After all, where is the Center of Portugal? The math answer: it depends
Vila de Rei, in the district of Castelo Branco, has been proud for two hundred years to have in the county the reference that confirms that it is the Geodesic Center of Portugal. However, it is in the municipality of Mação, in the district of Santarém, that the Geometric Center is located. What is the “true” Center of Portugal, then? The controversy has been raging for more than a decade when Professor João Filipe Queiró, from the University of Coimbra, revealed his years. The mathematician was in Abrantes to explain them, in a lecture by the Tubucian Academy.
It was the mathematician and astronomer Francisco António Ciera who first defined, in 1802, where the Center of Portugal was located. Maria I to analyze the country and prepare the “Geographic Chart of the Kingdom”, and the configuration of Picoto da Melriça in Vila de Rei.
Two hundred years later, the mathematician, in agreement with João Filipe Queiró, added other accounts to those of Ciera, namely whether to know whether with the Geometric and Geographical Center.
To understand the differences, it should be noted that the Geodesic Center refers to a point found in a coordinate system, while the Geographical Center refers to the center of a figure figure. It is in Vila de Rei that is marked in the national cartography 0.0, it is from the point that all measurements or coordinates are made, in latitude and longitude. And it is at such a high point that from there it seems that the entire country can be seen.
But the Geographic Center will be 11 kilometers away, in the county and in the district in another; in Mação, in a triangulation of vertices between the localities of Amêndoa and Arganil, and in a background, according to João Filipe Queiró. For this mathematician, despite the small margin of error, the Center of Portugal is not in Picoto da Melriça, in Vila de Rei, but in the neighboring municipality.
“Pico da Melriça was not chosen by chance. It is a very high point, in an area that is clearly central, with great visibility. It is the point chosen to be the center of the primordial geodesic network of Portugal and well chosen!”, considering the full professor, who classifies as “extraordinary” the fact that the Geodesic Center is close to the Geodesic Center.
During a lecture organized by Academia Tubuciana de Abrantes, on March 24, the professor of the Mathematics department at the University of Coimbra says that he decided to focus on central Portugal after a visit to Cabo da Roca, where he came across the sale of “diplomas”, attesting that their holders had been at the westernmost point of the Eurasian mass.
“There, when I was in line, my certificate of westernity occurred – a matter of looking for other specific points that have been looking for me for many years of interest exclusively for reasons. Remind me of an obvious candidate: central Portugal”, explained.
He noted, however, that the municipality of Vila de Rei already claimed to have the center of Portugal in its territory, a summit with a viewpoint. The professor of this location a map, published by the Geographical Institute of 1983, where he saw the legend ‘Primary geodesic network’: The central node network, is visible in the middle of the map of Melriça, in the municipality of Vila de Rei. It is an elevation of a geodesic landmark with 593 meters of altitude, on top of which stands an imposing geodesic landmark.
Aware of the existence of the Geo Center, João Filipe What a title of curiosity would you find, then, to study mathematically the point where the Geometric of the country A task that is only easy to present as, done as accounts, not controversial.
But we explain the beginning of the calculation process: in the first place, “the question of what to understand by ‘centre’ an irregular figure, without symmetries. The center of a circle, of an all, of a rhombus, we know what it is. But how to know what is the center of a figure like the map of Portugal?”, that is, “in a country it is more complicated”.
It states that the starting point must be the definition of the center of a plane figure. The principle of Archimedes and its lever were used, the so-called “principle of Archimedes equilibrium”, taking a figure from mainland Portugal that the system is in a single equilibrium, this point is the center of gravity”, he explains.
And as triangles are of great importance in this story, the mathematician started by triulating a polygon, to calculate the polygon center later, to divide the map of the country in absolute terms – but being any triangles, a parallel calculation led to the same – each time concluding smaller ones, “then using the integral calculus formula and falling into double integrals that you see using Green’s theorem”, explained.
In his papers, he ignored the sphericity of the Earth because “Portugal is so small that the sphericity of the Earth has an effect that you can neglect”, he said. That is, before applying as formulas to determine the center of Portugal, it was observed that, as the country is very small in relation to the perimeters of the Earth, “there is no sensible error in disregarding the sphericity of the globe and considering the territory flat”.
Mathematical mathematics later, João Filipe Queiró concluded, with a margin of error that seems to him “small”, that the Geometric Center of Portugal does not find an end at the peak of Melriça, near Vila de Rei, but a little more the southeast formula.
“The result is that we arrived at a point about 11 kilometers east and 3 kilometers south of Pico da Melriça, which we can call the Geometric or Geographical Center of Portugal” between the towns of Amêndoa and Arganil, in the municipality of Mação, he said. .
Several years have passed since the first time the mathematician presented the study, he continues to question himself about the “interest”, even if it can be used for some tourist purpose. The example of other countries suggests not. “The city of Lebanon, Kansas, in the United States, didn’t take much advantage of the fact that it is located in the geographic center of the country”, he recalled.
However, Jorge Teixeira Pinto, from the Portuguese Geographical Institute (IGP), responsible for a similar study, that no one can definitively state where he specifies the Center of Portugal due to the specifics of the central point to determine the central point.
“For the inauguration of the Geo Museum – installed in Picoto da Melriça by a municipality of Vila de Rei and the IGPdé protocol – the question of knowing the knowledge of the Geometric Center of Portugal”, recalled the official to the Lusa agency. According to Teixeira Pinto, “scale dependents that are done and impossible are done at a scale of 1:1”.
Thus, and with a legal determination of the central point of the country, it is Vila de Rei, as the Geodesic Center of Portugal, which continues to receive thousands of visitors every year.
Professor Vitor Lobo, presents partners from Academia Tubuciana in the lecture, that the municipalities can collaborate and be, both win-win tourism, that is, “somehow in Melriça, to say that: that it is the closest geodesic landmark to the geographical center of Portugal; and in the other place an obelisk is placed indicating that that is the Centro Geometric Portugal”.
And where is the country’s demographic center of gravity?
After carrying out the work on the Geographical Center, João Filipe Queiró came up with the notion of possible work in the Center of Portugal: what could be called “the demographic center of gravity” of the country. “The rigorously serious definition of the system of points constituted by all the inhabitants of the territory, each one in its position (and all with the same mass, which makes it purely geometric)”, he explains.
How to calculate such a point at any given time would be impracticable, as it would simplify the problem by considering the 278 municipalities on the continent and, for each of them, assuming the respective population concentrated in the county seat.
He stressed that, unlike the geographic center, the demographic center of Portugal is not fixed, because the distribution of the population in the territory changes over time, as the Census results have shown.
“The formulas they use were the same, that is, for a finite set of points with masses. The points are the seats of the municipalities, whose geographic coordinates were necessary to register. The masses are the populations of the municipalities, determined by official censuses”, he said.
The mathematician calculated the demographic center for the fourteen censuses carried out in Portugal since the 19th century, in the years 1864, 1878, 1890, 1900, 1911, 1920, 1930, 1940, 1950, 1960, 1970, 1981, 1991 and 2001. number of councils since 1864 has remained stable, which facilitates the teacher’s work.
Among the new municipalities, only Entroncamento (which appears for the first time in the 1930 census), Amadora and Vendas Novas (1970), and Odivelas, Trofa and Vizela (2001).
According to João Filipe Queiró, the demographic center of Portugal was, in 1864, near S. Miguel de Poiares, about 17 kilometers east of Coimbra. Then it moved slowly to the south and a little to the west, until 1930, it passed into that westward movement.
“The most advertised was 1960, and in that decade it is explained between the decade of the media, namely the interior, namely the interior.
In 201, the demographic center was located about 30 kilometers southwest of Coimbra, on the border between the municipalities of Soure and Pombal.
Consider that “at first glance, this location in the demographic center of Portugal may surprise us” and you will be right. However, this location is explained by the fact that the population of mainland Portugal is very close to the coastline between Setúbal and Braga.
It will now be interesting to see where it stands in 2021, the year of the last population census. The professor supports that the demographic center does not move much in relation to the 2001 position, despite the large concentration of people in the Lisbon metropolitan area. “It is difficult to move further west and, on the other hand, the Greater Porto region is very populous, so there should not be a large displacement of the demographic center to the south.”
His background is legal, but luckily, journalism fell into his lap more than 20 years ago and has never let go. It’s normal to be against it, maybe that’s also why it has a path taken in reverse: initiation in the national, who knows, finishing in the regional. TSF radio became the beginning of Diário de Notícias, one later bet on Macau’s economy as a bridge from Portugal to China. After a lifetime in the capital, he returned to Abrantes in 2015. He likes to live in the countryside, he wants the quality of rural life for his daughter and, if possible, dedicates himself to telling stories.