Development of Integrated Spatial Analysis System Using Open Sources

Hisaji Ono

PASCO Corporation

1-1-2, Higashiyama, Meguro-ku, TOKYO, JAPAN; Telephone: +81 (03)3421 5846

FAX: +81 (03)3421 5846 Email: hi_ono2001@ybb.ne.jp

Yuji Murayama

Division of Geography, Institute of Geoscience, University of Tsukuba

Tsukuba, IBARAKI 305-8571, JAPAN; Telephone +81 (029) 853-4211

FAX +81 (029) 853-4211 Email mura@atm.geo.tsukuba.ac.jp

Abstract GeoComputation which attempts to integrate the quantitative geography and spatial visualization technology, has been very popular among GIS communities since the beginning of the 1990s. Especially the construction of platform for spatial analysis is one of the important research topics in the advanced countries. Luc Anselin who made SpaceStat, a spatial analysis software, has played a significant role in the development of GIS, and recently the Centre for Computational Geography at the University of Leeds, GeoVISTA Center at the University of Pennsylvania and Center for Spatially Integrated Social Science in the University of California, Santa Barbara have given a great impact on the development of spatial and regional analysis using GIS. Given this background, this study tries to construct the system of integrated spatial analysis which is useful for the GIS education for geography majors in the university. The functions of this system that was built by using only open sources, include the mapping, spatial search, TIN, overlay, point pattern analysis, spatial autocorrelation, multivariate analysis such as regression analysis, factor analysis and cluster analysis, neural network, tessellation, and so on. This system works at Windows98/Me/NT/2000/XP. This software is now available through the following Internet address(http://land.geo.tsukuba.ac.jp/teacher/murayama/geodbminer/index.html(Japanese)).

1. Introduction GeoComputation which attempts to integrate the quantitative geography and spatial visualization technology, has been very popular among GIS communities since the beginning

of the 1990s. Especially the construction of platform for spatial analysis is one of the important research topics in the advanced countries. Luc Anselin(1993) who made SpaceStat, a spatial analysis software, has played a significant role in the development of GIS, and recently the Centre for Computational Geography at the University of Leeds, GeoVISTA Center at the University of Pennsylvania and Center for Spatially Integrated Social Science in the University of California, Santa Barbara have given a great impact on the development of spatial and regional analysis using GIS. Given this background, this study tries to construct the system of integrated spatial analysis which is useful for the GIS education for geography majors in the university. The functions of this system that was built by using only open sources, include the mapping, spatial search, TIN, overlay, point pattern analysis, spatial autocorrelation, multivariate analysis such as regression analysis, factor analysis and cluster analysis, neural network, tessellation, and so on. This system works at Windows98/Me/NT/2000/XP. 2. System Integrated Spatial Analysis System’s architecture is showed in figure 1. This system’s GUI part was built by Java. As shown in Figure1, this system’s GIS engine employs GeoTools1 for Java with some modifications, abilities of spatial query and spatial analysis enabled and empowered by JTS, Java Topology Suite, API and regional analysis owes to R language with its contributed packages. And this system can process only ArcView shape file formats currently.

Figure 1..System Architecture of Integrated Spatial Analysis System.

Software required by Integrated Spatial Analysis System are listed in Table 1.

Table 1. Software required by Integrated Spatial Analysis System

Software Used Version Java2SE 1.4.1 or later R 1.7.0 or later R(D)COM 1.2

R contributed packages used by Integrated Spatial Analysis System are listed in Table 2.

Table 2. R contributed packages used by Integrated Spatial Analysis System

Package Function fields Kernel Density Estimation maptools Loading ArcView Shape files splancs Nearest Neighbourhood, K function spdep Spatial Autocorrelation tripack TIN, Voronois, convex hull

3. Functions 3.1 Choropleth Mapping

This system supports three types choropleth shading, equal length, quantile and Jenk’s natural breaks. And also supports circle dot mapping. 3.2 Gridding Creating grid surface. 3.3 Cartogram This system can create two types of area cartograms, continuous area cartogram(Figure 2) and non continuous area cartogram(Figure 3).

Figure 2. Continuous Area Cartogram

Figure 3. Non Continuous Area Cartogram

3.5 Surface This system can create grid surfaces.. 3.6 Query This system can issue spatial and aspatial queries against shape files.

1) spatial query Spatial query uses JTS API to perform following operators(Table 3).

Table 3. Operators of spatial query

Operator Function contains Select parts of target layer

contained by subject layer contained Select parts of subject layer

contained by target layer disjoint Select parts of target layer not

contained by subject layer equals Select parts of target layer equalled

to subject layer intersects Select parts of target layer

intersected subject layer overlaps Select parts of target layer

overlapped by subject layer touches Select parts of target layer touched

by subject layer within Select a part of target layer within

subject layer

An example of spatial query “touches” is showed in Figure 4.

Figure 4. Example of “touches”

2) aspatial query 3.7 Spatial Analysis This system can perform following spatial analyses using JTS API. And R’s contributed packages. 1) polygon overlay Operators of overlay are listed in Table 4 and polygon operators’ diagram is showed in Figure 5.

Table 4. Operators of polygon overlay

Operator Function intersection clipping target layer by subject layer difference difference between target and

subject layer symDifference symDifference between target and

subject layer union merge of target and subject layer

Figure 5. diagram of polygon overlay(VIVID SOLUTIONS(2002)) An example of polygon overlay is showed in Figure .6.

A.‚ ‰‚ Ž‚ ”‚ …‚ ’‚ “‚ …‚ ƒ‚ ”‚ ‰‚ •‚ Ž(B) A.union(B)

A.‚ „‚ ‰‚ †‚ †e‚ ’‚ …‚ Ž‚ ƒ‚ …(B) A.symDifference(B) B.‚ „‚ ‰‚ †‚ †e‚ ’‚ …‚ Ž‚ ƒ‚ …(A)

A

B

Figure 6.. Intersection’s example(Clipped town districts by 500m buffering of stations)

2) Buffering 3) Dissolve 4) TIN 5) voronois diagram 4) convex hull 3.8 Regional Analysis This system can deal with following methods. 1) descriptive statistics 2) multivariate analysis 3) ESDA 5) point pattern analysis 6) ANN(Artificial Neural Network) 3.9 Spatial Autocorrelation Using Byband’s spdep(2002), this system can cover almost methods of this area. This system can perform following analysis methods. 1) Global Moran’s I 2) Global Geary’s c 3) Local Moran 4) Local Geary 5) Join count 6) G & G* statistics Figure 7 shows output example of G* Statistics.

Figure 7 G* Statistics

4. Future Plans We have following plans for further developing this system. (1) Adding more analysis techniques. (2) Adding more visualisation functions. (3) Strengthening functions of saving results by analyses. (4) Fulfilment of printing function. (5).Database connection (6) Strengthening Internet connecting function (7) Scripting for automatic analysis (8) Internationalization (9) Web Applicationization. This software is now available through the following Internet address(http://land.geo.tsukuba.ac.jp/teacher/murayama/geodbminer/index.html (currently Japanese, but soon available in English). 5. References ANSELIN, L., 1993, SpaceStat: A Program for the Statistical Analysis of Spatial Data (Santa

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Modern Geography CATMOG), 59. GETIS, A., and ORD, J., K., 1992, The analysis of spatial association by use of distance

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issues and an application,. Geographical Analysis, 27, 286-296 VIVID SOLUTIONS, 2002, JTS technical specifications, http://www.vividsolutions.com/jts/jtshome.htm. .