Landcover Classification in the Taieri River Catchment,New Zealand: A Focus on the Riparian Zone

Abstract

Riparian vegetation has a fundamental influence on the biological, chemical and physical nature of rivers. The quantification of riparian landcover is now recognised as being essential to the holistic study of the ecosystem characteristics of rivers. Medium resolution satellite imagery is now commonly used as an efficient and cost effective method for mapping vegetation cover; however such data often lack the resolution to provide accurate information about vegetation cover within riparian corridors. To assess this, we measure the accuracy of SPOT multispectral satellite imagery for classification of riparian vegetation along the Taieri River in New Zealand. In this paper, we discuss different sampling strategies for the classification of riparian zones. We conclude that SPOT multispectral imagery requires considerable interpretative analysis before being adequate to produce sufficiently detailed maps of riparian vegetation required for use in stream ecological research.     

Retrieving Hierarchical Information from Maps: The Role of Metric and Configurational Variables

Abstract

One of the most important challenges for cartographers is to be able to transmit information appearing in maps in a simple manner to users. The commonest strategy to do so consists in displaying visual information in a hierarchical way, that is, making it some elements to appear as being more important than others. Nevertheless, recent research has shown that people also pay attention to configurational information, or information about relationships among elements appearing in a map, to retrieve hierarchical information of it. This is the topic of this paper. It aims to investigate the role of metric and configurational information in enabling people to retrieve hierarchical information from maps. The main problem consisted in identifying ‘the main street’ of different layouts whose paths were sometimes widened to make them appear more important. The main findings show that people retrieved hierarchical information by paying attention to a combination of metric and configurational factors.

One of the main challenges that cartographers face is to transmit information in a way that is simple to understand for everyone. The most frequent strategy for this is to display the information in a hierarchical way; that is, by exaggerating the size or width of specific elements and thus assigning them a greater degree of importance. Nevertheless, recent research has shown that when reading maps, people also read configurational information. This is the topic of this paper. It aims to investigate the role of metric and configurational information in enabling people to retrieve hierarchical information from maps. For this, a set of exercises was designed and carried out where people were asked to identify the main street of different specially designed layouts. The main findings show that people retrieved hierarchical information by paying attention to a combination of metric and configurational factors.     

Unfolding the Earth: Myriahedral Projections

Abstract

Myriahedral projections are a new class of methods for mapping the earth. The globe is projected on a myriahedron, a polyhedron with a very large number of faces. Next, this polyhedron is cut open and unfolded. The resulting maps have a large number of interrupts, but are (almost) conformal and conserve areas. A general approach is presented to decide where to cut the globe, followed by three different types of solution. These follow from the use of meshes based on the standard graticule, the use of recursively subdivided polyhedra and meshes derived from the geography of the earth. A number of examples are presented, including maps for tutorial purposes, optimal foldouts of Platonic solids, and a map of the coastline of the earth.     

An Evaluation of the Use of Grid Squares in Computerised Choropleth Maps

Abstract

There are numerous computer programs to produce choropleth maps and some work has also been published on the use of a grid matrix as a way of dividing an area into discrete units. The purpose of this paper is to combine the two approaches and evaluate the suitability of using a network of grid cells, each containing a representative value of the variable being mapped, as a way of producing choropleth maps on a computer.     

Reviews

Abstract

Vegetation and rural land use show some of the greatest variety both in what and in how they are depicted on topographic maps. This paper discusses the various approaches that have been adopted to the selection of information to be shown on non-specialist maps. It also looks at the different ways in which vegetation and rural land use are depicted on a range of published map.     

Real World Map Reading Strategies

Abstract

A main component of an Intelligent Transport System (ITS) is the navigation system to be used in the 'intelligent' vehicle. In fact, driving a vehicle is a complex task as the driver has to control the vehicle as well as make decisions about getting to his/her destination. Too much information on the map (i.e. a complex map) would confuse the driver, while too little information would not be sufficient for the user to compare with the actual environment. Sufficient information but poorly presented would also result in confusion.

This paper reports on a study of the design of dynamic maps for land vehicle navigation through an investigation of different designs with different levels of information contents and visual effects using various dynamic variables. Different colours were assigned to the road and building names according to the position of the vehicle, and blinking symbols were used to indicate direction restrictions. Also, a set of maps with different degrees of complexity was designed such that the users would be provided with different levels of contents and representation by zooming in and out. The effectiveness of the design was investigated in the map evaluation process.     

A Structure Recognition Technique in Contextual Generalisation of Buildings and Built-up Areas

Abstract

A structure recognition technique is presented that can be employed for contextual building and built-up area generalisation in medium-scale topographic maps. Owing to various spatial configurations, a contextual mechanism is necessary to achieve acceptable results in cartographic generalisation. Spatial structures are usually implicit in data, and advanced analysis and processing methods are required to detect them. This technique is based on auxiliary geometric data structures and spatial analysis methods. A case study is performed with a topographic data set, using an interface developed in an object-oriented geographic information system (O-O GIS). The proposed approach was found to assist and improve automation.     

Cartographic Design and Production in the Internet Era: The Example of Tourist Web Maps

Abstract

Some, but not all, branches of the tourist industry make heavy use of maps. The industry has discovered the marketing potential of the Internet but in many cases has not yet fully exploited the extra potential of web maps compared to the traditional paper maps. Web maps can up-to-date tourist information very well but they have to be carefully designed to take account of the limitations of the medium. To be most effective, web maps should be basically simple and convey sufficient information interactively, on request. The map and symbol design should convey intuitively where and how this interaction can take place. This paper summarizes the typical faults found in tourist web map design and provides suggestions on good design practice.     

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.     

Reflections on Cartography as the British Cartographic Society Celebrates its Golden Jubilee

Abstract

A questionnaire to 128 drivers included map reading tasks using ½-inch to 1 mile maps produced by Philips (Shell Motoring Maps) and by the Ordnance Survey, followed by questions about which of the two maps was preferred and about the features required in a road map.     

MAPIT: A Computer Program for Production of Flow Maps,Dot Maps and Graduated Symbol Maps

Abstract

This paper describes some results of an attempt to design and to write a general purpose computer program which can be used to produce quality maps of discrete data by the person who has had no training in computer programming. In the first section, the variety of the maps this program can produce is illustrated; in the second section, some of the principles involved in such map production are discussed; in the third section, the input arrangements for using the program are described and, finally, the role of such programs in teaching and research in the years ahead is discussed.     

A heuristic multi-criteria classification approach incorporating data quality information for choropleth mapping

ABSTRACT

Despite conceptual and technology advancements in cartography over the decades, choropleth map design and classification fail to address a fundamental issue: estimates that are statistically indifferent may be assigned to different classes on maps or vice versa. Recently, the class separability concept was introduced as a map classification criterion to evaluate the likelihood that estimates in two classes are statistical different. Unfortunately, choropleth maps created according to the separability criterion usually have highly unbalanced classes. To produce reasonably separable but more balanced classes, we propose a heuristic classification approach to consider not just the class separability criterion but also other classification criteria such as evenness and intra-class variability. A geovisual-analytic package was developed to support the heuristic mapping process to evaluate the trade-off between relevant criteria and to select the most preferable classification. Class break values can be adjusted to improve the performance of a classification.     

NOTES ON THE USE OF THE SLIDE-RULE IN TOPOGRAPHICAL SURVEYING

Abstract

The Survey in which the following methods were employed was for a final map on a scale of 1/500,000, with contours at a 500-foot Vertical Interval. In order to make use of any available information shown on existing maps, the scale used in different areas in the field was that of existing maps. These scales were 1,000 roods to 1 inch (1 rood = 12.396 English feet), 840 roods to 1 inch (1/125,000), and 1,680 roods to 1 inch (1/250,000).     

A History and Analysis of Mapping Urban Expansion in the Kathmandu Valley,Nepal

Abstract

There have been numerous efforts over many years to map or delineate urban locations and features in the Kathmandu Valley of Nepal. This study acquired 27 land useland cover maps for the Valley or the urban portions of the Valley. Those maps vary greatly in their mapping parameters. The objectives of this study were to first conduct a cartographic comparison of the differences in the creation and content of the maps and then do an analysis of the urban changes in the Valley based upon the maps. The maps for the Valley have differed in their source materials, the amount of field work involved, scale and minimum mapping units, classifications used, definitions of classes and coordinate systems. Source materials have included various scales and formats of aerial photography and different satellite systems. The most difficult issue in comparing the maps is the varied classification systems and definitions. The same feature will be classified differently from map to map. This is particularly an issue for institutional features such as temples, palaces, educational facilities, open public space and governmental sites. Definitions of residential areas are also not consistent. Even with the differences in mapping parameters, considerable useful information can be obtained by comparing these maps. These include a simply documentation of the urban extent and the generally resulting loss in agricultural lands. There was an increase in urban extent from 22 to 83km² between 1955 and 2000. Urban expansion has also changed from occurring on the upland river terraces or tars to the floodplains. Finally, while not directly documented in these maps, the tremendous pace of urban growth has resulted in multiple infrastructure and environmental challenges.     

Investigating the Effectiveness of an Efficient Label Placement Method Using Eye Movement Data

Abstract

This paper focuses on improving the efficiency and effectiveness of dynamic and interactive maps in relation to the user. A label placement method with an improved algorithmic efficiency is presented. Since this algorithm has an influence on the actual placement of the name labels on the map, it is tested if this efficient algorithms also creates more effective maps: how well is the information processed by the user. We tested 30 participants while they were working on a dynamic and interactive map display. Their task was to locate geographical names on each of the presented maps. Their eye movements were registered together with the time at which a given label was found. The gathered data reveal no difference in the user’s response times, neither in the number and the duration of the fixations between both map designs. The results of this study show that the efficiency of label placement algorithms can be improved without disturbing the user’s cognitive map. Consequently, we created a more efficient map without affecting its effectiveness towards the user.     

Objective and Subjective Comparison in Choroplethic Mapping

Abstract

Visual map comparison can supplement statistical analysis by providing information as to where and how spatial correspondence occurs. The associations that may be discovered are influenced by the nature of the map features being compared and the criteria used for making the comparisons. In this paper the author has tried to identify the elements of visual recognition that map readers use to associate or differentiate geographical distributions represented by choropleth maps. The main components of the multivariate map reading process are pointed out, including the perceptual interactions between the actual locations of map tones and the overall similarity between map patterns.     

Understanding Chorematic Diagrams: Towards a Taxonomy

Abstract

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Chorematic diagrams are prospective candidates for communicating highly generalised geographic information about a given region of interest. Chorematic diagrams were popularized in France as the graphical artefacts of a specific school of geographic thought established by Roger Brunet, with GIP-RECLUS as his institutional backing. Although many maps were created and a lively debate ensued, only few consolidated cartographic findings were generated and even less were made known to the international scientific community. This article presents a contextualizing review and proposes a cartographic taxonomy aimed at being a first step towards efforts for the automated generation of chorematic diagrams.     

AIR MAPS

Abstract

That special air maps might be necessary was realised as long ago as 1909 when the use of maps in connection with balloons was being discussed: but there was little progress and Bleriot's flight in the same year imposed a completely new outlook. At first, with the air speeds common in the early days, it was possible for the aviator to use standard topographical maps on scales such as half or one inch to one mile and navigate by the identification of prominent landmarks. It was soon realised however that certain features were more outstanding than others and this observation was incorporated in one of the very first attempts to produce an "aero" map made in 1912. In this the roads, railways and lakes were emphasised by hand colouring on a photoprint of the one inch Ordnance Survey sheet. The practice of using, or hand amending, existing topographical maps continued in the early days of the 1914-18 war but the growth of the R.F.C. and the R.N.A.S. emphasised the need for specific air maps. By the end of the war the R.N.A.S. had special air charts for use over the coastal areas of the British Isles, and a special aviation map of France had been produced for the R.F.C. These maps were probably the first ever made in quantity for use in the air but they did not differ radically from the existing topographical series except in the simplification of certain detail and the showing of additional data of value to the airman -aerodrolnes, landing grounds, dangers etc. Air speeds were still not very high and flying was largely confined to fine weather so that the main form of navigation continued to be by the direct reading of maps.