System Design Considerations for the Development of an Electronic Statistical Atlas

In the recent history of cartography, atlases deserve a prominent status among cartographic products due to the variety of their thematic content, the rather friendly appearance and their utilization by a wide spectrum of users. Advances in information technology, and more specifically in geographic information systems and digital mapping, have altered the fundamental way of using maps, and thus they have a major impact on every aspect of electronic atlas design and development. Although considerable effort has been made towards the production of electronic atlases, and successful systems are available, there are still a number of factors that must be considered towards the improvement of their design and functional characteristics. This paper elaborates on those factors and suggests a specific approach toward the design and development of electronic atlases, particularly electronic statistical atlases. This approach has been used for the development of the Statistical Atlas of the European Union (STATLAS_EU), which is intended to provide a user-friendly resource for statistical analysis.     

Probabilistic mapping of flood-induced backscatter changes in SAR time series

The information content of flood extent maps can be increased considerably by including information on the uncertainty of the flood area delineation. This additional information can be of benefit in flood forecasting and monitoring. Furthermore, flood probability maps can be converted to binary maps showing flooded and non-flooded areas by applying a threshold probability value p_F = 0.5. In this study, a probabilistic change detection approach for flood mapping based on synthetic aperture radar (SAR) time series is proposed. For this purpose, conditional probability density functions (PDFs) for land and open water surfaces were estimated from ENVISAT ASAR Wide Swath (WS) time series containing >600 images using a reference mask of permanent water bodies. A pixel-wise harmonic model was used to account for seasonality in backscatter from land areas caused by soil moisture and vegetation dynamics. The approach was evaluated for a large-scale flood event along the River Severn, United Kingdom. The retrieved flood probability maps were compared to a reference flood mask derived from high-resolution aerial imagery by means of reliability diagrams. The obtained performance measures indicate both high reliability and confidence although there was a slight under-estimation of the flood extent, which may in part be attributed to topographically induced radar shadows along the edges of the floodplain. Furthermore, the results highlight the importance of local incidence angle for the separability between flooded and non-flooded areas as specular reflection properties of open water surfaces increase with a more oblique viewing geometry.     

Light mode and dark mode: Which one is suitable when using public-facing web maps? An experimental evaluation using eye-tracking

Dark maps, which are also called dark modes or dark themes, have gained popularity, but their usability has not been experimentally evaluated. This article presents a user experiment that uses eye-tracking to assess the usability of dark and light maps. Here, two widely used web maps, Google Maps and Gaode Maps, are selected at the street and city scales. Eight map-use tasks are designed and cover four operations (identify, compare, rank, and associate) with space-alone and attributes-in-space distinctions. Four pairs of map-use tasks (light-during-the-day, dark-during-the-day, dark-at-night, and light-at-night) are examined from three aspects: effectiveness, efficiency, and cognitive load. The results provide preliminary evidence that the light-during-the-day performance is generally the best in most cases, followed by the dark-at-night performance; the dark-during-the-day performance is the worst in all cases, followed by the light-at-night performance, which suggests that aligning the map design with the environment (i.e., lighting environment) is critical for better communication. The light-during-the-day performance is the best for space-alone tasks, and the dark-at-night performance is the best for attributes-in-space tasks. Our investigation also indicates that dark maps are far less favored in practice, which suggests that users' preference for using the dark mode of public-facing web maps needs to be shaped. Since light and dark maps are associated with photopic and scotopic vision, respectively, the results indicate the need for future studies on how to leverage scotopic vision to design better dark maps.     

CHARACTERISTICS OF A DATA PROCESSING TECHNOLOGY FOR THE REVISION OF DIGITAL MAPS

A procedure is described for the revision of digital maps in geographic information systems, the basis of which rests upon a “mutual and unambiguous correspondence” between a digital map and its structural (text or graphic) model(s). Rules of transference, editing, elimination, inclusion, and cross-referencing of names are elaborated for regulation of the processes by which non-digital (cartographic, air photo, statistical) sources of new information are used to transform digital information in the original data base. Revision of digital maps is accomplished through creation of a data base of digital corrections to an original data base and/or subsequent editing of digital map(s) from these corrections or others initiated during raster scanning. Translated from: Geodeziya i kartografiya, 1986, No. 9, pp. 38-43.     

Monitoring the decrease of lake Chad from space

Observations from space of the open water areas within Lake Chad are presented. They complement andsustain the earlier study of Mohler et al. (1989), which demonstrates a decrease of about 90 percent in surface between 1966 and 1986. Further, Meteosat images were processed to obtain weekly maps of albedo following the scheme of Mousssu et al. (1989). The analysis of these maps throughout the year reveals the functioning of the lake as well as the large variability of the open water areas during a year.     

SYSTEMS MAPPING OF THE PHYSICAL-GEOGRAPHIC PROCESS IN A MARINE ENVIRONMENT

An analog to the (terrestrial) physical-geographical process, the concept of boundary surfaces, is elaborated and developed quantitatively for analyzing the diversity of marine ecosystems. Interactions among physical-chemical components of the oceans, and the adjacent coastal, atmospheric, and ocean bottom environments, provides a model used in the study and mapping of heterogeneous “waterscapes.” A series of tables identifies interacting geographic features commonly used as indices for mapping. Sample maps prepared for the Barents Sea and Indian Ocean demonstrate possible results of a systems approach. Translated from: Izvestiya, Vsesoyuznogo geograficheskogo obshchestva, 1985, No. 3, pp. 201-208.     

Opening the London Underground to visually handicapped tourists

Abstract

There are several practical rules for determining categories (class intervals) for maps representing statistical data, like arithmetic, geometric or equal steps etc. In this paper, however a coherent method is proposed to provide statistically separable Classes on a map with minimum redundancy in terms of information content.

The number of class intervals can be directly computed by means of appropriate statistical methods if the widths of classes are determined by t-test, i.e. when their difference is significant at a high level of confidence. A class narrower than this width would represent data in different categories due only to variance, however, the selection of wider classes leads to a certain loss of information.

The class intervals determined this way should be positioned on the statistical data-set so that each category contains approximately equal number of data providing maximum information content of the output map. At the final step the class intervals derived this way should be rounded, if necessary, to provide user-friendly maps.     

Using computational intelligence techniques to model subglacial water systems

Measurements of water pressure beneath Trapridge Glacier, Yukon Territory, Canada show that the basal water system is highly heterogeneous. Three types of behaviour were recorded: pressure records which are strongly correlated, records which are strongly anticorrelated, and records which alternate between strong correlation and strong anticorrelation. We take the pressure in bore-holes that are connected to the evacuation route for basal water as the forcing, and the other pressures as the response to this forcing. Previous work (Murray and Clarke 1995) has shown that these relationships can be modelled using low-order nonlinear differential equations optimized by inversion. However, despite optimizing the model parameters we cannot be sure that the final model forms are themselves optimal. Computational intelligence techniques provide alternative methods for fitting models and are robust to missing or noisy data, applicable to non-smooth models, and attempt to derive optimal model forms as well as optimal model parameters. Four computational intelligence techniques have been used and the results compared with the more conventional mathematical model. These methods were genetic programming, artificial neural networks, fuzzy logic and self-organizing maps. We compare each technique and offer an evaluation of their suitability for modelling the pressure data. The evaluation criteria are threefold: (1) goodness of fit and an ability to predict subsequent data under different surface weather conditions; (2) interpretability, and the extent and significance of any new insights offered into the physics of the glacier; (3) computation time. The results suggest that the suitability of the computational intelligence techniques to model these data increases with the complexity of the system to be modelled.     

THE ACCURACY OF VISUAL DETERMINATIONS OF STATISTICAL CHARACTERISTICS FROM MAPS

The authors address a range of issues connected with the visual representation and interpretation of statistical data on maps. Attention is focused on common behaviors of map users in determinations of various characteristics of map symbols. Results are reported from experiments testing the relationship between the accuracy of obtaining quantitative information on a map with the total number of symbols and number of scale levels [size classes] employed, the use (or non-use) of color in the symbolization scheme, etc. Translated by Larry Richardson, Los Angeles, CA 90039 from: Izvestiya Vsesoyuznogo Geograficheskogo Obshchestva, 1989, No. 4, pp. 345–351.     

结合先验概率估计的GF-3影像水体概率估计方法

综合SAR(synthetic aperture radar)影像的统计模型假设与k-means聚类算法,提出了一种结合水体分布先验概率估计的水体概率估计方法。首先,用贝叶斯推断对研究区域后向散射系数做统计模型假设。随后,结合聚类算法对像元作分类,估计水体分布先验概率,结合统计分布直方图使用非线性最小二乘拟合完成模型参数估计。试验选取了高分三号(GF-3)多种工作模式数据,并用高分一号(GF-1)影像进行验证。结果表明,该方法可有效实现SAR影像的高精度水体概率估计。     

THE CLASSIFICATION AND MAPPING OF IMPRECISE GEOGRAPHIC SYSTEMS

The author describes problems with traditional statistical and cartographic methods employed in the classification and mapping of ambiguously or vaguely defined features. Using a series of maps on the same subject (the foreign trade relations of European countries and the USSR), he demonstrates that greater attention should be paid to potential changes in the distribution of mapped objects depending on the criteria selected and the classification algorithms employed, argues that multiple classification strategies be used to determine optimal strategies for visually representing imprecise systems, and provides recommendations for their graphic representation. Translated by Kurt E. Engelmann, University of Washington, Seattle, WA 98195 from: Vestnik Moskovskogo Universiteta, geografiya, 1989, No. 3, pp. 16–23.     

Least squares collocation and statistical testing

The authors address the issue of statistical testing in least squares collocation (LSC) in two stages. The first stage concerns the extension and focusing of theLSC equations to the task of statistical testing. The second stage deals with statistical testing titself and is introduced in the second portion of the paper. The paper commences with an overview of the development ofLSC and its relationship to least squares adjustment (LSA). Expressions for the various random variables and their corresponding covariance matrices are derived and in some instances are gleaned from the literature for the following quantities: (i) corrections to the unknown parameters with a priori covariance information; (ii) estimated signal at both the observation and computation points; and (iii) the noise at the observation points. Some of the needed covariance matrices are either obscurely hidden in the literature or not available at all, but, nevertheless are given in the paper. Also given are expressions for the estimated variance factor which forms the basis of various statistical tests. The paper closes with an overview and enumeration of possible statistical tests for detection of outliers in the observations.     

Remote sensing and geoinformation center of Mongolia: A brief outlook

Abstract

A GIS based approach is proposed for the integration of three thematic maps viz. geomorphology, drainage density and slope using fuzzy logic for the assessment of ground water resource potential of a soft rock terrain of Midnapur District, West Bengal, India. The geomorphology and drainage density maps of the area are prepared from IRS‐1B LISS‐II data, and the slope map is obtained from the contours depicted on the topographic map of Survey of India. Each feature of all the thematic maps is assigned with individual fuzzy set values within a range between 0 to 1 according to their relative importance in the prediction of ground water occurrence. The maps are then integrated through fuzzy operation to model the ground water potential zone of the study area. The evolved model while verified with surface geophysical results is found to be in good agreement.     

Modelling relational contexts in GEOBIA framework for improving urban land-cover mapping

In human cognition, both visual features (i.e., spectrum, geometry and texture) and relational contexts (i.e. spatial relations) are used to interpret very-high-resolution (VHR) images. However, most existing classification methods only consider visual features, thus classification performances are susceptible to the confusion of visual features and the complexity of geographic objects in VHR images. On the contrary, relational contexts between geographic objects are some kinds of spatial knowledge, thus they can help to correct initial classification errors in a classification post-processing. This study presents the models for formalizing relational contexts, including relative relations (like alongness, betweeness, among, and surrounding), direction relation (azimuth) and their combination. The formalized relational contexts were further used to define locally contextual regions to identify those objects that should be reclassified in a post-classification process and to improve the results of an initial classification. The experimental results demonstrate that the relational contexts can significantly improve the accuracies of buildings, water, trees, roads, other surfaces and shadows. The relational contexts as well as their combinations can be regarded as a contribution to post-processing classification techniques in GEOBIA framework, and help to recognize image objects that cannot be distinguished in an initial classification.     

Specialist Maps of the Channel Islands Prepared by German Military Geologists during the Second World War: German Expertise Deployed on British Terrain

Abstract

During the German occupation of the Channel Islands, military geologists produced specialist maps to support their development as part of the Atlantic Wall: the line of fortifications marking the western boundary of German-occupied Europe. For Jersey, maps showed features of groundwater and quarry sites for building materials, primarily at a scale of 1 : 25 000. For Guernsey, maps at this scale were prepared to depict bedrock and superficial geology, and also maps which showed sites for building materials, water supply and features of military geology. For Alderney, maps at 1 : 10 000 showed bedrock geology, water supply, building materials plus tunnelling conditions, and military geology. Only a few contemporary copies of these maps were produced, hand-drawn upon printed topographical base-maps. Some are now preserved in Germany at the Bundesarchiv-Militärarchiv, others in the USA at the National Archives and Records Administration. They include the only military geology maps, the earliest large-scale groundwater maps and arguably the earliest large-scale building resources maps, for any part of the British Isles.     

In-depth examination of spatiotemporal figures in open reproducible research

ABSTRACT

Figures such as maps and time series are essential means to visualize spatiotemporal results in scientific papers. Being able to recompute them using the underlying source code and data is thus a core aspect in reproducible research. However, many scientists see the preparation of code and data for publication as an additional burden without immediate benefits. In this work, we investigate advantages and new capabilities of reproducible research papers. Our key contributions are (i) the extension of a geoscientist’s workflow while examining papers including reproducible figures such as maps and (ii) the prototypical implementation of the workflow as a web application. The workflow is based on current practices of geoscientists and encapsulates benefits of reproducible figures. It is informed by ideas and needs identified by geoscientists in a survey, interviews, and a focus group. Based on their statements, we first extend the traditional workflow steps Discovery and Inspection by additional capabilities and propose two new steps: Manipulation of the content of a spatiotemporal figure and Substitution of the underlying code and data. The extended workflow and its implementation might facilitate in-depth examination and reusability of geoscientific results.     

ECOLOGICAL-GEOGRAPHIC MAPPING: CONCEPTS,METHODS, AND TECHNOLOGY

Another paper in a series of articles on ecological-geographic mapping (see for example, Mapping Sciences and Remote Sensing, Vol. 31, No. 3, July-September 1994, pp. 185-220) focuses on outlining a concise typology of such maps and providing a brief history of their emergence during the 1970s and 1980s. A subsequent section is devoted to methods and technology used in the compilation of ecological-geographic maps, particularly the multiple variants of data organization, processing, and cartographic representation that can be factored into research design. Translated by Edward Torrey, Alexandria, VA 22308 from: Geografiya i prirodnyye resursy, 1995, No. 4, pp. 10-18.     

Frequency Histogram Legend in the Choropleth Map: A Substitute to Traditional Legends

This article presents the use of the frequency histogram legend (FHL) as a substitute to traditional legends in both classed and unclassed choropleth maps. Great variation in the size of mapping units can hinder readers' ability to comprehend statistical distributions from a choropleth map. Replacing conventional legends with FHL can aid readers in their understanding of spatial as well as statistical distributions of the mapped data simultaneously. A customized mapping application was designed in ArcInfo 9.0 to test the use of FHL in both classed and unclassed choropleth maps. Frequency histogram legends were tested on different types of statistical distributions. Although the comparison of the results shows that the FHL works best for a Gaussian or close to a Gaussian distribution for eight or fewer classes, the customized application permits users to generate choropleth maps with frequency histogram legends for any type of statistical distribution with any number of classes. The analysis reveals that readers' background in statistics helped them to effectively utilize and interpret frequency histogram legends in the choropleth maps.     

Downscaling Landsat-8 land surface temperature maps in diverse urban landscapes using multivariate adaptive regression splines and very high resolution auxiliary data

ABSTRACT

We propose a method for spatial downscaling of Landsat 8-derived LST maps from 100(30?m) resolution down to 2–4?m with the use of the Multiple Adaptive Regression Splines (MARS) models coupled with very high resolution auxiliary data derived from hyperspectral aerial imagery and large-scale topographic maps. We applied the method to four Landsat 8 scenes, two collected in summer and two in winter, for three British towns collectively representing a variety of urban form. We used several spectral indices as well as fractional coverage of water and paved surfaces as LST predictors, and applied a novel method for the correction of temporal mismatch between spectral indices derived from aerial and satellite imagery captured at different dates, allowing for the application of the downscaling method for multiple dates without the need for repeating the aerial survey. Our results suggest that the method performed well for the summer dates, achieving RMSE of 1.40–1.83?K prior to and 0.76–1.21?K after correction for residuals. We conclude that the MARS models, by addressing the non-linear relationship of LST at coarse and fine spatial resolutions, can be successfully applied to produce high resolution LST maps suitable for studies of urban thermal environment at local scales.     

Water Supply Maps for the Western Front (Belgium and Northern France) Developed by British,German and American Military Geologists during World War I: Pioneering Studies in Hydrogeology from Trench Warfare

Abstract

Innovations for the British Army during World War I included use of a military geologist to compile 'water supply' maps and to guide well drilling. Between June 1915 and November 1918, W. B. R. King served as a staff lieutenant at General Headquarters of the British Expeditionary Force deployed on the Western Front. He pioneered British development of water supply maps for parts of Belgium and northern France, in several different styles and at scales of 1 : 100 000, 1 : 250 000 and 1 : 40 000. These assisted planning for advances into enemy-occupied territory or the development of water supply infrastructure within the region held ultimately by five British armies: in total about 1,500,000 men with some 500,000 horses and mules, each man/animal requiring on average 10 gallons (45 L) per day of potable water. The maps guided emplacement of over 470 military boreholes to supply drinking water to British forces, especially in provinces underlain by Cretaceous Chalk: Picardy and Artois. German forces also made use of military geologists at the Front, but in much greater number: up to about 300 in total. Water supply tasks were given high priority, and German water supply maps were finally standardized like other medium scale German geotechnical maps at 1 : 25 000. Six geologists were deployed with the American Expeditionary Force late in the war, and for their sector of the Front compiled at least two water supply maps at 1 : 80 000, and 11 at 1 : 50 000 that were supported by explanatory reports. Wartime imperatives thus generated expertise in hydrogeology that became available for civilian use post-war, and laid the foundation for further military development during World War II.