@article { author = {Dadashpoor, Hashem and Mamdoohi, Amir Reza and Afaghpoor, Atousa}, title = {Analysis of Spatial Organization in Urban Network Based on Air Flows of People: Empirical Evidence for Iran}, journal = {Human Geography Research}, volume = {46}, number = {1}, pages = {125-150}, year = {2014}, publisher = {University of Tehran}, issn = {2008-6296}, eissn = {2423-7736}, doi = {10.22059/jhgr.2014.50597}, abstract = {IntroductionStudying the spatial structure of urban systems and the inter-urban relationships in particular,has occupied a special place in the context of urban and regional studies for a long time(Meijers, 2007, 245). Since the late 1960s and the emergence of a system approach an urbansystem is not only a set of physical instances- in this case urban nodes- but rather it includes thespatial interurban linkages (Simmons, 1978) and is defined through relations and flows amongcities and their position in the outer complex network. Therefore, a change in any definingcomponents of an urban system (including nodes and linkages) can be associated with a changein its spatial constellation including spatial structure and organization. In other words, increasein accessibility between places are more a function of cross-border networks and areincreasingly determined by flows within system (Derudder and Witlox, 2005; Neal, 2010) ratherthan what fixed within them (Smith, 2003).As most of empirical evidences have been done so far was based on location attributesderived by size-based approach (like population), a little attention has been paid to connectionsbetween urban nodes. Apart from these short comings, few attempts are made to propose a  methodology for assessment and evaluation of an urban system configuration based on theanalysis of exchanges flows. Therefore, in one hand, this article attempts to present a morecomplete and advanced methodology of the study on the nature of the spatial constellation inurban systems to advance this research field. This helps identification of different dimensions oftheir configuration as derived from an interaction approach. On the other hand, it attempts toidentify urban spatial constellation by providing empirical evidence from Air Passenger Flows(APF) in 2006 and compare this with the resulted urban hierarchy based on population in thesame year.MethodologyIn this study, data were used from long-distance personal travel. With regard to the purpose ofthis research and within its defined theoretical framework, only O-D data were applied. Therequired O-D data for APF were obtained from the statistical year book of Air Transport of Iranpublished by the Iran Airlines Organization (IAO) in 2006. According to this report, there were59 domestic airports in Iran in 2006, with the nearest city to each airport utilized as the relevanttransport network (city) node in the calculations (Statistical Annals of Aerial Transportation ofIran, 2006).The spatial scale of this study is national, but in respect of mentioned limitations inproviding geographical information on the origin and destination of long-distance travels, it ispreferable and plausible to use political division of provinces as delimitation of the study area.For this reason, we employ thirty provincial main urban areas in 2006 as spatial units ofanalysis. As a result, the spatial level has been restricted to inter urban relations through flowsof people.The five dimensions of an urban systems spatial configuration investigated are including: 1.centrality and the dominance of the vertices, 2. network cohesion, 3. network strength, 4.network symmetry, and 5. communities and levels, which are described systematically andmade measurable due to the values of the indices. The position of the spatial configuration,regardless of spatial scale or the type of flow, ranges across a continuum from purelymonocentric to completely networked.Results and DiscussionIn APF the total number of movement of passengers via inner aerial public transportation fleetin 2006 was 12, 225, 183 According to the first dimension, centrality and power, out of 400possible centrality points, Tehran had value of 271. Mashhad with a centrality of 166.17, whichis substantially less than that for Tehran, was ranked at second. Consequently, it is concludedthat the APF is topologically monocentric. The maximum value for network cohesion can be700 and the APF gains only 457.70 scores and this network with low cohesion differssignificantly from a networked constellation and has greater similarity to mono-polar structures.The maximum value of the third dimension, network strength, can be as high as 300 and theAPF is a more concentrated network with strength of 169.13. The range of the obtained valuesfor the fourth dimension, network symmetry, can be from 0 to 200 and according to obtained  value (193.43), it can be claimed that the air flows of people is symmetrical. The results fromthe fifth dimension, community and levels, shows that for APF, which has more in commonwith the mono-centric model, because of limitation of city organization in superior levels, onlytwo communities of vertices and three levels were detectable.ConclusionThe empirical findings expresses that Tehran is in the first rank and then Mashhad as havingsignificant differences in comparison with other cities at lower spatial levels in that it is theprime city of network; hence the spatial constellation of the network is considerably differentfrom a polycentric. In regard to the second dimension, network cohesion, APF represents lowlevel of cohesion. This occurred because for APF, Mashhad, Bandar Abbas, Ahvaz and Shirazare all located at further geographical distances from the network central city (Tehran) and yetare still able to achieve efficient interactions with Tehran. The third dimension, networkstrength shows that APF is a concentrated network, so it is best described by a monocentricconstellation structure with regard to both topology and weight. According to the results ofnetwork symmetry dimension, the flows of people are symmetrical nationally and annually. Inthe fifth dimension, one of the reasons that clusters are not formed at this level is the absence ofa central city at the median level that can attract significant passenger flows. The expansion ofareal flows in long-distance travels does not allow the formation of median cities close to theirperipheral cities where are accessible by other terrestrial modes of transportation. Thus, urbanhierarchy derived by size-based approach because of observing distinguished dimensions isdifferent from network-based one.}, keywords = {Air Passenger Flow,Iran Urban System,Network-Based Approach,Size-Based Approach}, title_fa = {سازمان فضایی در نظام شهری ایران با استفاده از تحلیل جریان هوایی افراد}, abstract_fa = {مطالعۀ سازمان فضایی نظام‌های شهری و به‎طور خاص روابط بین شهری، در زمینۀ برنامه‌ریزی شهری و علوم منطقه‌ای، مدت مدیدی است که جایگاه ویژه‌ای را به خود اختصاص داده است. اغلب پژوهش‌ها در این خصوص، برخاسته از رهیافت اندازه‌مبنا، معطوف به سطح تمرکز فعالیت‌ها در یک مکان است، درحالی‌که رهیافت تعاملی و شبکه‌مبنا در چهارچوب نگرش‌های نوین، پیوستگی و ارتباطات متقابل بین مکان‌ها را در مطالعۀ سازمان‌یابی فضا مورد توجه قرار داده و ایده‎پردازی روابط متقابل بین شهرها را در تقابل با پذیرش چیدمان سلسله‌مراتبی از فضا قرار می‌دهد که در نظریه‎های سنتی پذیرفته شده بود. از این رهگذر، سازمان‌یابی شهرها را متأثر از آرایش فضایی روابط آنها در فضای جریان‌ها می‌داند، درحالی‌که اغلب پژوهش‌های صورت گرفته در مطالعۀ ساختار نظام شهری کشور، به استفاده از ویژگی‌های مکانی نقاط معطوف بوده و توجه کمتری به استفاده از داده‌های جریانی در چهارچوب رهیافت شبکه‌مبنا و سازمان‌یابی ارتباطی شده است. به همین دلیل در این پژوهش کوشش شده تا با بهره‌گیری از جریان هوایی افراد در سال 1385 و ابزار تحلیل شبکه، سازمان و پیکره‌بندی فضایی حاکم بر نظام شهری کشور تعریف و نتایج به‎دست آمده از آن‌ با سلسله‌مراتب شهری مبتنی بر رهیافت اندازه‌مبنا (ناشی از تعداد جمعیت شهرها در سال 1385) مقایسه شود. نتیجۀ به‎دست‎آمده از تحلیل تعاملات فضایی در قالب پنج مؤلفه، حاکی از آن است که ساختار فضایی حاکم بر نظام شهری کشور، به‎سبب شدت تمرکز و تسلط شهر تهران و محدودیت سازمان‌یافتگی و تعدد شهرها در سطوح فضایی بالاتر، تک‎مرکزی، ناهمبسته، متمرکز و متقارن است؛ به‎طوری که تنها دو سطح، یکی مشتمل بر تهران و دیگری مشتمل بر شهرهای پیرامونی قابل‌ردیابی است. همچنین مقایسۀ سلسله‌مراتب تحلیل شبکه‌مبنا و اندازه‌مبنا از ناهمخوانی نتایج این دو رهیافت با یکدیگر حکایت دارد.}, keywords_fa = {Air Passenger Flow,Iran Urban System,Network-Based Approach,Size-Based Approach}, url = {https://jhgr.ut.ac.ir/article_50597.html}, eprint = {https://jhgr.ut.ac.ir/article_50597_81ed24f07da94e3616a927bb5b911757.pdf} }