Rank Size

La apertura de la economia chilena al sistema mundial desde mediados de 1970 ha modificado el marco general de las interacciones urbanas y, en consecuencia, ha impulsado cambios de cierta magnitud en el modelo de organizacion del sistema urbano. U na de las transformaciones mas importantes concierne a la reduccion del desequilibrio en la distribucion de los asentamientos por tamanos (de poblacion, economicos…), debida al crecimiento de los nucleos intermedios, en especial de aquellos asociados a bases economicas locales cuya produccion se ha incorporado al mercado mundial. En este contexto, la presente investigacion tiene por objetivos mostrar cual ha sido la influencia en el sistema urbano nacional de la fuerte conexion de la economia chilena a la economia mundial, y valorar los cambios recientes de la jerarquia de los centros urbanos, que tiende al declive de la primacia urbana. El enfoque metodologico se fundamenta en el reconocimiento de la «ciudad» como unidad economica y funci...

1- INTRODUCTION
In the urban economics literature - which does not have much history in Iran - it has been shown that the performance of cities depends on their structure. In other words, there is a significant relationship between the performance of the city and its structure. Accordingly, despite such a relationship, the future performance of cities can be predicted based on their structural changes. Therefore, this study is designed to investigate the trend of structural changes in Iranian cities as well as the regional differences of the urban system and based on the first urban position.

2- THEORETICAL FRAMEWORK
Although there have been many studies examining primary urban indicators in each region, based on the research conducted in this study, a study examining primary urban indicators by city in all provinces of Iran for the period leading up to the 2016 census, have not been observed. This makes this study different from other studies in this field. Thus, this paper is innovative in comparison to previous studies in two respects. First, it used the nine primate city indicators individually to realize the primary cities of all cities in the country, as well as all cities in each province in the country, and compared them among them. In addition, the rank-size rule has been used to measure the balance or imbalance in population distribution. However, in previous studies, primary cities have been calculated only for cities across the country or in specific regions, and only a few of these indicators have been used, with no comparison between them. Second, the survey period in this study covers the year 2016, based on the most recent information available in the field. However, primate city surveys of cities across the country (to the knowledge of the researchers in this study) have not been conducted until the last census period.

3- METHODOLOGY
This study is designed to investigate the trend of structural changes in Iranian cities as well as the regional differences of the urban system and based on the first urban position. To achieve this goal, this paper have been used nine Primate City indexes Including primate city Index, Two City Index, Ginsberg Index, Mehta's Four City Index, Moomaw & Alwosabi Index, Herfindahl Concentration Index, Herfindahl Deconcentration Index, Entropy Index and Mousavi urban domination. The data of this study are extracted from the census in Iran of 1976 to 2016.

4- RESULTS & DISCUSSION
The results show that the primate city phenomenon in the urban system of Iran has existed throughout this period. Also, the primate city indicators in these years show the move towards more balance in the urban system of the country. However, the primate city rate has decreased during the studied years and the decreasing trend in the studied indicators is consistent with each other. However, according to the available evidence, the results show the creation of prime cities in the Iranian urban system instead of a prime city. Also, based on the results of this study, the majority of the studied indicators up to 2006 show that the highest and lowest urban prime rates were in Tehran and Mazandaran provinces. Qom province has the highest urban prime in the urban system of Iran since 2006. Accordingly, it can be expected that the change in the structure of Iran's urban system will provide the way for future functional changes in them.
5- CONCLUSIONS & SUGGESTIONS
The status of primate cities in different regions is influenced by situational characteristics and urban location. The study of regional primate cities during the study period, using Mehta's Four City Index, showed that border regions and regions close to border points have shifted from a predominant primate city status to a desirable or minimal status. This is because the flow of domestic goods and services moves from larger centers to smaller centers, and as this flow passes through different regions to reach the center, its impact is felt in intermediate regions, causing the primate city phenomenon in some domestic states (especially those close to other regions from the center of domestic goods and services).

The current study analyzing the urban system of province Hamadan during 1335-1390; in this research use from prime urban methods, rank-size, entropy, Lorenz curve and Gina coefficient; The research method in this study is quantitative-analytical and the tools of collecting of documenting information, library and scoping. To do the calculating and analyzing the information used from Excel, SPSS, and GIS software. The result of searching are show that the prime urban index in the studying period was in the urban system of province Hamadan and it ۥs process was additive. The entropy coefficient during 1335_1385 has been towards a more balanced distribution of the number of cities in the urban system. According to the Lorenz curve , administering the aggregation percentage of number and the population of cities of province Hamadan during 1335_1390 had more distance from the normal line and despite the increasing the number of cities in the province , the Gini coefficient didn’t tۥ have ...

La apertura de la economia chilena al sistema mundial desde mediados de 1970 ha modificado el marco general de las interacciones urbanas y, en consecuencia, ha impulsado cambios de cierta magnitud en el modelo de organizacion del sistema urbano. U na de las transformaciones mas importantes concierne a la reduccion del desequilibrio en la distribucion de los asentamientos por tamanos (de poblacion, economicos…), debida al crecimiento de los nucleos intermedios, en especial de aquellos asociados a bases economicas locales cuya produccion se ha incorporado al mercado mundial. En este contexto, la presente investigacion tiene por objetivos mostrar cual ha sido la influencia en el sistema urbano nacional de la fuerte conexion de la economia chilena a la economia mundial, y valorar los cambios recientes de la jerarquia de los centros urbanos, que tiende al declive de la primacia urbana. El enfoque metodologico se fundamenta en el reconocimiento de la «ciudad» como unidad economica y funci...

This study assumes areas between the Central Zagros region and Central plateau of to play an important role in the shaping social and economic complexity and the formation of urban infrastructure during the late chalcolithic period of the region. Regarding the issue an archaeological survey conducted in the area, 39 sites were identified and were archaeologically analyzed. For spatial data analysis both Rank-size and Entropy analysis index were used. The Rank-size data and their distributional pattern across the area indicated a close relationship between the site size and the settlements functionalities as well as their expansion on the plain and their communications with the adjacent regions. The concave logarithmic graph of Rank-size analysis and increasing Entropy index yielded from the settlement size measurements, resulted in the lack of existence of a concentrative organizational system of production or a high level communicating network for the settlements of the Hamadan Plain during the late chalcolithic period. Thus the result of this analysis indicates the fact that the cultural complexity or production systems of the Late Chalcolithic occupants of the area did not follow the central place or other centralized system of relationships as may have been seen from the other late Chalcolithic sites of Iran.

In Archaeological Studies of the Fertile Crescent, the Central Zagros region is very important, due to its special geographical and geomorphological features, mountains and plains between the mountains and creates the appropriate environment for the formation of the settlement in various eras. The most important indicators of cultural changes in the Chalcolithic period are human-environment interaction, population growth, expansion of cultural exchanges, more specialized jobs, technology development Tooling, familiarity with the metals and metallurgy, focus on rural and food production. The needed information research is obtained through the archaeological survey; statistic data of the research are obtained of five regions of Asadabad, Skinheads, Kangavar, Sahneh and Harsin. Here, by survey the 152 Chalcolithic sites in the region, we are trying to investigate the settlements and population increase phenomenon on the basis of newly discovered evidences; as there is increasing number of settlements during the early to late Chalcolithic period. Overall, the analysis shows that most of data is about the sites related to late Chalcolithic period and Maximum area and average altitude in the whole areas as well and the next group with largest number and area is sites attributed to Middle Chalcolithic. This evidence suggests that during the early to Late Chalcolithic period settlements needed more lands to settle, so they move to the highlands. But it also requires appropriate conditions for living in highlands as these areas have all the necessary parameters for population growth; this conditions to increase the extent of the settlements and population would provide by rising trend of altitude and also sites close to rivers during the early to late Chalcolithic and it seems that in this region over-population is a widespread phenomenon. As the matter of fact, 89/57 percent of surveyed sites are located at an altitude of 1500 to 1800 meters above sea level (a.s.l) on the hilly area of piedmonts. This area is drained by several branches of the river; due to the relatively high slope areas has high-dens networks, both seasonal and casual. The sediments of surrounding mountains are heavey-densed due to the influence of seasonal networks around the slopes which resulted expanding the settlements and farms to down-stream slopes. In addition, about 62/5% of sites have located at a distance of less than 1000 meters from seasonal streams and networks. One of the common perceptions of people concentrations along the rivers would be mobility and nomadism; since the water supply needed temporarily for living along the rivers. Due to the high risk of being sedentary along the rivers, the sites must be locating in such condition which is away from the risk of flooding. Some evidence suggests that the nomadism started during chalcolithic period in Central Zagros for the first time. It certainly has been related to increasing settlements during the given period due to increasing of mobility or populations, changing conditions and looking for suitable places. On the other hand an increasing of chalcolithic settlements in the region, leading to different subsistence systems responding the population requirements. Looking at the data of this research about Kangavar valley (eastern Central Zagros) is evident that in the number of settlements there has been growth from the West to the East of the region during early to Late Chalcolithic period and this is probably due to the high pressure of population growth have moved towards western areas.

According to the classical Zipf-distribution, the second largest city in a country or region would have one half of the population of the largest city, the third largest city one third of the population of the largest city, et cetera. This can be expressed with the formula:

P(r) = P(l)/rZ 

where P(r) is the population of the city of the r-ranked city within the totality of the sample, P(l) the population of the largest city, r the rank of the city (1, 2, 3, …) and Z is a constant in the order of magnitude of 1.  This rank-size rule has been empirically studied in many regions throughout the globe for various time periods; many cases satisfy Zipf’s law very closely with values for Z around 1, whereas in other cases rank-size distributions of populations of cities obey power-law behaviour, but have a different power exponent Z  - for our English example here, Z = 0.706, for instance, indicating a more "equal" distribution of population than in the classic Zipf-model. 
The working of the process which generates these patterns is still under discussion; but most probably they result from the complex interactions within the network of settlements and their hinterland which produce an uneven distribution of demographic and economic potential and a hierarchy of cities. 
For more on these phenomena, see also: http://www.academia.edu/512028/_Johannes_Preiser-Kapeller_-_Ekaterini_Mitsiou_Hierarchies_and_fractals_Ecclesiastical_revenues_as_indicator_for_the_distribution_of_relative_demographic_potential_within_the_cities_and_regions_of_the_Late_Byzantine_Empire_in_the_early_14th_century