20402_02_Rusanen Georeferenced data as a tool for monitoring the concentration of population in Finland in 1970–1998 JARMO RUSANEN, TOIVO MUILU, ALFRED COLPAERT AND ARVO NAUKKARINEN Rusanen, Jarmo, Toivo Muilu, Alfred Colpaert & Arvo Naukkarinen (2003). Georeferenced data as a tool for monitoring the concentration of population in Finland in 1970–1998. Fennia 181: 2, pp. 129–144. Helsinki. ISSN 0015- 0010. Changes in the distribution of population in Finland over the period 1970– 1998 are examined in terms of a co-ordinate system of 1 x 1 km grid cells. The results indicate that this system provides suitable areal units for a variety of statistical and GIS methods aimed at describing and explaining the spatial distribution of population. The system is capable of yielding more detailed information than heretofore on topics such as the concentration of population in the urban centres of Finland – a process that has been going on since the beginning of the last century, but has slowed down noticeably in the recent years. Jarmo Rusanen, Toivo Muilu, Alfred Colpaert & Arvo Naukkarinen, Depart- ment of Geography, PO BOX 3000, FIN 90014 University of Oulu, Finland. E- mail: jarmo.rusanen@oulu.fi. MS received 07 January 2003. Introduction Demographic research has a long tradition with- in geography and represents a discipline that is eminently suited to the study of the spatial distri- bution of population and its changes. The results of these studies are required for planning purpos- es in many sectors of the society, e.g. determina- tion of the capacity and location requirements for various public services at the national, regional or local level. Although it is primarily the author- ities that have been interested in the direction of demographic trends, it is by no means a matter of indifference for individual citizens or families whether they live in an area of expanding or di- minishing population. The general image of an area is to a considerable extent shaped by trends in population, as well as with structural changes of the area. There is thus an obvious need for sta- tistical data that are both up to date and geograph- ically more detailed than earlier, and for precise interpretations of such data. This poses new chal- lenges not only for the producers and users of the statistics but also for those engaged in develop- ing and applying analytical and interpretative methodologies. The geographical examination of population distributions and their temporal changes has typ- ically relied on notions such as spatial concen- tration and deconcentration (Lipshitz 1996; Borgegård et al. 1995), or urbanization and coun- terurbanization (Håkansson 2000), while migra- tion research has adopted perspectives such as that of the ‘turnaround’ phenomenon (Long & Nucci 1997; Lewis 2000). The actual terms in use vary not only according to the theoretical basis from which the research sets out but also in rela- tion to the volume of migration concerned and its temporal duration. Our picture of the spatial concentration and agglomeration of population in Finland has large- ly been shaped by the publications of Hustich (1977) and Alestalo (1983). More recently, how- ever, the present authors have discussed changes in the settlement structure and the concentration of population with the aid of georeferenced data and GIS methods (see Naukkarinen et al. 1993; Rusanen et al. 1997). As pointed out by e.g. Håkansson (2000), re- search into the distribution of population can be greatly affected by the employed geographical unit, so that models that apply at one spatial lev- 130 FENNIA 181: 2 (2003)Jarmo Rusanen, Toivo Muilu, Alfred Colpaert and Arvo Naukkarinen el do not necessarily hold good at another. One particularly difficult problem concerns boundary changes, which indicates that census statistics for different years do not necessarily apply to the same areal units and therefore, cannot be com- pared easily (Howenstine 1993; Openshaw 1995; Rees 1998). The requirements placed on population statis- tics and the usefulness of the data available can vary greatly from one group of users to another. Public authorities, for instance, are accustomed to using statistical means and definitions ex- pressed in terms of administrative areas and de- ductions made from these when they require in- formation on which to base their decisions. Re- searchers, in contrast, prefer to go back to the sources of the original raw data in order to test their hypotheses and construct their models. For this reason we will attempt to analyse and exam- ine demographic data using various methods in terms of both administrative and non-administra- tive areal units, and to evaluate the subsequent results. Aims, data and methods We set out here to describe 1) the changes in pop- ulation that have taken place within the spatial and settlement structure of Finland by means of 1 x 1 km grid cell data, 2) the methods available for the analysis of population data, and 3) the fac- tors highlighted by the grid cell method that can- not be identified when using administrative areal units. Finally, the usefulness of the resulting in- formation for the purposes of demographic re- search will be evaluated. Georeferenced data on Finland are available at many spatial levels. In practice, any individual citizen can be assigned a set of coordinates de- scribing the geographical location of the house in which he or she lives. The resulting data can be aggregated to represent higher-level units, e.g. postal districts, parts of municipalities, whole municipalities, groups of municipalities or the NUTS hierarchy as used by the EU. It must be re- membered, however, that the above-mentioned problem of comparability over time emerges in the case of these areal units whenever adminis- trative areas are combined or boundaries are al- tered. On the other hand, the fact that the initial information is available at the individual level is regarded as a significant advantage of GIS meth- ods (Martin & Higgs 1997; see also Openshaw & Turton 1996). Thus, the principal units employed here are the 1 x 1 km grid cells defined in the data produced by Statistics Finland for the years 1970, 1980 and 1990–1998 (see Rusanen et al. 1997). These grid cells are of fixed location and are independent of any changes in administrative boundaries. Statis- tical information on human activities in Finland has been available annually since 1987. Current methods enable Statistics Finland to revise their georeferenced population data very quickly, so that figures for the population on 31st December are available by the end of the following Febru- ary, together with statistics for the individual mu- nicipalities. This annual information is based on registers, so that no separate population census is necessary as in the USA, for example (see Crews 2000). The second basic areal unit employed here is the municipality, or independent local govern- ment district. These districts have numerous rights and obligations that define them as administra- tive entities, including the right to levy taxes (Min- istry of the Interior 2000). In accordance with the above principle, the populations of the munici- palities are calculated here from the grid cell fig- ures, and for this reason the figures differ slightly from those quoted in the official statistics, as for instance in 1998, 1.42% of the national popula- tion could not be assigned coordinates on the ba- sis of their place of residence. However, this dis- crepancy can be assumed not to affect the results. It should be noted that we are not concerned here with studying the potential factors responsi- ble for demographic trends in particular areas, e.g. birth-rates, mortality or migration – topics which have traditionally been to the fore in pop- ulation geography (Ogden 1998; 1999). Instead, we focus on describing solely the concentration of population. This is defined here in two ways: as an increase in population density per square kilometre when using grid cell data, and as an in- creasingly larger proportion of the population liv- ing in a progressively smaller number of munici- palities. Data on population changes in the 1 x 1 km grid cells and municipalities are analysed here by a number of methods, and assessments are made as to whether these methods yield similar or di- vergent results. The methods tested include the Gini Coefficient, which is more commonly used for analysing the spatial distribution of income FENNIA 181: 2 (2003) 131Georeferenced data as a tool for monitoring the… rates (see Chakravorty 1994) rather than popula- tion (see Bradford & Kent 1986; Lovell-Smith 1993). In addition, the concentration of popula- tion is described in terms of mean values and the Moran and Geary Indices used in version 8.0 of the Arc/Info software. Changes in population are also described by reference to deciles and by clas- sification of the ‘spatial demographic structure’. Long-term patterns are visualized by means of a rank size model and the kriging interpolation method contained in version 8.0 of Arc/Info. The Hoover Index that is frequently used in studies of population concentration (see Borgegård et al. 1995; Long & Nucci 1997) is not employed here, as the emphasis is on analysis at the grid cell lev- el rather than at the municipality level. Decile analysis involves ranking the data units in size order from largest to smallest with respect to the studied variable, and dividing them into ten equal groups in terms of population described by the variable, regardless of whether the areal unit is a grid cell or a municipality. Population concentration as reflected in the Moran and Geary indices and the Gini coefficient Population density in Finland in 1998 relative to land area was very low by European standards, only 16.9 inhabitants per square kilometre. If, however, we use the grid cell material to calcu- late the mean density for inhabited cells only, we see that the density has increased steadily over the period examined here, and is now approach- ing 50 inhab./km2 (Table 1). The Moran and Geary methods allow a spatial autocorrelation index to be determined for the grid cell material as follows: when the Moran In- dex is positive and the Geary Index varies in the range 0–1 the distribution of population can be described as ‘similar’, ‘regionalized’, ‘smooth’ or ‘clustered’. If the Moran Index is negative and the Geary Index greater than 1, the corresponding terms are ‘dissimilar’, ‘contrasting’ and ‘checker- board’ (for details, see Arc/Info User Manual 2000). In the present case, the gradual increase in the Moran Index and the simultaneous de- crease in the Geary Index lend further support to the impression gained from the previous table of a process of consolidation of the inhabited area rather than a scattering or dispersal of population (Table 2). One typical technique employed to describe evenness or concentration in the distribution of population is the Lorenz diagram (Alestalo 1983), or its derivative, the Gini Coefficient (Fainstein 1996). Regardless of whether we use grid cells or municipalities as the areal units, the obtained Gini Coefficients indicate a concentration of popula- tion (Table 3), although the higher value of the grid cell material as compared to the municipali- ty level also indicates the essentially local nature of this concentration. The fact that the majority of the population of Finland is located within a relatively small number of grid cells is indicative of the low proportion of built-up areas within the country’s total settled area. Measured in both of the above ways, the rate of change was greatest in the 1970’s, an observa- tion that confirms the general impression regard- ing the concentration of population in Finland. It is consistent with the results of the examination by deciles published by Alestalo (1983). On the other hand, analysis of the trend over the last two decades in terms of the Gini Coefficient provides deviant results for the two sets of areal units. The rate of population concentration apparently has slowed down when assessed in terms of the grid Table 1. Number of inhabited grid cells and mean population density in Finland in 1970–1998 (Data: Statistics Finland). 1970 1980 1990 1992 1994 1996 1998 Number of inhabited grid cells 110477 104540 103242 103020 103036 103045 102873 Inhab./km2 41.3 44.1 47.8 48.4 48.9 49.1 49.4 Table 2. Moran (I) and Geary (C) Indices in 1970–1998 (Data: Statistics Finland). Year 1970 1980 1990 1992 1994 1996 1998 I 0.543 0.531 0.568 0.570 0.581 0.590 0.597 C 0.427 0.435 0.400 0.394 0.384 0.377 0.370 132 FENNIA 181: 2 (2003)Jarmo Rusanen, Toivo Muilu, Alfred Colpaert and Arvo Naukkarinen cell data, being only 1.1% in the 1990’s, where- as the figures for the municipalities indicate ac- celeration with a terminal rate of 3.5%. The result obtained from the grid cell data may indicate a decreasing trend in population concen- tration in the densest areas, the pattern being at- tributable to the exclusion of uninhabited grid cells and the concentration of population in a constantly decreasing number of cells and a more restricted geographical area. This trend, which is largely internal to individual municipalities, fails to be reflected in the analyses based on munici- palities as the areal units. Decile analysis Decile analysis employs divisions of the total ma- terial into tenth parts. It can be regarded as a flex- ible, non-given means of classification, and since the boundaries of the deciles tend to vary from one year to the next, the method is well suited to studies of concentration or dispersal, e.g. in pop- ulation or incomes. According to Alestalo (1983), the population of Finland was fairly evenly dis- tributed over the deciles at the end of the 19th century, the agrarian society of the time showing little agglomeration of the population into urban centres. From that time onwards, however, the population gradually became concentrated in a smaller number of municipalities (Table 4), so that by the 1970’s, half of the country’s population lived in 52 municipalities, 10.1% of their total number. The trend continued so that in 1998, the corresponding figure was 33 municipalities, i.e. 7.3% of the total. Part of this effect may be attrib- uted to the amalgamation of municipalities with- in the system of local government, but the princi- pal factor has without doubt been the actual con- centration of population within a progressively smaller number of towns and cities (Rusanen et al. 2000). Is this concentration visible in the grid cell data? For answering this, a decile analysis com- parable to that in Table 4 is presented in Table 5. The deciles indeed indicate a continuation of the concentration process, so that half of the coun- try’s population (the population of deciles 1–5) occupied a total of 1541 km2 in 1970, 1167 km2 in 1980, 1294 km2 in 1990 and 1284 km2 in 1998. The 1970’s were a period of heavy popula- tion concentration, whereas from the end of that decade onwards Finland was affected by a ‘turn- around’ phenomenon, as noted by several authors (Kauppinen 2000). This process was experienced in many western countries, entailing above all a Table 3. Concentration of population as shown by the Gini Coefficients for the years studied and percentage change over the period 1970–1998 (Data: Statistics Finland). Year Areal unit 1970 1980 1990 1998 Grid cell 0.78558 0.83450 0.85365 0.86324 Municipality 0.59228 0.62145 0.62962 0.65186 Change in Gini Coefficient (%) 1970–1980 1980–1990 1990–1998 Grid cell 6.2 2.3 1.1 Municipality 4.9 1.3 3.5 Table 4. Concentration of population by deciles of munici- palities in 1970, 1980, 1990 and 1998 (Data: Statistics Fin- land). Number of municipalities Year Decile 1970 1980 1990 1998 1 1 1 2 1 2 4 4 3 3 3 6 5 5 4 4 15 10 10 9 5 26 20 18 16 6 38 29 27 23 7 50 42 40 38 8 66 58 57 56 9 97 88 87 88 10 212 204 206 214 Total 515 461 455 452 FENNIA 181: 2 (2003) 133Georeferenced data as a tool for monitoring the… decline in the popularity of urban areas as living environments for families with children. The inhabited area of Finland in 1998 amount- ed to ca. 30.4% of the total surface area of 338 145 km2, with a consistent decline of this propor- tion from one decade to the next since 1970. The most pronounced decline, almost 6000 km2, took place during the 1970’s, although it has also been claimed that the material for 1970 contained some errors in the coordinates determined for in- dividual dwellings and that the actual net de- crease was not necessarily as great as this. It should also be noted that the trend was a rela- tively steady over the period 1990–1998 relative to the 1980’s, although data on the final years of the decade are still lacking. Changes may also be observed in the popula- tion densities for the deciles (Table 6). The high- est densities of all were recorded in deciles 1 and 2 in 1970, when Finland was experiencing a pro- nounced migration from the countryside into the towns and also abroad, primarily to Sweden (see Kauppinen 2000). At that time the mean popula- tion density in the top decile was around 9700 inhab./km2, whereas the corresponding figure in 1998 was about 6200. The maximum population density was reached in Helsinki, the capital. In the 1970 data the density peaked at 29 234 in- hab./km2, whereas the figure for 1998 showed a reduction of more than a third, 19 172 inhab./ km2. A number of factors can be identified that con- tributed to the reduction of population density in Finland over the study period. The most signifi- cant factor was the transfer in the urban centres from dwellings to other uses, mainly offices and commercial premises. Other factors were chang- es in the structure of households, including reduc- tions in the average family size and the number of families with children and an increase in the number of single-person households. It should be pointed out, however, that the mean population density of the two most densely inhabited deciles began to increase again in the 1990’s, partly on account of the efforts made to fill in the settlement pattern in built-up areas in accordance with the principles of sustainable de- velopment. Andersson (1988) recognizes four stages in the development of towns in Finland: urbanization, suburbanization, disurbanization and reurbaniza- tion. Urbanization stage refers to the growth of a central urban nucleus, while the suburbanization stage involves a slowing down and eventually ces- sation of this trend. At the disurbanization stage, Table 5. Numbers of inhabited grid cells by deciles in 1970, 1980, 1990 and 1998 (Data: Statistics Finland). 1970 1980 1990 1998 Inhab. km2 Decile N N N N in 1998 1 densest 47 66 84 82 4171–19172 2 settlement 116 133 159 158 2633–4170 3 207 200 234 234 1795–2632 4 384 297 336 334 1257–1794 5 787 471 481 476 881–1256 6 1 856 825 751 721 536–880 7 4 992 1 928 1 420 1 299 267–535 8 11 290 6 816 4 635 3 813 70–266 9 sparsest 22 331 19 590 16 579 14 980 20–36 10 settlement 68 462 74 209 78 561 80 770 1–19 Number of grid cells 110 472 104 535 103 240 102 873 Table 6. Population density by deciles in 1970, 1980, 1990 and 1998 (Data: Statistics Finland). Inhab. km2 Decile 1970 1980 1990 1998 1 9703 6980 5876 6202 2 3932 3464 3104 3219 3 2203 2303 2109 2173 4 1188 1551 1469 1523 5 579 978 1026 1068 6 246 558 657 705 7 91 239 348 392 8 40 68 106 133 9 20 24 30 34 10 7 6 6 6 134 FENNIA 181: 2 (2003)Jarmo Rusanen, Toivo Muilu, Alfred Colpaert and Arvo Naukkarinen the trend is reversed, until the reurbanization stage marks new growth in the urban nucleus. It is interesting to consider how these stages might be reflected in an empirical decile analysis. The urbanization stage seems to have taken place in Finland before 1970, as the population of the most densely inhabited central areas (deciles 1 and 2) began to decline after that time. Hence, the 1970’s and 1980’s may be assigned to the suburbanization and disurbanization stag- es, as these figures in particular declined mark- edly at first and then levelled out somewhat in the 1980’s, when the changes were less pro- nounced in other respects, too. The 1990’s repre- sent the reurbanization stage, in which the popu- lation of the most densely inhabited areas again started to increase. It is important to bear in mind when evaluat- ing these findings that the stages are distinguished on the strength of only a single variable. A more precise consideration would call for an internal analysis of the structure of the ten largest cities, for example, and also other information relevant to the growth of urban areas, e.g. their develop- ment and planning policies. Population changes by deciles in 1990–1998 Dual trends in population density and in the number of inhabited grid cells are observable dur- ing the 1990’s, the cut-off point being reached in 1993. The minimum area occupied by half of the population of Finland, i.e. deciles 1–5, increased numerically over that time (Table 7a), implying a slight decline in population density in the urban nuclei and suburbs (Table 7b). From 1993 on- wards, the trend towards denser communities can be observed, although not quite amounting to the figures recorded in 1970 and 1980. The most sparsely populated rural areas (decile 10) increased in number throughout the 1990’s, whereas their mean population density remained more or less stable. The increase may be attribut- ed almost entirely to reductions in the population of some grid cells previously contained in decile 9, representing the rural areas proper, causing their transfer to decile 10. The reversal in the trend in 1993 is probably linked to the fact that this was the worst year of the economic recession in Finland, i.e. the peri- Table 7. Changes in the number of grid cells (A) and population density (B) in the 1990’s (Data: Statistics Finland). A. Number of grid cells Trend Decile 1990 1991 1992 1993 1994 1995 1996 1997 1998 1990– 1994– 1990– 1993 1998 1998 1 84 85 86 86 85 84 83 82 82 + – 2 159 162 164 164 163 161 160 160 158 + – – 3 234 238 241 241 240 239 236 235 234 + – 0 4 336 339 342 344 343 339 338 336 334 + – – 5 481 484 487 488 485 482 480 477 476 + – – 6 751 751 750 751 744 736 728 724 721 0 – – 7 1420 1406 1400 1390 1364 1345 1329 1316 1299 – – – 8 4635 4500 4409 4332 4214 4096 4012 3915 3813 – – – 9 16579 16305 16105 15930 15746 15548 15380 15204 14980 – – – 10 78561 78815 79038 79314 79652 80007 80299 80583 80770 + + + B. Population density inhab./km2 1 5876 5840 5802 5831 5923 6015 6100 6191 6202 – + + 2 3104 3064 3043 3058 3089 3138 3165 3173 3219 – + + 3 2109 2086 2071 2081 2098 2114 2145 2160 2173 – + + 4 1469 1464 1459 1458 1468 1491 1498 1511 1522 – + + 5 1026 1026 1025 1028 1038 1048 1055 1064 1068 + + + 6 657 661 665 668 677 687 695 701 705 + + + 7 348 353 356 361 369 376 381 386 391 + + + 8 106 110 113 116 119 123 126 130 133 + + + 9 30 30 31 31 32 32 33 33 34 + + + 10 6,3 6,3 6,3 6,3 6,3 6,3 6,3 6,3 6,3 0 0 0 FENNIA 181: 2 (2003) 135Georeferenced data as a tool for monitoring the… od in which the unemployment peaked. Similar- ly, housing production declined steadily, to reach its lowest ebb in 1994. This was followed by a period of economic recovery (SVT 1999), with a new stimulation of building activity, especially in the metropolitan area of Helsinki and other large municipalities. This trend was accompanied by a rise in population densities, as the housing capac- ity of the built-up areas increased while the land areas concerned remained more or less constant. The increased housing density was hence reflect- ed in the population density. The above observation demonstrates the usabil- ity of the grid cell data as an aid in monitoring changes in spatial structure, and potentially achieving detailed explanation. This method al- lows, for instance, observing small changes in population within a municipality very easily. The spatial demographic structure in 1970–1998 The repeatability of the decile method allows it to be applied to any country or any areal unit, and any researcher can arrive at the same results. It should be remembered, however, that such ac- curate geofererenced data are available in select- ed countries only. We will turn our attention now to structural features of the spatial distribution of population and the changes detected in the dis- tribution in the cross-sectional data for 1970, 1980, 1990 and 1998, with particular reference to developments during the 1990’s. The classifi- cation employed may be referred to as the ‘spa- tial demographic structure’, as it represents an at- tempt to describe the relation between popula- tion density and settlement structure. Hence, it does not take into account the functional ele- ments normally implied in the term regional struc- ture, e.g. dwellings, jobs and the aspects of infra- structure that support these. The concept has been used earlier for classification purposes by Räisänen et al. (1996) and Rusanen et al. (1997). We will first consider the situation over the whole of Finland and subsequently concentrate the anal- ysis on one specific region, Kainuu. The interpretation provided here is based on the assumption that the character of a grid cell can be deduced from the size of its population. The classification concerned is not necessarily appli- cable to all areas or to all countries, and it has been constructed knowing well that the distinc- tion between rural and urban is by no means un- ambiguous (see Malinen et al. 1994; Berry et al. 2000). It is impossible to build a model that would apply equally well to all countries and under all conditions. The following classification of spatial demographic structure is used: Inhab./km2 Element of spatial demographic structure 1–5 Scattered settlement 6–20 Rural areas proper 21–100 Rural areas with built-up features 101–1000 Build-up areas and suburbs with mostly private housing More than High-rise centres and suburbs of 1000 major cities Examination of the situation in the years men- tioned above indicates that the most densely pop- ulated areas, with over 1000 inhab./km2, grew most rapidly in the 1970’s, the rate of growth di- minishing in the 1980’s and reaching its slowest in the 1990’s (Fig. 1). The areas of suburban pri- vate housing departed from this pattern some- what, however, as these underwent their greatest population growth in the 1980’s. By contrast, the transitional category between rural and urban conditions, that with densities of 21–100 inhab./ km2, declined in population throughout the peri- od studied here, although most markedly in the 1970’s and least so in the 1990’s. The rural areas proper decreased substantially in extent, while the areas of scattered settlement increased somewhat in both total population and extent, largely as a result of contractions in the population of grid squares previously included in the category of ru- ral areas proper. The trend in population density over the whole country in the 1990’s was polarized. The popula- tion of the densely inhabited areas increased steadily throughout the decade, amounting to a total rise of 4.6%, or 110 000 persons, between 1990 and 1998 (Fig. 2). The suburban private housing population grew in a similar manner, with the exception of a small decline in 1997. The population of the urban-rural transition zone with densities of 21–100 inhab./km2, declined from 1993 onwards, however, and simultaneously the area contracted slightly. The category of rural ar- eas proper declined in both population and total area throughout the studied period, whereas scat- tered settlement category increased slightly in both total population and area. 136 FENNIA 181: 2 (2003)Jarmo Rusanen, Toivo Muilu, Alfred Colpaert and Arvo Naukkarinen Fig. 1. Population changes in different parts of the spatial demographic structure over the whole of Finland in 1970–1998 (Data: Statistics Finland). Fig. 2. Population changes in different parts of the spatial demographic structure over the whole of Finland in 1991–1998 (Data: Statistics Finland). The Kainuu region in Northern Finland, select- ed here for more detailed examination, is char- acterized by economic and demographic reces- sion. It belongs to the Objective 1 EU support ar- eas on account of its low income levels and sparse settlement. Its population, which has been on the decline since the 1960, was 93 218 per- sons in 1998, and the region has consistently been one with pivotal unemployment in the whole country. The demographic trend in Kainuu during the 1990’s departed markedly from that obtained for the whole country (Fig. 3). The most densely in- habited areas experienced a population decline from 1992 onwards, and the same trend affected the private housing areas from 1996 onwards. Correspondingly, the transition zone and the ru- ral areas proper lost population throughout the decade, as in the whole country, and the popula- tion increase in the areas of scattered settlement FENNIA 181: 2 (2003) 137Georeferenced data as a tool for monitoring the… appears to have come to an end in 1998. This was probably the first occasion during the century when the population of Kainuu decreased in eve- ry single category of its spatial structure. It is prob- able that demographic trends in the sparse popu- lation density classes in Fig. 9 were the same as in Kainuu. Elsewhere they have resembled those of the whole country. Finland became a member of the EU in 1995. Kainuu was an Objective 6 area in 1995–1999 and is currently an Objective 1 area for the peri- od 2000–2006. Based on the above results one can argue that the development measures imple- mented in the region under the EU programmes have failed to improve the negative demographic trend in all elements of the spatial system. Detailed analyses of population trends are pos- sible only with the aid of georeferenced data that allow precise location of the population units. A ‘sliding scale’ evaluation of population density based on local level data helps avoiding the fal- lacies that arise when one examines the whole country or large aggregate areas (Martin 1991). The unravelled negative demographic trend in Kainuu serves as an example of the use of grid cell data for monitoring regional development. The rank size model Rank size models represent a well-established method of geographical research that has been applied to the study of hierarchical structures in various areal units and changes taking place in these structures. The units employed for this pur- pose are usually towns or other administrative or functional entities (see, e.g. Bradford & Kent 1986; Das & Dutt 1993). The method involves arrang- ing the data units in size order and presenting the results in diagrammatic form. We intend to apply the rank size approach to the 1 x 1 km2 grid cells, and use the density classes for describing the types of settlement and any changes in popula- tion. For comparison purposes, the approach was done at two levels: the whole country and the Kainuu region. The 452 municipalities of Finland varied in population from a mere 100 up to 500 000 in- habitants in 1998 (Fig. 4). With the municipality level as the areal unit of interest, the rank size model indicates that about one hundred largest municipalities showed an increase in population over the period 1970–1998, while the others ex- perienced population decline. At the grid cell level, the rank size model fails to provide detailed information of spatial demo- graphic structure as efficiently the classification (Figs. 5 and 6). It does, however, serve well in highlighting the decline in the total number of in- habited grid cells over the whole country, i.e. the contraction in the area of human settlement. Fur- thermore, it emphasizes certain major turning points such as the beginning of the decline in population in the most densely inhabited areas Fig. 3. Population changes in different parts of the spatial demographic structure in Kainuu in 1991–1998 (Data: Statistics Finland). 138 FENNIA 181: 2 (2003)Jarmo Rusanen, Toivo Muilu, Alfred Colpaert and Arvo Naukkarinen Fig. 4. Changes in popula- tion density over the whole country in 1970–1998 ac- cording to the rank size model, areal unit = munici- pality (Data: Statistics Fin- land). Fig. 5. Changes in popula- tion density over the whole country in 1970–1998 ac- cording to the rank size model, areal unit = grid cell (Data: Statistics Finland). and the subsequent resumption of growth. Other well-presented features are the thinning of the population of the rural districts and the contin- ued growth in agglomerations with a population of 80–3000 persons throughout the studied peri- od. The points at which the curves intersect mark population thresholds of various kinds, with con- trasting trends on either side. The rank size model for the Kainuu region (Fig. 6) yields rather similar results to that for the whole country, the greatest difference being in the curve for 1998, which shows a decrease in pop- FENNIA 181: 2 (2003) 139Georeferenced data as a tool for monitoring the… ulation in the most densely inhabited grid squares as opposed to an increase at the national level. According to polls, the most preferred form of living for Finns is a detached house on lakeside in the middle of a city. The rank size model for the whole country indeed seems to indicate that apartment blocks in areas with more than 3000 inhab./km2 are not considered attractive as plac- es to live, since the model showed highest popu- lation growth in areas with population densities of 80–3000 inhab./km2. It is the grid cells that fall into this category that may be regarded as the most popular and attractive living environments in recent decades, a situation which has been pro- moted further by contemporary urban planning measures. This impression is confirmed by the re- sult of the Residents’ Barometer survey carried out by the Ministry of the Environment in 1998. The survey showed that 57% of Finnish population preferred to live in a private house, 22% in an apartment and 20% in a semi-detached or ter- raced house. In reality, only 30% of the popula- tion in that year were living in a private house, 50% in an apartment and 20% in a semi-detached or terraced house (Ministry of the Environment 2000). In the light of the above figures, however, the observed increase in population in the most densely inhabited areas during the 1990’s would appear to be inconsistent with the realities of the Finns’ living habits and with the preferences that they have expressed. The rank size approach also shows a decrease in population in the density class of less than 80 inhab./km2. This must be partly attributable to the decline in the number of active farms, a trend, which has greatly accelerated since Finland joined the EU in 1995. This becomes evident from the fact that no fewer than approximately one quarter of the farms closed down between 1995 and 2002. The rural areas can no longer provide good opportunities for making a living. As a con- sequence their population is declining. On the other hand, Silvasti (2002) has examined the changing meanings of the countryside for rural and urban inhabitants, noting that for farmers the countryside is traditionally a space in which pro- duction takes place, while for urban dwellers it is becoming more and more a locus of consump- tion, a source of recreation and beautiful land- scapes. In Holland, Haartsen et al. (2003) have developed an empirical method for measuring the interpretations placed on rural areas by persons of different ages (Muilu & Rusanen 2003). Fig. 6. Changes in popula- tion density in Kainuu in 1970–1998 according to the rank size model (Data: Statis- tics Finland). 140 FENNIA 181: 2 (2003)Jarmo Rusanen, Toivo Muilu, Alfred Colpaert and Arvo Naukkarinen Spatial distribution of population in 1970–1998 The most concrete, often the best and sometimes the only way of depicting spatial information is by means of a map, and a typical and popular way of depicting population data is on a chorop- leth map (see Bachi 1999). On the other hand, it is as well to bear in mind the comment of Lang- ford and Unwin (1994) that “Where the purpose of a population map is to convey an accurate im- pression of density distribution the conventional choropleth map representation is a poor choice”. The map of the distribution of inhabited areas presented in Fig. 7 is derived from a coloured map of Finland and Sweden first published by Rusanen et al. (1997), based on the kriging interpolation method (Figs. 8 and 9) and a choropleth map. The information depicted by shading has been con- verted to a dot-based vector form before interpo- lation. For the sake of comparison, the popula- tion density data are presented on a convention- al choropleth map in Fig. 10, employing munici- palities as the areal units. The pair of maps contained in Figs. 8 and 9 indicate detailed locations for the areas of pop- Fig. 7. Distribution of inhabited grid cells (at least one per- son per square kilometre) in Finland in 1998 (Data: Statis- tics Finland). Fig. 8. Population density (inhab./km2) in Finland in 1970 (Data: Statistics Finland). FENNIA 181: 2 (2003) 141Georeferenced data as a tool for monitoring the… ulation decline and serve particularly well to depict the pronounced expansion of the areas of scattered settlement. The extreme phenomenon that affects the settlement structure, namely the abandonment of the countryside, took place in Finland primarily in areas where habitation at present is sparsest. Future abandonment of dwellings and farms is likely to affect these same areas. On account of the scale at which the two maps are reproduced, the concentration of population in the built-up areas does not stand out very clear- ly. They do, however, highlight relatively well the population growth that has taken place in built- up areas and their environs, the areas in which population concentrated in 1998 and the loca- tions of municipal population centres. The information contained in this pair of maps highlights the situation regarding permanent set- tlement. It does not, however, tell the whole truth about the potential use being made of the areas concerned for leisure purposes. Some of the are- as of population decline, even ones that have lost their population entirely, have been transformed into a new kind of resource periphery, which peo- ple who have moved to the cities and urban are- Fig. 9. Population density (inhab./km2) in Finland in 1998 (Data: Statistics Finland). Fig. 10. Population density by municipalities in 1998 (Data: Statistics Finland) 142 FENNIA 181: 2 (2003)Jarmo Rusanen, Toivo Muilu, Alfred Colpaert and Arvo Naukkarinen as of the south have begun to exploit for summer cottages and second homes. Although the zonal maps in Figs. 8 and 9 are easy to interpret, the unfortunate aspect of them is that they give an impression of a wholly inhab- ited country. In contrast, the grid cell analysis in- dicates that in reality only 30.4% of its surface area had any permanent settlement in 1998 (Fig. 7) and that the focus of this settlement was explicitly in Southern Finland. The information contained in the zonal maps is nevertheless very detailed in comparison to the choropleth maps. Evaluation of the methods used Altogether 10 methods were tested in the course of the work at hand. Six methods involved numer- ical interpretation, four methods visual interpre- tation only. The rank size method yields diagrams, while the maps are descriptive in character. In terms of the hierarchy of potential areal units from the whole country to regions and further to mu- nicipalities, the grid cell is the most widely ap- plicable data unit. It permits aggregation to all spatial levels and can be used with all the meth- ods investigated. For reasons of scale, it is obvi- ous that a classification used for the whole coun- try will not necessarily be viable at the local lev- el. The same holds true for classifications used in cartographic presentations, as these, too, have to be altered according to the scale on which one is operating. The statistical mean, Gini Coefficient and Mo- ran and Geary Indices provided numerical proof of the continuing process of population concen- tration, hence confirming the conclusions. In the case of the Gini Coefficient, the employed areal unit influenced the results quite substantially. The data for the municipalities showed continuing concentration at a more pronounced level than did the grid cell data. Decile classification proved to be an objective method capable of demonstrat- ing changes in population density on a sliding scale from the sparsest to the densest forms of set- tlement. The spatial demographic structure proved the most adept at indicating what part of the spa- tial system is under examination – especially to those who are unfamiliar with the material. The last two classifications complement each other in the sense that the former is objective and the lat- ter subjective. The rank size model and the use of maps both allowed visualization of changes in population equally well over the whole country and at the local level. The methods can be regarded as complemen- tary in population concentration studies. It would be difficult and unnecessary to try to select the best method. Each method has its own strengths, and each one brings out some new information on changes in population density. A few recently published papers have pointed to a decline in the use of maps in geographical articles (Wheeler 1998; Martin 2000), which is somewhat surpris- ing, since GIS makes it relatively easy to present material in a map form. This trend may be regard- ed as an unfortunate one, since the present work and feedback received from the users of spatially analysed data indicate that maps, as a visual pres- entation technique, are the best means of describ- ing spatial variations in place-bound phenome- na. It is true, however, that one cannot visualize all the population changes taking place in a spa- tial structure by means of just a few maps. The other methods used here should be treat- ed as complementary to visualization and as ca- pable of lending support to each other. In the end it is essential that the available data be as accu- rate as possible in its location properties, so that GIS or potential other methods can be applied freely in accordance with the needs of different user groups. The optimum situation would natu- rally be the use of coordinate data for individual persons without any spatial aggregation. This, however, is depicted difficult or impossible by the legislation protecting personal privacy. Conclusions Demographic trends are crucial variables for use in regional policy, regional planning and moni- toring of regional development. Hence, the aim here was to investigate the distribution of popu- lation by a variety of methods. The results indi- cated that in Finland the process of population concentration in the early part of the 20th centu- ry, as identified by Alestalo (1983), continued up to the very end of the millennium. This finding is consistent with that obtained for Sweden, a coun- try with very similar conditions for settlement (Borgegård et al. 1995). One significant result of the analysis of the grid cell material, however, was that the concentration trend is now slowing down. This finding became evident also in terms of both the Gini Coefficient and the classification by spa- FENNIA 181: 2 (2003) 143Georeferenced data as a tool for monitoring the… tial demographic structure when the data units were grid cells, whereas more or less the oppo- site result was obtained when municipalities were used as areal units. In any case, the results do not correspond to the modest resurgence of popula- tion growth in non-metropolitan areas observed in the United States during the 20th century, a trend that can be regarded in the long term as rep- resenting a third decentralization phase (Long & Nucci 1997). According to the equilibrium theories of region- al economics, social structure will react to a dis- turbance by seeking a new state of equilibrium. In the light of its rates of change during the 20th century, the spatial demographic structure seems to be approaching such a state. At least the rate of population concentration has begun to slow down. The negative demographic trend obtained for the Kainuu region during the 1990’s neverthe- less demonstrates that various parts of the coun- try are progressing according to quite distinct timetables, not to mention the situation locally, i.e. at the level of the municipality or some small- er areal unit. The results from Kainuu are compa- rable to most parts of Finland, especially North- ern and Eastern and Central Finland, when the total land area is considered. In Finland the availability of annual population statistics for 1 x 1 km2 grid cells makes it possible to identify and monitor even quite small changes in different parts of the spatial structure, and thereby to quickly detect any violation of local or regional danger limits that are of importance for decision-makers and planners. It is also possi- ble to use grid cell data for predicting changes in population, whereupon the use of variables rep- resenting the age structure of the population or aspects of human activity are expected to add greater depth to such analyses. Finnish georefer- enced data can be subjected equally well to scru- tiny over medium or short time intervals, as in- formation is available from 1970 onwards and since 1987 on an annual basis. Grid cell data can provide information on lo- cal conditions and can be used to analyse differ- ences within municipalities. The ability to aggre- gate data to any grid size or areal system adds greatly to the applicability of the method. The per- manence of the location of the grid cells is also an important advantage, as administrative bound- aries tend to alter with time. Georeferenced data are flexible in terms of ar- eal unit, and are well suited to the analysis and visualization of features that are internal to given areas or regions. 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