«4TH INTERNATIONAL CONFERENCE RECENT PROBLEMS IN GEODESY AND RELATED FIELDS WITH INTERNATIONAL IMPORTANCE February 28 - March 2, 2007, Inter Expo ...»
4TH INTERNATIONAL CONFERENCE
RECENT PROBLEMS IN GEODESY AND RELATED FIELDS WITH
February 28 - March 2, 2007, Inter Expo Centre, Sofia, Bulgaria
GEODETIC, ASTRONOMIC AND CARTOGRAPHIC
LANDMARK – “24 MERIDIAN, 42 PARALLEL”
NEAR THE CITY OF VELINGRAD“The enormous natural wealth of the West Rhodopes is reason large part of the mountain to form the biggest “Ecological brick” of the European continent”. 
GEORGI PUHALEV, VENETA KOTSEVA,ASSYA MILEVA (BG) ABSTRACT.
The ideas of the so-called Velingrad’s meridian and its materialization on the terrain in the conditions of newly-projected forest park like a tourist attraction have been presented. This unique geodetic, astronomic and cartographic landmark near the city of Velingrad - the point with 24o East longitude and 42o North latitude, that is situated in the new forest park in the close proximity of the State Game Stock-breeding farm “Alabak”, has been described. The history of the international acceptance of the Greenwich meridian in its quality of initial zero-meridian has been elucidated.
The anteka, antipode and perieka of the Velingrad’s point have been determined. The localization of both Velingrad’s meridian and intersection point 24oE and 42oN by GPS receiver and the projected special geographic ground around it have been described.
This work presents the idea, elaboration and the geodetic grounds of a project about new Bulgarian forest park. Now it is named in Bulgarian 24oE, 42oN. The latter means it is situated in vicinities of a point with following geographic coordinates + 42o North latitude and + 24o East longitude. The idea of the so-called Velingrad’s meridian and its materialization on the terrain in the conditions of newly-projected forest park like a tourist attraction has been given in 2000 by the well-known citizen of town of Velingrad and socially active person, professor on organization and planning of activities of the landscape architecture from the University of Forestry, Dr. of Technical Sciences Georgi Puhalev in .
In 2001 a project named “Integration of efforts to information exchange and regional cooperation about landscape planning to be mark the intersection point with geographic coordinates + 42oN and + 24oE in the region of the town of Velingrad” has been elaborated . This project brings together participants from Tourist Society “Yundola”, Information Center for small and middle business in Velingrad, Foundation “Eco-community”, Tourist Society ”Ostrets” and University of Forestry in Sofia. The purposes and tasks of the elaborated project resulted from the lack of information about the local landmarks and attractive tourist routes. And the last ones call for their clear marking on the terrain and presenting the interesting knowledge and services by the tourist societies to the tourists who visit the Velingrad Municipality. All this requires the elaboration a clear strategy and the integrated efforts of all the parties concerned . The new geographic landmark, the marking of the convenient route to it and the designation of the intersection point, of the meridian and the parallel towards it will popularize this unique point after the completion of the new park and the tourist route leading to it.
The first project of this forest park was elaborated in the diploma work by the young landscape architect Assya Mileva  from the University of Forestry, whereas the geodetic, cartographic and consultancy foundations of the project were laid down by Ph.D. Veneta Kotseva – Assoc. Prof. in General, Higher and Applied Geodesy. The activities under the project included at the first place the elaboration of a geodetic basis in scale 1: 1 000 on a terrain of approximately 10 decares around the point 24oE, 42oN. This was followed by the extraction of the necessary taxation indicators from the forestry organization plan of the area with regard to the sections and subsections of the forest in the vicinity of the point 24oE, 42oN – size of the surfaces, vegetation species, soils, estimates, age of the plantations etc. The purpose is to obtain a full bio-geographical picture of the object. At the third
place, the cadastral elements in the scale of the forest map was looked for, i.e. in the scale of 1:1
000 and longitudinal sections were elaborated in different geographic directions in order to ensure the visual connection of the object with the quarters of Velingrad on the basis of its current urbanistic plan.
2. Geodetic, astronomic and geographic landmark.
The forest park “24oE, 42oN” is situated above the natural landmark “Kleptuza” near Velingrad. It is interesting that namely in this territory a symbolic astronomic, geodetic and cartographic landmark exists – the intersection point of the +42 parallel (+42°N) and +24 meridian (+24°E). The forest park was intended to serve both for short-term leisure and long-term leisure after the creation of the necessary material basis in the forest park. Its construction aims at attracting more visitors and tourists in Velingrad by offering to them a new tourist and geographical attraction. The discovery and determination of this unique point on the territory of Bulgaria (φ = +42°; λ = +24°) is of particular importance not only for our country, but especially for Velingrad.
Fig.1. Fragment of the map of the Military Topographic Service of Bulgaria with the graticule and nomenclature of the map sheets in the area of the town of Velingrad The point is emblematic also from a numerological point of view because of the coincidence in the numbers of the latitude 42° and the longitude 24° as in a mirror.
3. The intersection point of the +42 parallel and the +24 meridian
Velingrad, UCATTU (Unified Classificatory of Administrative-Territorial and Territorial Units of the Republic of Bulgaria) 10450, is the town of third functional type and the center of the municipality with the same name, which is situated in the District Pazardzhik (PAZ 08) in the South Central region of Bulgaria. It is situated in the West Rhodopes, 49 km from Pazardjik and it has approximately 26 000 inhabitants. It is declared national spa- and climatic resort. Wood-, woodprocessing and machine-producing industries are developed; there are 5 forest farms; mainly potatoes and hops are grown and there are many greenhouses. Near the city is situated the Karst source “Kleptuza”, there are 70 more mineral water sources and drillings with water temperature of 91°C and debit of 130-140 liters per second. There are 47 spa-centers and leisure homes in the city.
Velingrad is a beautiful resort place, known for its mineral water sources and pleasant climate.
There are many natural and archeological landmarks near the city. The city has been populated since ancient times. Along with all these advantages, Velingrad could be identified with one more geographical landmark – the intersection’ point of the meridian with the parallel, in particular the +24 meridian. From the point of view of mathematical geodesy and cartography especially important are the meridians, multiple by 6 (six) or 3 (three).We take into account the particular situation of the city, which it has in the so-called “graticule” – the imaginary network of parallels and meridians on the Earth and their projection onto a flat map, applied in determining the degree’s coordinates of every point on the Earth. These points are determined in a unified coordinate system.
The foundations of this framework are the plane of the equator and the plane of the so-called “zero” or prime meridian. Therefore the determination of each point on the surface of the Earth follows the geographical coordinates: longitude and latitude.
Authalic latitude φ of given point P may be defined as the angle formed by a pair of lines extending from the equator to the center of the spherical Earth, and then from the center of our position P. It is measured respectively to the north or to the south of the equator from 0° to +90° and from 0° to ° - respectively north (N) or south (S) latitude , , , when using digital databases and map projection equations. It is normally given in degrees, minutes, and seconds, using the sexagesimal (base 60) number system developed by ancient Babylonian mathematicians.
Authalic longitude λ indicates the situation of the point with relating to the prime meridian and is determined as the angle formed by a line going from the intersection of the prime (Greenwich) meridian and the equator to the center of the spherical Earth, and back to the intersection of the equator and the “local” meridian passing through the position P. Longitude is measured to the east and to the west from 0° to +180° by adding the words “eastern” (E) or “western” (W) or from -180° to +180° for digital databases and map projection computations . The differences in the longitude from the point of view of the time define the time zones in the various parts of the world and the difference between the time zones is equal to 1 hour = 15° because the circle is split not to 360° but to 24 hours. The position of the 180° meridian in the Pacific Ocean opposite the prime meridian provides a convenient place for the International Data Line.
4. History of the zero meridian of the Earth.
It should be noted here that the determination of the points on the surface of the Earth with the help of both latitude and longitude was introduced more than two millennia ago by the famous Ancient Greek philosopher Hiparh of Nikea (born approximately 180-190 BC, dead in 125 BC).
The ancient Greek scientist Eratosthenes (born approximately 276 BC, dead in 194 BC) is known for placing the bases of the mathematical geography and of one of the earliest prime meridians through his home city of Alexandria. Throughout the past historical periods the longitude has been measured from different starting lines. Beginning in the mid-1600s, numerous countries, each with patriotic ambition, published their own maps and charts with the prime meridian running through their capitals. The result obviously was much confusion . Until the discovery of America the longitudes were determined arbitrarily.
The first recognized starting line in the world is from 1493. This is the prime meridian of the westernmost point of the known world, i.e. of the famous Iron Island (Ferro Island, from the Latin “ferrum” – iron) which is one of the Canary Islands.
In 1633 as a prime meridian has been adopted the one crossing Paris. Later in Russia the prime meridian was considered to be the one which crossed one of the hills of the Pulkovo heights, elevation 73 meters, where in 1839 the Pulkovo observatory was built, near St. Petersburg . And in England as a prime meridian was considered the meridian of the Royal Greenwich Astronomic Observatory established in 1675 and situated in one of London suburbs. This meridian has been kept as a prime meridian also nowadays, even though in the 50’ of the 20ty century the Greenwich Observatory was moved 70 km to the South-East from its previous location to the XV century castle Herstmonsew.
The choice of the prime meridian has always been a matter of international importance and national pride. In order to resolve the problem of measuring the time in different points of the Earth it was necessary to introduce a normative determination of prime meridian. Therefore in 1884 in Washington, D.C., during a special International Meridian Conference the Greenwich meridian was universally agreed as prime one , . Now the Greenwich meridian is materialized on the terrain with wide bronze strip and it is a popular tourist attraction where each visitor puts feet on the prime meridian λ = + 0° and takes pictures as a souvenir.
5. The Velingrad point and its anteka, antipode and perieka.
Let’s follow on the map where does the meridian (+24°) cross the world. It goes through Athens, Cania on Crete Island, through Africa where the border between Sudan and Chad is, between Angola, Zaire and Zambia. Following exactly the 24th meridian we reach the so-called “anteka” situated in the Madagascar Plateau in the Indian Ocean. That is the name of the point, which has the same East longitude (+24°E), but its latitude has the opposite algebra sign, i.e. (–42°S). Besides, this point has two more particular points which are analogous, but situated in different parts of the Earth. One is called “antipode” (from the Greek words “anti – opposite, against, and “podos” – foot), which means a place on the Earth which is exactly the opposite of another place. In our case this concerns a point with longitude (-24°W), i.e. (+156°) and latitude (-42°S). It is situated in the Southern hemisphere but diagonally with regard to the Velingrad point. The other point is called “perieka” (from the Greek “periekos” – a citizen of ancient Sparta who did not enjoy full rights) and is with longitude (-24°W), i.e. (+156°) and latitude (+42°N). When on the Velingrad point it is a summer day, in the anteka it is a winter day, in the antipode – winter nights and in the perieka in
the Pacific Ocean a summer night – Fig. 2 :
Fig.2.Velingrad’s point with its anteka, antipode and perieka.
If we try to enter into the mysteries of the geometric substance of the Earth’s ellipsoid surface, we could encounter many more theoretical abstractions, definitions, formulas and calculation methods.
According to the transversal cylindrical projection of the great German mathematician Karl Fridrich Gauss (1777-1855) the Earth’s surface in divided by the meridians to 60 zones called the Gaussian zones, any of which encompasses 6° on the longitude. Fig. 3 shows 3-degree and 6-degree Gaussian coordinate systems . The middle meridian of each zone is called principal (basic) meridian and it divides the zone to two equal parts – eastern and western.