it was not above 0.005 for bumpy and boggy wasteland. A plot was broken into triangles or parallel rectangles. The first, triangular mode provided for staking the plot at key points (from the middle out) and connecting the stakes with lines forming almost right-angled triangles. The other, more accurate rectangular technique amounted to copying a locality's relief. Both were time-consuming and good only for open and accessible tracts, though occasionally used on smaller patches, too.
The steel tape had certain advantages over the chain - it was lighter and handier, and did not sag when stretched over pits and ditches; it produced better results (with the error margin not above 0.0005). But the tape was inferior in strength - if broken, it could not be repaired on the spot by improvised means.
For shorter distances a special sackcloth band, 10 sazhens long, was employed. Divided into sazhens, feet, inches and smaller units, it was placed into a leathern case supplied with a revolving pivot (like a measuring reel). It was handier than the measuring tape and not at all inferior in accuracy. But since it stretched out and broke all too often, such a reel was no good at all for open localities.
There were also mechanisms for determining long distances, too. In the 16th century Jean Fernel, a French mathematician, astronomer and court physician, invented a counter to find the distance between Paris and Amiens.
Put on a horse's saddle, it registered the animal's steps and marked their number by bell jingles. (Incidentally, such contraptions were in use at Alexandria, the Egyptian center of Hellenistic culture, as far back as 1500 years ago.) Pedometers, the devices looking like a regular pocket watch, did the same job. Unfortunately, they broke often and a land surveyor could hardly fix them up.
Odometers, or devices for measuring the distances traveled by a vehicle (by counting the number of turns of the wheels - from 1 to 100,000), proved better in terms of accuracy. The odometer was invented by Leonardo da Vinci (1452 - 1519)*. Such gadgets were of two kinds here in Russia. The first one was in the form of a regular wheel with an assigned length of the rim (usually one sazhen long). Its lever got the counter to rotate. The counter was fitted with a dial having two hands, or needles: one moving a point forward upon every turn of the wheel, and the other actuated after the first had come full circle. The readings of both indicated a distance in sazhens or their fractions.
The other kind of odometers rotated together with the wheels of a coach and counted the number of wheel turns. The verst counter was a modification of this contraption for counting the Russian versts (each, as we remember, equal to 3,500 English feet or 1.06 km); it was mounted within an iron box having two compartments (one for the pendu-
* See: K. Frolov, "A Genius of Renaissance", Science in Russia, No. 6, 2003. - Ed.
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lum and fixings, the other - for the dial plate, which showed the number of rotations from 1 to 10,000). This box was fixed to the right hind wheel of a coach. One copy has survived to this day, it is among the collection of the Museum of Moscow State University of Geodesy and Cartography*.
One essential drawback of such devices, which were capable of measuring big distances, was that the wheel followed the rough terrain features, and therefore the readings showed the total length of the way covered by the carriage, with all the ruts, grooves, pits and holes and detours, too, rather than the direct, straight distance in a crow line.
Box compasses were a handy tool as protractors. These devices have a curious history. Even aeons ago people knew that "magnetic" ore attracted iron. As far back as 2,700 years ago Chinese travelers carried instruments predicated on this natural phenomenon: a small vessel filled with water had a floating magnet band made into wood in the shape a human figurine, its forefinger pointing south. The Arabs were the first to get wind of this wonder gadget.
In the Middle Ages Italian seamen replaced the floating magnet by a fixed needle enclosed into a small case of box-tree wood (buxus in Latin), and they named the new instrument bussola, that is made of bussolo (or bossolo), meaning the same material, box-tree. Thereupon they placed a "wind rose" on the bottom-this way a mariner's compass (compasso) was born. But unlike its predecessor, the compasso had no sighting device (dioptrics), or plate with slits. Both types of protractors had at first been used by mariners only until Niccolo Tartaglia, an Italian mathematician and land surveyor (ca. 1499 - 1557), found they were good on land, too.
Small bussolas, 5 to 10 cm (2 to 4 inches) across, were adopted for land surveying. They were of two kinds - either mounted on tripods (or pales) or portable. The tripod-mounted bussola included an outward limb**, alidade (index bar), two sights and a glassed - in flat cylindrical box containing a similar limb and a magnetic needle. The portable bussola was a box compass (its needle had a light limb of board or aluminum pasted on) supplied with dioptrics (sights).
An astrolabe was found to be a better instrument for place and profile measurements. At any rate this instrument was used in general, all-out land surveys. It comprised a graduated limb of silver-plated brass, an alidade (smaller than the limb's diameter), and a bussola, sights, and a stand or tripod. Right-angle mirrors were often employed as well-instruments known still in ancient Egypt for marking terrestrial surface with straight lines crossing at 45°, 90° and 135°.
* See: T. Ilyushina, "History of Cartography of the Asian Part of Russia", Science in Russia, No. 4, 2006. - Ed.
** Limb - here a flat ring with a scale marked on its lateral surface and dividing the circumference into equal parts (degrees, their fractions, etc.); it was employed as a protractor. - Ed.
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Plane-table surveying was on optimal method both in field and on paper. Readily adopted by geographers and the military, it was also known as a mensula technique, la mensula meaning a "small table", or board, thought to be invented by Professor Pretorio of Nuremberg (1537 - 1616). It was a plane-table board with paper pasted on it that made it possible, with the aid of an alidade cum dioptrics (sights), to determine angles between horizontal projections of lines.
Exploratory, or eye surveying, was done as follows. Choosing some reference point (say, on a road), a land surveyor took a box compass and observed its azimuth. Then he marked off a corresponding direction with a protractor on a sheet of ruled paper fastened to a plotting board. Carrying forward the azimuth, he sketched the relief of a locality (mountain ridges, eminences, saddles, cols, slopes and the like) on either side of the highway. Although a rough, not elegant technique, it saved time and allowed to obtain a fairly reliable plan. Important, benchmark objects were penciled with crayon, and those of secondary significance, just indicated by a few dashes. Relief features were represented by isohypses* and hachures (hatched), with the hatched parts accentuating conspicuous and high-visibility landmarks. The meridianal direction and scale were dotted.
An adequate set of vivid symbols and legends made map interpretation much easier. The scale depended on the mapping deadline (the shorter the time, the smaller the scale). As a rule, the scale was 1 inch per 200 sazhens or per 1 verst or per 2 versts.
Compiled on the basis of the General Land-Surveying Plan was the Atlas of the Kaluga Gouvernement (Kaluga province) that came out in 1782. The atlas comprised a general map of the gubernia as well as detailed maps of constituent uyezds (districts) and towns. In keeping with the Senate's ukase, the following year work began on such atlases for each gubernia (administrative province) where land surveying had been completed. Afterwards such atlases were used by the government for making the first detailed map of "hundred sheets" for Russia's European part.
Meanwhile the St. Petersburg Academy of Sciences supplemented the above atlas with a fundamental economic and geographical work, the Topographic Description of the Kaluga Gouvernement (1785). It furnished data on local navigable rivers, land cultivation, industries, handicrafts, soils, forests, factories and so forth. It also described ancient burial mounds and whatever "remarkable there could be concerning local history and geography".
In 1849 the surveys of the 18th-century General Land-surveying Plan were revised and substantiated mathematically, in the form of astronomical points. This work was done under the guidance of A. I. Mende, an expert land surveyor, and with the assistance of the Russian Geographical Society.
Private enterprises turned to cartography and map making from the early 19th century on, and there appeared general and special-purpose plans and drawings made for governmental and other bodies. Topographic maps drawn in the latter half of the 19th century were of larger scale and higher accuracy.
In our days topography has been revolutionized with the progress of the earth sciences and space technology.
* Isohypses (hypsographical curves, contour lines) - lines on a map connecting points on terrestrial surface with identical absolute altitude and representing relief features. - Ed.
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