An efficient algorithm was developed for generating horizons for each point in a digital elevaton grid in order N iterations. In two dimensional case, however, the algorithm has been suffered from the ambiguity in the definition of horizons. In this paper, we prove some important theorems based on a formal definition of the horizon which is applicable to two dimensional situation. For actual calculation, rotation and interpolation of the DEM are considered. We adopt a parametric cubic convolution familly of functions for the interpolation, which can control smoothness and sharpness of the converted DEM. The sampling interval is analyzed with regard not only to computational efficiency but also to estimation error.

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The vegetation in the suburban forests-usually called as "Satoyama"-is rich and complex. However, the detailed data of the topography for geographical analysis could not be gotten. We could make the detailed topographical data (5m grid DEM) from the aerial photographs taken in 1995, and also restore the vegetations (divided for 9 categories) from the aerial photographs in 1949, 1977 and 1995 over about 6.1km2 in a part of the suburban forest, Kaisho & Hirokute Forest, near Nagoya City, central part of Japan. Interannual change of the vegetation and its considerable reasons could thus be analyzed from the topographical environment. We can get only 323 patterns of the vegetation category change through 3 terms. The 13 main patterns (explained for 47.5% of all) of the category change are selected and almost of these patterns are arrived at category-C (delicious forest). It is suggested that the change patterns have some relationship to the altitude, slope angle and slope direction.

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The fast evolving information space forms a new arena for geographical analysis which enhances our understanding of the structure of digital spaces, thus potentially affecting the urban lives and socio-economic activities that have become increasingly dependent on information technology. Assuming that the information space forms a quantitatively measurable entity and should be addressed in the geographical context, this study combines spatial analysis techniques with GIS technologies to explore the structure of the World Wide Web in terms of its node connectivity. We investigate the number of homepages and the reciprocal hyperlinks between 180 global Internet domains and determine the location that is central to the information space. The hyperlink structure is treated as a network and a virtual distance between these domains is calculated from which the mini-sum distance of all the sites is determined. The results are overlaid onto an atlas to help to understand the relationship between the information space and the existing geographical space.

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A geospatial Data Clearinghouse is a system to provide information about a geospatial data. The aim of this systemis to promote to share geospatial data among users and researchers effectively. In this paper, we focus on the architecture of clearinghouse. First, we categorize some architecture in point of management type of some clearing node. Second, we propose Node Information eXchanger (NIX) to realize effective information retrieval under the distributed network. Some experimental results show some advantages of our proposed system.

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This paper is the fourth part of a series of reports that proposes methods to estimate precision of spatial information. This part compares two methods. One (method 1), based on a theoritical model concerning length of segments on spatial information, is proposed in the second part of the report. The other (method 2), comparing positions of one point between different kinds of spatial information, is proposed in the third part. The result shows that method 1 is more effective when precision may be small and robust against systematic errors but expensive. On the other hand, method 2 is effective when precision may be large and inexpensive but sensitive to systematic error.

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This paper proposes a method to evaluate accuracy of horizontal position on spatial information. First of all, we introduce an assumption that errors of positions on GIS data obey two dimensional normal distribution (T.D.N.D.). Then the paper shows that a vector obeys T. D. N. D., if both ends obey T.D.N.D. independently. It also shows the method estimating accuracy by comparing positions of the same point on different kinds of spatial information. Finally, a case study of pictures by SPOT satellite is done using the method.

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This paper presents a spatial data transfer system to adapt to large-scale distributed networks and to improve data transfer performance with caching technique and concurrent reading process. We design this system using UML based on object-oriented analysis. We show some advantages in our proposed system against the ordinary GIS, in special, suitability to distributed networks.

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This article purposes to evaluate the influence of the road potential on the transition of land use. The key concept of the analysis is the "potential contour", which is a kind of contour connecting the same level of the potential with respect to road width. Before producing the contour, point sampling data of road width is transformed into the "softened" point mesh data through a kind of smoothing process. These methods enable to evaluate the potential of the area which cannot be defined by ordinary methods such as buffering. The result of the analysis shows the existence of the threshold for the transition trend of urban land uses.

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An automated animal location system based on the Global Positioning System (GPS-col-lar) was attached to a female Sika deer (Cervus nippon) for wildlife research in early March of 2000 on Kinkazan Island, northern Japan. We successfully recovered the GPS-collar in late April and downloaded the data. We evaluated inherent properties of the GPS-collar data and effects of move-ments and habitat selection on the GPS-collar's performance; we then compared the GPS-based tracking system with a radiotelemetry system. The GPS-collar is a potentially promising tool for wildlife tracking studies in terms of its positional accuracy, arbitrary sampling intervals, low cost and integrated analysis with GIS-data

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This paper focuses on two types of sports clubs located in Fukuoka City and analyzed their service areas using GIS. The service area of each type of club was compared with that of three sports clubs located in Kagoshima City. The results of the analyses in this study are summarized as follows:
1) About 90% of the members are included within circles of 4km and 6km defined around "Next to Residential area" and "Terminal" types of sports clubs respectively. 2) For the type of "Terminal" sports club, intermediate level of service area was expanded to the districts along subway and rail-way. 3) Market penetration ratio for "Next to Residential area" type had fallen more sharply than for "Terminal" type with the increase of distance from the club. 4) As the result of comparing with the clubs in Kagoshima city, these two sports clubs in Fukuoka city were classified as the concentrated type in terms of the inner structure of service areas.

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The aim of this paper is to observe the influence of geographical and historical characteristics, such as culture-assets, in the enactment of townscape ordinance. Geographical data are extracted using GIS and incorporated with author's researched data of townscape ordinance. Detailed analysis is undertaken by correlation analysis. High correlation coefficients are obtained for penal regulation in prefectural townscape ordinaces, which underlines the awareness of cultureassets. Relatively low correlation coefficients are obtained for autonomy townscape ordinance Measures, which underlines the lack of understanding of the importance of culture-assets. Higher correlation coefficients are obtained by categorizing the culture-assets into smaller groups for correlation analysis, which underlines the need of detailed geographical data for further analysis.

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With the recent expansion of Geographical Information System (GIS) related projects in governmental investments for promoting regional information society, the role of GIS must be considered. In this paper, we examine nine examples of GIS developed by local governments and classify the examples into four types from the standpoint of the role of GIS: 1) wide-area administrative information system, 2) regional vitalization, 3) information disclosure, and 4) interactive residentslocal government relationship. By analyzing these four types, we clarify current and future problems of using GIS for regional information society.

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This is a comparative study on the utilization of Geographic Information System (GIS) in local governments between Japan and Korea. Two questionnaires are used for the analysis that were collected from local governments of the two countries by questionnaires in 1999. In result, (1) The percentage of running GIS shows nearly same ratio in both regional and base local government respectively of the two countries. (2) Large population cities group have larger ratio of running level of GIS than small cities. (3) The major common problems of GIS in two countries are insufficient finance, data and system sharing, the lack of knowledge and technique on GIS.

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This paper discusses technical problems in constructing choropleth maps based on the various classification methods by GIS. Especially, it tries to consider how different classification methods affect spatial pattern of data represented on the choropleth maps. Area of floor space per persons and population density of 85 municipalities in Chiba prefecture are used as the data, which are obtained from 1995 Population Census of Japan. While area of floor space per persons is selected as an example of continuous data, population density is an example of discontinuous data. The following five classification methods are applied to the data: standard deviation, equal interval, quartile, equal area, and optimal methods. As the result, it becomes clear that optimal method is able to classify continuous and discontinuous data adequately. On the other hand, standard deviation method is suitable for the classification of continuous data, but is unsuitable for discontinuous data. Equal interval methods are unsuitable for continuous and agglomerated data and discontinuous data.

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