利用CAD次开发程序计算超欠挖的研究

应用CAD平台进行二次开发,研究了超欠挖的计算方法,发现利用CAD平台计算超欠挖可实现计算过程自动化、可视化,并介绍了其工作原理、软件组成部分。结果表明,CAD二次开发程序能很好地计算隧道超欠挖。     

Arno Peters: The man and his map

Abstract

This paper shows an experiment with tactile maps designed for visually impaired persons. Tests were carried out on a tactile map produced with 3D printing and including a new type of tactile symbols, volumetric symbols (3D). These symbols are localized faster than conventional flat relief symbols, with the same error rate, an improvement in the use of these tactile devices. Moreover, following tests, differences were found between types of participants with blind participants generally carrying out the proposed tasks better than the rest of users.     

Influential Visual Design Parameters on TV Weather Maps

Abstract

Information transformation on television weather maps (TVWMs) is influenced by visual elements for a broad range of viewers. This research emphasizes the cartographic aspects of TVWMs through evaluating their visual variables. Currently defined visual variables including basic, dynamic and motion variables are investigated and some suggestions are made to improve their application on TVWMs. The rates of the represented visual information within different frames and the related standard deviation are proposed as measures to improve the performance of the ‘duration’ dynamic variable. The concept of ‘visual expressions’ is introduced, and their applications at the organisational level of map design are discussed. Such expressions (including background, boundary, spatial order, zoom and overview maps) are examined as tools for ‘user orientation’ in particular, and their role as dominant parameters in TVWMs’ cartographic communication is considered. Their incorporation in TVWMs of a number of global news channels is evaluated. Firstly, the concepts of visual design parameters are utilized as a foundation for an analytical evaluation, then an empirical evaluation is carried out based on a statistical investigation of a sample of TV viewers. The resulting ranking order and correlation coefficients for each of the elements shows a firm agreement, corroborating views on the importance and proficiency of the visual elements in communicating weather information. As a result, TVWMs of well-known global TV channels (BBC, Euronews, France24, PressTV) are ranked with respect to the effectiveness of their designs.     

Effective Graphic Features for Multivariate Symbol Mapping

Abstract

Various patterns of cartographic multivariate symbols (MSs) have been developed to work efficiently with objective symbol mapping. One such MS pattern is composed of a graph that uses spatial data to represent statistical data. A preliminary study revealed major problems with users’ perceptions and understanding of the symbol. These problems present obstacles to the presentation objectives. We are therefore interested in studying the human factors that contribute to the visual perception of graph symbols. We predict that the graph symbols currently in use are too complex for viewers to fully understand what they are intended to represent. This research aims to study the mechanisms and behaviours of human visual perception that are necessary to understand cartography MSs and to determine a more effective prototype symbol that presents and conveys information to viewers more efficiently. The prototype design is based on a basic cartographic symbol and includes the characteristics and properties of the original patterns of graph symbols via a study of their pros and cons. Graphic structures and properties were modified to create a more effective symbol.     

Evaluating the Efficiency of Typographic Design: Gender and Expertise Variation

Abstract

Although the efficiency of label placement algorithms has been studied extensively, few studies considered the influence of the label designs on the efficiency of map readers. Labels are one of the most important elements on the map as they can provide more information than other symbols can. The design of the labels does have to stress the theme, shape and functionality of the associated objects, which results in a more efficient interpretation of the map content by the user. How the label designs can enhance the map readers’ efficiency (and thus the quality of the maps themselves) is the main objective of this study. A user study was conducted in which the participants were asked to locate a target label on a map. Different label designs were implemented across the trials. The participants’ reactions times were registered to measure their efficiency and statistically analysed using a one-way ANOVA. Two different users’ characteristics were considered: gender and expertise. Related to the size, shape, orientation and texture of the labels, a number of significant differences (P<0·05) and trends were located. Differences in efficiency between males and females, on the one hand, and between novices and experts, on the other hand, were also described statistically. Consequently, recommendations can be formulated regarding the design of labels in order to obtain more efficient maps, keeping in mind the map users’ characteristics.     

Value-by-alpha Maps: An Alternative Technique to the Cartogram

Abstract

<title/>

The cartogram, or value-by-area map, is a popular technique for cartographically representing social data. Such maps visually equalize a basemap before mapping a social variable by adjusting the size of each enumeration unit by a second, related variable. However, to scale the basemap units according to an equalizing variable, cartograms must distort the shape and/or topology of the original geography. Such compromises reduce the effectiveness of the visualisation for elemental and general map-reading tasks. Here we describe a new kind of representation, termed a value-by-alpha map, which visually equalizes the basemap by adjusting the alpha channel, rather than the size, of each enumeration unit. Although not without its own limitations, the value-by-alpha map is able to circumvent the compromise inherent to the cartogram form, perfectly equalizing the basemap while preserving both shape and topology.     

Design and evaluation of a geovisual analytics system for uncovering patterns in spatio-temporal event data

ABSTRACT

It remains difficult to develop a clear understanding of geo-located events and their relationships to one another, particularly when it comes to identifying patterns of events in less-structured textual sources, such as news feeds and social media streams. Here we present a geovisualization tool that can leverage computational methods, such as T-pattern analysis, for extracting patterns of interest from event data streams. Our system, STempo, includes coordinated-view geovisualization components designed to support visual exploration and analysis of event data, and patterns extracted from those data, in terms of time, geography, and content. Through a user evaluation, we explore the usability and utility of STempo for understanding patterns of recent political, social, economic, and military events in Syria.     

Visual clutter reduction in zoomable proportional point symbol maps

ABSTRACT

Proportional point symbols are commonly used in map displays. However, when such displays are zoomed out, the available map space shrinks and consequently symbols overlap and the display suffers from visual clutter. Therefore, solutions are needed to reduce visual clutter in zoomable map displays that contain proportional point symbols. The authors add to the body of knowledge through the investigation of the performance of three solutions: aggregation of unit areas, the displacement of overlapping symbols, and modified symbolization; four variations of modified symbolization are examined in detail. The original study begins with a consideration of the strengths and weaknesses of the solutions, with an emphasis on information loss. Thereafter, user sessions with 165 participants are arranged to gain empirical evidence of the performance of the solutions. The results reveal that although participants zoom out the map to zoom levels that implement visual clutter reduction techniques, they tend to zoom in the map and pan it to examine specific areas. Moreover, they willingly use the map with aggregated unit areas in cases when the solution facilitates task accomplishment. A certain amount of skepticism attaches to the solution that displaces overlapping symbols.     

Contemporary American cartographic research: a review and prospective

ABSTRACT

We review recent developments in cartographic research in North America, in the context of informing the 29th International Cartographic Conference, and 18th General Assembly in 2019. The titles of papers published since 2015 in four leading cartographic journals yielded a corpus of 245 documents containing 1109 unique terms. These terms were analyzed using Latent Dirichlet Allocation and by visual analytics to produce 14 topic groups that mapped onto five classes. These classes were named as information visualization, cartographic data, spatial analysis and applications, methods and models, and GIScience. The classes were then used as themes to discuss the recent cartographic literature more broadly, first, to review recent trends in the research and to identify research gaps, and second, to examine prospects for new research over the next 20 years. A conclusion draws some broad findings from the review, suggesting that cartographic research in the future will be aimed less at dealing with data, and more at generating insight and knowledge to better inform society about global challenges.     

城市公益性专题地图编制技巧

以武汉市公益地图编制为例,结合多年来专题地图编制经验和市场调研情况,总结出一套行之有效的城市公益性专题地图编制技巧,具有一定的参考价值。