Character and Causes of Population Distribution in Shenyang City, China

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1 Chiese Geographical Sciece (3) DOI /s Character ad Causes of Populatio Distributio i Sheyag City, Chia DU Guomig 1, 2, ZHANG Shuwe 1, ZHANG Youqua 1, 2 (1. Northeast Istitute of Geography ad Agroecology, Chiese Academy of Scieces, Chagchu , Chia; 2. Graduate Uiversity of Chiese Academy of Scieces, Beijig , Chia) Abstract: Character of populatio distributio is oe of the focuses studied by urba geography. Usig the fifth atioal cesus data as basic data ad usig areal iterpolatio method, this paper aalyzes character of urba populatio distributio of Sheyag City, Northeast Chia, i terms of three aspects of statistical character, spatial auto-correlatio ad spatial structure. Furthermore, this research aalyzes the factors affectig the populatio distributio of the city. The mai coclusios iclude: 1) There is a obvious structure character of populatio distributio i the grid with a grai of 300m, which is appropriate scale whe researchig populatio distributio i Sheyag City. 2) Urba populatio distributio has the character of assemblig while populatio desity distributio takes o variability i Sheyag City. 3) Populatio desity distributio shows spatial auto-correlatio withi 7.36km. Spatial heterogeeity of populatio desity is low. 4) Urba ceter, populatio distributio baryceter ad populatio desity maximum poits separate each other. Populatio desity distributio has multi-cores character. 5) Layout of govermets, primary schools, middle schools, colleges, hospitals ad marketplaces affects populatio distributio directly. With the icrease of distace to these factors, populatio desity decreases as logarithm. Keywords: populatio desity model; populatio distributio; scale; Sheyag City 1 Itroductio Research o the character of urba populatio distributio is oe of the focuses of wester urba geography. From the 1950s, the research has attracted the attetio of may wester researchers, ad a series of classical theoretical models were put forward. For example, Clark (1951) foud that with the icrease of distace from the city ceter, the urba populatio desity teds to decrease i expoetial. Through the statistical aalysis of more tha 20 cities, he put forward the famous Clark Model. Naroll ad Bertalaffy (1956) ad Stewart ad Wartz (1958) developed the allometric growth model betwee urba populatio ad urba area. Sherratt (1960) ad Taer (1961) raised the ormal desity model (Sherratt Model). Smeed (1961) put forward the egative power-expoetial model (Smeed Model). Newlig (1969) developed coic expoetial model (Newlig Model). After the 1980s, with the developig of wester research o the structure of multi-cores cities, some scholars have put forward the city populatio desity multi-cores model, ad the it became a hot research field (Berry ad Kim, 1993; Small ad Sog, 1994). With the adoptio of the later moder mathematic tool, such as fractal ad the bioic theory, the quatitative expressio ability ad the simulatio experimet methods of urba geography were stregtheed. So some classical mathe- matics models, such as Clark Model, were give the ew explaatio, which makes these models to keep developig (Batty ad Logley, 1994). Recetly, a lot of the theoretical discussio ad case studies have bee doe i Chia (Che ad Xu, 1999; Che, 2000; Feg, 2002; 2004). This paper uses the fifth atioal cesus data as basic data, the data of first floor area of the residetial houses as auxiliary data to spatialize populatio data, ad uses regular grid to resample populatio distributio ad methodology of ladscape ecology, ad geo-statistics to research character of urba populatio distributio, aalyze the appropriate scale of populatio desity, ad simulate the spatial distributio of populatio desity of Sheyag City, Northeast Chia. I the last, this research aalyzes factors affectig populatio distributio, which iclude govermets, primary schools, middle schools, colleges, hospitals ad marketplaces. 2 Study Area ad Data Sources Sheyag City, capital of Liaoig Provice, lies i the south of Northeast Chia. The total area of Sheyag is 12,980km 2. Util the ed of the year 2000, the built-up area was 217km 2. The terrai is maily plai, with a average elevatio of 50m. The Huhe River flows through the south of the city. Sheyag City is the ceter Received date: ; accepted date: Foudatio item: Uder the auspices of Kowledge Iovatio Program of Chies Academy of Scieces (No. KZCX2-SW-210-1) Biography: DU Guomig (1978 ), male, a ative of Nigcheg of Ier Mogolia, Ph.D. cadidate, specialized i GIS ad RS applicatio. mgdgm@126.com

2 218 of polity, ecoomy ad culture of Liaoig Provice. It is also oe of the most importat heavy idustry cities i Chia. Util the fifth cesus, the urba populatio of Sheyag was The research rage is a rectagles regio that icludes urba area ad suburb area. The total study area is 336km 2, ivolvig 981 cesus sectios. The source data of this research iclude the fifth atioal cesus ad GIS spatial data. The cesus data was supplied by populatio statistic departmet. The spatial data, icludig the cesus sectios data, the data of first floor of the residetial houses ad the basic urba geographical iformatio data, are mapped ad supplied by the related departmets ad are up to precisio of mappig. The cesus data ad spatial data, which are itegrated together, make up of GIS database of this research. 3 Methods 3.1 Spatializig cesus data I the research, the process of spatializig cesus data ad calculatig populatio desity icludes three steps as follows: 1) To establish relatio betwee the cesus data ad cesus sectios by the cesus sectio code. 2) To spatialize populatio cesus data usig areal iterpolatio (Pa ad Liu, 2002). This step icludes overlayig the vector data of the first floor of the residetial houses with the cesus sectios data, calculatig the area of the first floor i every cesus sectio ad the populatio desity of first floor i every cesus sectio. The calculatio formula is as follows: D i =P i /A i (1) where D i is populatio desity of the first floor of the residetial houses i the ith cesus sectio; P i, the quatity of populatio i the ith cesus sectio; A i, the total area of the first floor of the houses i the ith cesus sectio. 3) To use the regular grid to resample, ad to calculate the quatity ad desity of populatio for every grid. I Arc/Ifo eviromet, we overlay the grid data with the first floor data ad calculate the quatity ad desity of populatio for every grid. The formula is as follows: P = A D (2) j i ij D j =P j /A j (3) where P j represets the quatity of populatio i the jth grid; A ij, the area of the first floor of the residetial houses that belogs to the ith cesus sectio ad is located i the jth grid; D ij, the desity of the first floor of the residetial houses that belogs to the ith cesus sectio ad is located i the jth grid; D j, the desity of populatio of the jth grid; A j, the area of the jth grid. Accordig to ladscape ecology, we call the side of grid as grai (G). I order to choosig appropriate scale, grais i the research iclude te kids from 100m to 1000m. 3.2 Spatial statistical aalysis methods Statistics Statistics ca be used for aalyzig populatio desity. ij DU Guomig, ZHANG Shuwe, ZHANG Youqua The statistics idexes used i this research iclude mea, maximum (max), miimum (mi), ad stadard deviatio (SD) Ladscape idex method Ladscape idex is a basic tool of ladscape ecology for researchig spatial patter. The populatio desity is differet from the lad use, ad ca ot be classified, but it ca be grouped accordig to the desity rage, ad the groups ca take the place of the classes. This research puts the desity that is zero ito oe group, ad other desities are grouped i a iterval of 100 perso/ha. The we calculate ladscape richess idex (R), Shao-weaver ladscape diversity idex (H), ladscape eveess idex (E) ad ladscape domiace idex (D) (Wu, 2000) Geo-statistics O the basis of regioalized variable theory, geostatistics researches spatial pheomea with structured ad stochastic features. Geo-statistics has two mai fields: 1) aalysis of spatial correlatio ad variatio of regioalized variable; 2) spatial iterpolatio (Wag, 1999). The semi-variace fuctio ad its model are the foudatio of geo-statistics research. Accordig to structure character of the semi-variace of populatio desity, this paper chooses ordiary Krigig to model spatial distributio of populatio desity ad draw populatio desity isolie. 3.3 Factors aalysis method I Sheyag built-up area, spatial heterogeeity of mai physical geographical elemets is small, such as climate, physiogomy ad hydrology. Urba ifrastructure, such as commuicatio, water supply, heatig, power supply, ca satisfy livig of the residets. These elemets ca ot limit populatio distributio. But most public sectors distributio is asymmetrical, such as govermets, schools ad hospitals, which have close relatios with livig of the residet. So this research chooses govermets, primary schools, middle schools (icludig high schools), colleges, hospitals, marketplaces ad park, greebelts as the factors affectig populatio distributio. Data disposig icludes followig steps: Firstly, to pick the elemets affectig populatio distributio from the database, simplifig govermets, primary schools, middle schools, colleges, hospitals ad marketplaces as poits, ad icorporatig parks ad greebelts ito oe polygo cover. Secodly, to create multi-rigs buffer data for every elemet with 250m-distace, ad erasig them out of the research regio. Thirdly, to overlay every buffer data with the vector data of the first floor of the residetial houses, the calculatig area, populatio quatity ad desity for every rig i every buffer usig formulae (4) ad (5). P = A D (4) r ir ir i D r =P r / A r (5) where P r represets populatio amout i the rth rig; A ir, the area of the first floor of the residetial houses that

3 Character ad Causes of Populatio Distributio i Sheyag City, Chia 219 belogs to the ith cesus sectio ad is located i the rth rig; D ir, the populatio desity of the first floor of the residetial houses that belogs to the ith cesus sectio ad is located i the rth rig; D r, the populatio desity of the rth rig; A r, the area of the rth rig. 4 Results ad Aalysis 4.1 Choosig appropriate scale The problem of choosig the appropriate scale is ivolved whe usig grid aalysis techique to aalyze character of populatio distributio. This research cofirms the appropriate scale by ladscape idexes. It ca be show i Table 1 that whe G is 100m, R is 20; whe G icreases to 300m, R decreases to 10; with the icrease of G, R decrease a littile. There is a obvious iflexio i the curve of R (Fig. 1). The Shao-weaver ladscape diversity idex (H), which is based o the iformatio etropy theory, decreases with the icrease of the grai. The ladscape eveess idex (E) ad domiace idex (D) fluctuate with the icrease of G, ad the maximum E ad miimum D appear respectively whe the grai is 300m (Fig. 1). This suggests that there is a obvious structure feature whe G is 300m for populatio desity, ad 300m is the appropriate scale to research populatio distributio i Sheyag. 4.2 Character of populatio distributio Statistical character Populatio desity statistics whe G is 300m are listed i Table 2. It ca be see from Table 2 that populatio desity of Sheyag is dispersed. SD/Mea=1.58 idicates that populatio desity distributio has variability. I geeral, if SD 2 /Mea is more tha 1, populatio dis- Table 1 Ladscape idexes of populatio desity G (m) R H E D tributio exhibits covergece. Now SD 2 /Mea arrives to , which illumiates that the covergece of populatio is very high. For aalyzig the degree of populatio covergece, we draw a Lorez curve of populatio distributio (Fig. 2). It ca be see that the curve is segregative with the rectagle diagoal, which suggests that populatio distributio has character of o-equilibrium ad assemblig. The poit (29.57%, 88.30%) is a obvious iflexio of the curve, which illumiates that about 90% of populatio resides i 30% area of the research regio, where populatio is dese; ad about 10% of populatio resides i the other 70% area of the research regio, where populatio is sparse Character of spatial auto-correlatio Semi-variace fuctio ad its parameters are listed i Table 3 whe G is 300m. It ca be discovered that: 1) semi-variace fuctio accords with spherical model; 2) there is spatial auto-correlatio withi a special rage for populatio desity, which decreases with the icrease of Fig. 1 Relative ladscape idexes

220 DU Guomig, ZHANG Shuwe, ZHANG Youqua Table 2 Populatio desity statistics (G=300m) Sample umber Mea (perso/ha) Max (perso/ha) Mi (perso/ha) SD (perso/ha) SD/ Mea SD 2 / Mea 3740 107.21 882.

2 Lorez curve of populatio distributio i Sheyag Table 3 Semivariogram model ad parameter (G=300m) Nugget Partial still Still Nugget/ still a (m) 900 Spherical 11649 25568 37217 0.3130 7355.

4 220 DU Guomig, ZHANG Shuwe, ZHANG Youqua Table 2 Populatio desity statistics (G=300m) Sample umber Mea (perso/ha) Max (perso/ha) Mi (perso/ha) SD (perso/ha) SD/ Mea SD 2 / Mea h (m) Model Fig. 2 Lorez curve of populatio distributio i Sheyag Table 3 Semivariogram model ad parameter (G=300m) Nugget Partial still Still Nugget/ still a (m) 900 Spherical Notes: h represets lag distace; a represets auto-correlatio scale distace. But there is o spatial auto-correlatio out of the special rage for populatio desity. The special distace is auto-correlatio scale (a). The auto-correlatio scale is 7.36km i the research regio. The ugget is 11,649, which suggests that part of spatial heterogeeity of populatio desity is resulted from radom factors. This part takes effect maily withi 900m. The still is 37,217 ad the partial still is 25,568, which meas that part of heterogeeity is resulted from structured characters ad spatial auto-correlatio. This part takes effect maily betwee 0.9km ad 7.36km. The score of ugget ad still is 0.313, which meas that spatial heterogeeity that resulted from radom factors accouts for 31.3%, spatial heterogeeity that resulted from structure character ad spatial auto-correlatio accouts for 68.7%. The latter is major of the whole spatial heterogeeity of populatio desity Character of spatial structure O the basis of the character of roads distributio i Sheyag City, this research regards radiatio ceter of city roads as urba ceter. Moreover, this research calculates populatio baryceter accordig to grid data whose grai is 300m, ad draws populatio desity map (Fig. 3). The populatio baryceter is expressed as follows: ( i i)/ i i= 1 i= 1 X = C X C Y = ( C Y )/ C (6) i i i i= 1 i= 1 where X ad Y represet the populatio baryceter coordiate, C i represets the populatio quatity of the ith cell. X i ad Y i represet the ceter coordiate of the ith cell. For showig character of populatio distributio clearly, based o Fig. 3 ad semi-variace aalysis, we use ordiary Krigig to iterpolate, ad create populatio desity simulatio map (Fig. 4). As show i Fig. 3 ad Fig. 4, populatio baryceter ad urba ceter are ot superposed, whose distace is 1.61km. Urba ceter, populatio baryceter ad populatio desity maximum poits are separate. Populatio distributio shows a multi-cores structure. The close isolies are elliptic i the populatio desity high-valued regios. There is a U suke regio of populatio desity i the wester of the city, ad there is a low-valued regio of populatio i the ortheast of the city. Accordig to the above-metioed, populatio distributio takes o complicated multi-cores structure. Fig. 3 Populatio desity map of Sheyag

Character ad Causes of Populatio Distributio i Sheyag City, Chia 221 Fig. 4 Populatio desity simulatio map of Sheyag 4.

5, populatio desity fluctuates with the icrease of distace to parks ad greebelt, but the period is ot certai.

For describig these elemets impacts o populatio distributio accurately, i the light of Table 3, this research choose liearity, logarithm, expoet ad power models to simulate populatio desity ad

5 Character ad Causes of Populatio Distributio i Sheyag City, Chia 221 Fig. 4 Populatio desity simulatio map of Sheyag 4.3 Factors affectig populatio distributio Based o the results calculated by sector 3.3, the curves of relatioship betwee distace to the elemets ad populatio desity are draw (Fig. 5). As show i Fig. 5, populatio desity fluctuates with the icrease of distace to parks ad greebelt, but the period is ot certai. For the other elemets, populatio desity decreases with the icrease of distace to these elemets, ad there are obvious iflexios aroud 1km. For describig these elemets impacts o populatio distributio accurately, i the light of Table 3, this research choose liearity, logarithm, expoet ad power models to simulate populatio desity ad distace for every elemet, ad choose the best model whose R 2 is the greatest (Table 4). It ca be show i Table 4 that all the best models are logarithm model ad all R 2 are more tha 0.86, which illumiates that the effects of models simulatig are fie. These models prove that the distributio of govermets, primary schools, middle schools, colleges, hospitals ad marketplaces affects populatio distributio directly. With the icrease of distace to these elemets, populatio desity decrease sharply. Whe the distace arrives at a certai extet, the rate of populatio desity decreasig becomes slower, ad the populatio desity treds to zero. Moreover, whe overlayig populatio desity map with distributio map of these elemets, it ca be discovered that these factors assemble i the regios with high populatio desity. 5 Coclusios Usig the fifth atioal cesus data as basic data ad usig areal iterpolatio method, this paper aalyzes character of urba populatio distributio of Sheyag City, Northeast Chia. Furthermore, this paper aalyzes the factors affectig the populatio distributio of the city. The mai coclusios of this paper iclude: Firstly, there is a obvious structure character of populatio distributio i the grid with a grai of 300m Factor Fig. 5 Relatio curves of distace to every elemet ad populatio desity Table 4 Coditios of every factor ad populatio desity-distace model Number Rig umber Govermet Primary school Middle school College Hospital Marketplace Model R 2 y = L(x) y = L(x) y = L(x) y = L(x) y = L(x) y = 78.16L(x) Note: y represets populatio desity (perso/ha); x represets the earest distace to the relevat factor i ay poit of the research regio (km) which is appropriate scale whe researchig populatio distributio i Sheyag City. Secodly, urba populatio distributio has character of assemblig while populatio desity distributio takes o variability i Sheyag City. Ad 90% of populatio resides i about 30% of area of the research area. Thirdly, spatial auto-correlatio scale of populatio

6 222 desity is 7.36km. Spatial heterogeeity of populatio desity results from spatial auto-correlatio maily. Fourthly, urba ceter, populatio distributio baryceter ad populatio desity maximum poit separate each other, ad populatio desity takes o multi-cores character. Fifthly, the distributio of primary schools, middle schools, colleges, hospitals ad marketplaces affects the populatio distributio directly. With the icrease of distace to these elemets, populatio desity decreases as logarithm. These elemets assemble i the regios with high populatio desity. Refereces Batty M, Logley P A, Fractal Cities: A Geometry of Form ad Fuctio. Lodo: Academic Press, Harcourt Brace & Compay. Berry B J, Kim H M, Challeges to the moocetric model. Geographical Aalysis, 25: 1 4. Che Yaguag, Xu Qiuhog, Studies o the fractal geometric model of allometric growth relatioships betwee area ad populatio of urba systems. Joural of Xiyag Teachers College (Natural Sciece Editio), 12(2): (i Chiese) Che Yaguag, Derivatio ad geeralizatio of Clark s model o urba populatio desity usig etropy Maximizig methods ad fractal ideas. Joural of Cetral Chia Normal Uiversity (Nat. Sci.), 34(4): (i Chiese) Clark C, Urba populatio desities. Joural of Royal Statistical Society, l14: Feg Jia, Modelig the spatial distributio of urba popu- DU Guomig, ZHANG Shuwe, ZHANG Youqua latio desity ad its evolutio i Hagzhou. Geographical Research, 21(5): (i Chiese) Feg Jia, Restructurig of Urba Iteral Space i Chia i the Trasitio Period. Beijig: Sciece Press. (i Chiese) Naroll R S, Bertalaffy L Vo, The priciple of allometry i biology ad the social scieces. Geeral Systems Yearbook, 1: Newlig B E, The spatial variatio of urba populatio desities. Geographical Review, 59: Pa Zhiqiag, Liu Gaohua, The research progress of areal iterpolatio. Progress i Geography, 21(2): (i Chiese) Sherratt G G, A model for geeral urba growth. I: Churchma C W et al. (eds.).maagemet Scieces,Model ad Techiques:Proceedigs of the Sixth Iteratioal Meetig of Istitute of Maagemet Scieces (Vol. 2). Elmsford, N Y: Pergamo Press, Small K A, Sog S, Populatio ad employmet desities: Structure ad chage. Joural of Urba Ecoomics, 36: Smeed R J, The traffic problem i tows. I: Machester Statistical Society Papers. Machester: Norbury Lockwood. Stewart J Q, Wartz W, Physics of populatio distributio. Joural of Regioal Sciec, 1: Taer J C, Factors affectig the amout travel. I: Road Research Techical Paper No.51. Lodo: Departmet of Scietific ad Idustrial Research. Wag Zhegqua, Geostatistics ad It's Applicatio for Ecology. Beijig: Sciece Press. (i Chiese) Wu Jiaguo, Ladscape Ecology-patter, Process, Scale ad Hierarchy. Beijig: Higher Educatio Press. (i Chiese)

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