Geospatial data conflation: a formal approach based on optimization and relational databases

ABSTRACT

Geospatial data conflation is aimed at matching counterpart features from two or more data sources in order to combine and better utilize information in the data. Due to the importance of conflation in spatial analysis, different approaches to the conflation problem have been proposed ranging from simple buffer-based methods to probability and optimization based models. In this paper, I propose a formal framework for conflation that integrates two powerful tools of geospatial computation: optimization and relational databases. I discuss the connection between the relational database theory and conflation, and demonstrate how the conflation process can be formulated and carried out in standard relational databases. I also propose a set of new optimization models that can be used inside relational databases to solve the conflation problem. The optimization models are based on the minimum cost circulation problem in operations research (also known as the network flow problem), which generalizes existing optimal conflation models that are primarily based on the assignment problem. Using comparable datasets, computational experiments show that the proposed conflation method is effective and outperforms existing optimal conflation models by a large margin. Given its generality, the new method may be applicable to other data types and conflation problems.     

Automatic extraction of road intersection points from USGS historical map series using deep convolutional neural networks

ABSTRACT

Road intersection data have been used across a range of geospatial analyses. However, many datasets dating from before the advent of GIS are only available as historical printed maps. To be analyzed by GIS software, they need to be scanned and transformed into a usable (vector-based) format. Because the number of scanned historical maps is voluminous, automated methods of digitization and transformation are needed. Frequently, these processes are based on computer vision algorithms. However, the key challenges to this are (1) the low conversion accuracy for low quality and visually complex maps, and (2) the selection of optimal parameters. In this paper, we used a region-based deep convolutional neural network-based framework (RCNN) for object detection, in order to automatically identify road intersections in historical maps of several cities in the United States of America. We found that the RCNN approach is more accurate than traditional computer vision algorithms for double-line cartographic representation of the roads, though its accuracy does not surpass all traditional methods used for single-line symbols. The results suggest that the number of errors in the outputs is sensitive to complexity and blurriness of the maps, and to the number of distinct red-green-blue (RGB) combinations within them.     

Mapping the Geographical Diffusion of a Finnish Smallpox Epidemic from Historical Population Records

Smallpox mortality from an early 19th century epidemic in Finland is mapped at the parish village level. First, geographically referenced historical materials are used to construct a map showing the spread of smallpox mortality among villages. Next, the diffusion of smallpox morbidity is simulated by computer for the same set of villages. These two maps are then compared. Results indicate that at this scale maps of mortality diffusion can show general trends but have no direct spatial correspondence to the underlying pattern of morbidity diffusion. Mortality maps cannot be used as a surrogate measure of infectious contact behavior at micro scales of analysis.     

Regional Geography and the Culture Area Construct—Western Europe: A Case Study

Abstract

The SYMAP program for producing line-printed maps on the computer is considered with respect to problems the new user is likely to have. Two groups of electives or options in the F-MAP package are discussed in detail: those that control map size and orientation and those that permit manipulation of the interpolation algorithm. Some classroom examples are suggested that emphasize the heuristic nature of the SYMAP program.     

The Educational Value of Geographical Exhibitions

Abstract

All maps lie, but some do so in especially interesting ways. Examples of errors or distortions can be found on maps appearing in magazines, newspapers, telephone directories, brochures, and even in geography textbooks. Special biases are often revealed in hand-drawn maps, or on written directions (virtual maps). Students can develop a critical eye by looking for, and collecting, maps that clearly, or cleverly, tell lies.     

A linear road object matching method for conflation based on optimization and logistic regression

The purpose of object matching in conflation is to identify corresponding objects in different data sets that represent the same real-world entity. This article presents an improved linear object matching approach, named the optimization and iterative logistic regression matching (OILRM) method, which combines the optimization model and logistic regression model to obtain a better matching result by detecting incorrect matches and missed matches that are included in the result obtained from the optimization (Opt) method for object matching in conflation. The implementation of the proposed OILRM method was demonstrated in a comprehensive case study of Shanghai, China. The experimental results showed the following. (1) The Opt method can determine most of the optimal one-to-one matching pairs under the condition of minimizing the total distance of all matching pairs without setting empirical thresholds. However, the matching accuracy and recall need to be further improved. (2) The proposed OILRM method can detect incorrect matches and missed matches and resolve the issues of one-to-many and many-to-many matching relationships with a higher matching recall. (3) In the case where the source data sets become more complicated, the matching accuracy and recall based on the proposed OILRM method are much better than those based on the Opt method.     

Demographic Transition: Threat to Developing Nations

Abstract

As computers become commonplace in the nation's schools, interactive maps are finding their way into the geography classroom. Students can use electronic atlases to access information as well as use authoring software to produce their own interactive maps. Does this change in media correspond to better geography education for our children? This article addresses whether using interactive maps for gathering and presenting information can have a positive influence on learning geography content. A two-week experiment was conducted in five 7th grade classrooms. Students in four of the classes researched and produced map products using both traditional and computer-assisted techniques. The fifth class was a control group. A pretest and two post-tests were given to quantitatively assess student learning after each project. Also, students were given a qualitative questionnaire to determine their attitude towards the different techniques. Quantitative results of the study indicate that there was no significant difference in student post-test performance after using each of the techniques, but qualitative results suggest that students prefer using the computer techniques over the traditional methods for gathering and presenting information.     

Comment on ‘Concerning “The economic evaluation of implementing a GIS‘”

Abstract

A fragmentation index has been implemented as a region based GIS operator to describe the spatial distribution of thematic classes in one data layer within map regions defined in another data layer. It has been applied to integrated analysis of digital maps and classified remote sensing data, for estimation of landscape complexity within watersheds and for detection of logged forest stands. The properties of the fragmentation index, when applied in this manner, are discussed. The fragmentation index is suggested as a valuable means of describing image characteristics of spectrally heterogeneous map regions.     

Using Road Maps in the Junior High School

Abstract

The activities described in this paper were developed to familiarize junior high school students with the variety of information available on road maps and to provide a means for practice of map skills. At Legg Junior High School in Coldwater, Michigan, students were presented with an introduction to road maps, followed by a series of worksheets to use in conjunction with Michigan and Ontario highway maps. After completing the worksheets, students participated in road rally games which required them to use maps and follow instructions and clues to find a specific location. The activities can be adapted for elementary school classes or for students with different levels of ability. Teachers might also want to increase the number of worksheets or road rallies to give students additional practice in skills in which they particularly need improvement.     

Ethnic Settlements on Topographic Maps

Abstract

The large scale topographic map can be a valuable medium for the pedagogic study of cultural geography, as a documentary source for research, or as a supplement to field work. Ethnic settlements, by way of illustration, are distinct cultural features on the landscape and can be located on topographic maps through the compilation of settlement form interpretation keys or place-name indexes, and the study of ethnic history. With this information as a base, it is possible to develop an interpretation logic that will allow the location and identification of ethnic groups on topographic maps.     

Modelling soil map-unit inclusions by Monte Carlo simulation

Abstract

Error and uncertainty in spatial databases have gained considerable attention in recent years. The concern is that, as in other computer applications and, indeed, all analyses, poor quality input data will yield even worse output. Various methods for analysis of uncertainty have been developed, but none has been shown to be directly applicable to an actual geographical information system application in the area of natural resources. In spatial data on natural resources in general, and in soils data in particular, a major cause of error is the inclusion of unmapped units within areas delineated on the map as uniform. In this paper, two alternative algorithms for simulating inclusions in categorical natural resource maps are detailed. Their usefulness is shown by a simplified Monte Carlo testing to evaluate the accuracy of agricultural land valuation using land use and the soil information. Using two test areas it is possible to show that errors of as much as 6 per cent may result in the process of land valuation, with simulated valuations both above and below the actual values. Thus, although an actual monetary cost of the error term is estimated here, it is not found to be large.     

A Review of “The Future Control of Food: A Guide to International Negotiations and Rules on Intellectual Property,Biodiversity and Food Security”

Abstract

Surface soil texture controls many important ecological, hydrological, and geomorphic processes in arid regions and is therefore important from a land-management perspective. Soil survey efforts have traditionally fulfilled this need, but they are constrained by the size, remoteness, and inaccessibility of many arid regions, which renders simple field measurements prohibitively expensive. This article compares several different predictive soil-mapping techniques with a sparse data set in order to develop surficial soil texture maps. Our results suggest that data collected at the landscape scale can be used as input to predictive soil-mapping techniques to create maps of soil texture at higher fidelity and a fraction of the cost than would be required using traditional methods.     

Comparisons of Conventional “Subdued” to Vivid “Highly Contrasting” Color Schemes for Elementary School Maps: Report of An Experiment

Abstract

The appropriateness of color schemes commonly used on maps for middle grade children has been inadequately researched. Most contemporary designs seem based more on adult conventions than on investigations to determine the factors that make maps interesting and readable to children. Based on four specially-prepared maps and 384 interview sessions with subjects enrolled in fourth, fifth, and sixth grades of a public school system, the findings of this study provide some clear implications for those who either design or purchase maps for classroom use.     

Green Costs,Red Ink: Determinants of Municipal Defensive Expenditures inOntario

Book reviews are in these Articles.

Understanding Peasant Agriculture: An Integrated Land-Use Model for the Punjab Joseph H. Astroth, Jr. Chicago: University of Chicago, Committee on Geographical Studies, 1990. (Geography Research Paper No. 223). ix and 173 pp., maps, photos, figs., apps., biblio., and index; $12.00 paper (ISBN 0-89065-127-2).

National Integration in Indonesia: Patterns and Policies Christine Drake. Honolulu: University of Hawaii Press, 1989. xvi and 354 pp., maps, diags., tables, index, and biblio. $35.00 cloth ISBN 0-8248- 1229-8).

Urban Economic Theory: Land Use and City Size. Masahisa Fujita. New York: Cambridge University Press, 1989. x and 366 pp., diag., graphs, biblio. notes, append, biblio., index. $65.00 cloth (ISBN 0-521-34662-2).

The Sugar Cane Industry: An Historical Geography from Its Origins to 1914. J. H. Galloway. Cambridge, MA: Cambridge University Press, 1989. xiii and 266 pp., maps, tables, diags., index, and biblio. $44.50 cloth (ISBN 0-521-24853-1).

Government Policy and Industrial Change. David Gibbs, ED. New York: Routledge, 1989. xvi and 317 pp., 15 figs., 53 tables, index, and biblio. $59.95 cloth (ISBN 0-415-01032-2).

English Agriculture: An Historical Perspective. David Grigg. New York: Basil Blackwell, 1989. vii and 256 pp. $60.00 cloth (ISBN 0-631-16033-7).

London 2001. Peter Hall. London: Unwin Hyman, 1989. xii and 226 pp., maps, diags., index, and biblio. $34.95 cloth (ISBN 0-04-4451 61 -X).

The Land that Became Israel: Studies in Historical Geography. Ruth Kark, ED. Translated from the Hebrew by Michael Gordon. Jerusalem: The Magnes Press, The Hebrew University and New Haven and London: Yale University Press, 1990. x and 332 pp., maps, diags., plates. $27.50 cloth (ISBN 0-300- 04718-5).

Die Farmer-Genossenschaften in den USA – Eine agrargeographie Untersuchung. Werner Klohn. Vechta, Federal Republic of Germany: Vechtaer Druckerei, 1990. Vechtaer Arbeiten zur Geographie und Regionalwissenschaft, Band 9. 285 pp., maps, photos, diags., and biblio. 39.80 DM paper (ISBN 3-88441-083-0).

Agricultural Development in Japan: The Land Improvement District in Concept and Practice. Gil Latz. Chicago, IL University of Chicago Press, 1989. vii and 135 pp., maps, diags., index, and biblio. $12.00 paper (ISBN 0-89065-129-9).

Land Use Planning Made Plain. Hok Lin Leung. Kingston, Ontario: Ronald P. Frye &; Company, 1989. xv and 237 pp., maps, diags., tables, append., index, and refs. $19.95 paper (ISBN 0-919741-98-3).

Computers in Geography. David J. Maguire. New York: Halsted Press, 1989. xv and 248 pp., maps, photos, diags., index, and biblio. $31.95 paper (ISBN 0-470-21 194-6).

Maps with the News: The Development of American Journalistic Cartography. Mark Monmonier. Chicago: The University of Chicago Press, 1989. xii and 331 pp., maps, illus., index, and biblio. $24.95 cloth (ISBN 0-226-53411-1).

Geographic Information Systems and Cartographic Modeling. C. Dana Tomlin. Englewood Cliffs, NJ: Prentice Hall, 1990. xviii and 249 pp., maps, diags., review questions, selected readings, appendix, index, $44.20 cloth (ISBN 0-13-350927-3).     

Error propagation in cartographic modelling using Boolean logic and continuous classification

Abstract

When data on environmental attributes such as those of soil or groundwater are manipulated by logical cartographic modelling, the results are usually assumed to be exact. However, in reality the results will be in error because the values of input attributes cannot be determined exactly. This paper analyses how errors in such values propagate through Boolean and continuous modelling, involving the intersection of several maps. The error analysis is carried out using Monte Carlo methods on data interpolated by block kriging to a regular grid which yields predictions and prediction error standard deviations of attribute values for each pixel. The theory is illustrated by a case study concerning the selection of areas of medium textured, non-saline soil at an experimental farm in Alberta, Canada. The results suggest that Boolean methods of sieve mapping are much more prone to error propagation than the more robust continuous equivalents. More study of the effects of errors and of the choice of attribute classes and of class parameters on error propagation is recommended.     

SCALING TECHNIQUES IN THE ANALYSIS OF ENVIRONMENTAL COGNITION DATA∗

The utility of nonmetric, multidimensional-scaling techniques is demonstrated for the analysis and collection of environmental-cognition data. By comparing the multidimensional-scaling solutions of a real-setting map to scaling solutions for sketch maps and two psychophysical, distance-scaling procedures, we demonstrate that magnitude estimation of actual interpoint distances is comparable in accuracy to sketch maps when produced without constraints, or when subjects are given a specified list of landmarks to include on their maps. Triadic comparisons of actual interpoint distances were less accurate than the three other techniques.     

Going beyond location: Thematic maps in the early elementary grades

Abstract

Cartographic research has long suggested that preschool and early elementary children possess advanced mapping behaviors in terms of interpreting, making, and using locational and wayfinding maps. To improve instruction in geographic concepts, it is necessary to see if these advanced mapping behaviors apply to thematic or special purpose maps as well, as an understanding of these types of maps is integral to the five fundamental themes of geography. An experiment was conducted to evaluate the thematic mapping abilities of second-grade students. Students viewed maps at the neighborhood, city, and national scales displaying different types of symbolization and presented in a random order. Results indicated that the map tasks were appropriate for this age level, and a statistical test of reaction times did not identify a best symbol type or scale, as all were appropriate for this age level. Responses to discussion questions indicated the students also have the ability to describe spatial patterns. The interpretation of quantitative information on maps is within the ability level of second grade students, and materials currently used in second grade should be revised to include these maps.     

A Project Study of Climate

Abstract

Atlas of American Women by Barbara Gimla Shortridge New York: Macmillan, 1987. xi and 164 pp., figs., tables, maps, biblio., and index. $85.00 cloth.

The Geography of Defence by Michael Bateman and Raymond Riley, eds. Totowa, NJ: Barnes &; Noble, 1987. xi and 237 pp., figs., tables, photos, maps, refs., and index. $33.50 cloth.

Zones of Conflict: An Atlas of Future Wars by John Keegan and Andrew Wheatcroft New York: Simon &; Schuster, 1986. xvii, 158 pp., and maps. $10.95 paper.

From Peasant to Farmers: The Migration from Balestrand, Norway to the Upper Middle Wets by Jon Gjerde Interdisciplinary Perspectives on Modern History Series, eds. R. Fogel and S. Thernstrom. New York: Cambridge University Press, 1985. xiv and 319 pp., illus., figs., tables, photos, maps, refs., and index. $32.50 cloth.

Power and Place: Canadian Urban Development in the North American Context by Gilbert A. Stelter and Alan F.J. Artibise, eds. Vancouver: University of British Columbia Press, 1986. iv and 398 pp., figs., tables, photos, maps, and refs. $24.50     

Notes

Abstract

The concept of correlation is becoming increasingly important to students of all ages as the use of electronic data base technology becomes more common. Data maps offer a significant and new format for secondary students to use along with tables of values and scatter plots as they learn and apply the correlation concept. Data maps are particularly effective in promoting the interdisciplinary treatment of important content by allowing students to interpret social or physical relationships within the geographic context in which they arise.