Developing Web-based Mapping Applications Through Distributed Object Technology

Emerging web-based mapping technologies use the World Wide Web (WWW) and Internet protocols to provide the ability to distribute, access, and visualize geospatial information over the Internet. Many web-based mapping applications have been developed to deliver geospatial information within and across organizations and even to the public at large. A major technological challenge is to achieve interoperability amongst web-based mapping applications so that mapping and geoprocessing resources distributed over the Internet can be shared and integrated. This paper presents an approach to the development of web-based mapping applications using distributed object technology in order to enable interoperability. Distributed object technology combines object technology, which utilizes reusable software components (called objects) that model real-world entities to build software systems, and distributed computing, which allows computing resources to be distributed and accessed over computer networks. The paper introduces a distributed object technology, the Common Object Request Broker Architecture (CORBA); proposes an architecture for web-based mapping using CORBA; and presents a prototype implementation.     

Allied Military Model Making during World War II

It is generally accepted that the three-dimensional nature of the digital terrain model enhances our visualization of surfaces. Modern techniques enable a detailed landscape to be constructed as a facsimile of reality that provides an opportunity to move through or fly over the landscape. Given these benefits, it is little surprise that simulations using digital terrain models are employed as essential visual aids for briefing and training military personnel prior to land, air, and sea operations. Though these capabilities are significant, they are not necessarily, in the basic sense, new. This paper traces the development and examines the role of terrain models made by the Allies during World War II, a period prior to the development of computer-based modeling. Though made from basic materials, these sophisticated terrain models were hand crafted by enlisted sculptors, architects, stage designers, and artists, who carefully modeled a sculpture of the landscape to be an invaluable aid during key military operations of World War II.     

Teaching Mapping for Digital Natives: New Pedagogical Ideas for Undergraduate Cartography Education

The current generation of US students engaging with cartography has always had some form of access to computing technologies. Further, this generation has always known a world with networked computer capabilities – the Internet and World Wide Web. Their experience of cartography is largely through fleeting representations shown on a variety of display screens, thereby encountering information differently than most of their instructors. Teaching cartography to these “digital natives” consequently challenges teachers to engage increasing levels of experience and knowledge of technology while assuring fundamental understanding of cartographic concepts and analysis techniques.

Although GIS is used in a vast range of fields, we believe many students are discouraged from programs and courses oriented towards educating cartographic specialists. However, general interest in mapping has never been as significant a part of American culture as it is today. In spite of accessible modes of digital mapping now widely available, introducing cartographic fundamentals retains great significance for undergraduate cartography education. In this paper we present a new pedagogical model for undergraduate cartography education that introduces students finding curiousity in mapping, but lacking desire to become cartographic specialists, to mapping. This model enables undergraduate students to learn fundamentals and begin to reflect critically on the concepts and techniques of modern cartography. Our example stems from a class that systematically addresses barriers to learning and mapping through active-learning based approaches in an interactive classroom. The active-learning approach involves significant engagements with the potentials and challenges of modern cartography in the information age by embracing inquiry-based pedagogical methods and learning with and about mapping.     

Using Eye-tracking and Mouse Metrics to Test Usability of Web Mapping Navigation

The growth of web-based mapping is transforming geovisualization. Use of web mapping has become ubiquitous throughout much of the world and has sparked greater public interest in GIS and mapping. Despite the rapid growth of web mapping, there has been relatively little study of the design and usability of web maps. Moreover, the design and function of popular web mapping programs are sometimes at odds with standard GIS and cartographic practices for even the simplest of functions such as zooming into a feature of interest. This study advances understanding of web mapping design via web usability testing based on mouse metrics and eye tracking technology to assess the utility of four different web map navigation schemes: pan zoom; double clicking; zoom by rectangle; and wheel zoom. We found significant differences among the various interfaces, with marked preference for the standard GIS approach of rectangle zoom, followed closely by wheel zoom. Far fewer users preferred the web mapping standard of pan zoom or click zoom. In addition to finding significant differences in usability among these approaches, this work illustrates the broader utility of usability testing and eye tracking technology for creating a better web mapping experience for users.     

ColorBrewer in Print: A Catalog of Color Schemes for Maps

ColorBrewer is a tool that assists mapmakers in choosing and creating color schemes. It is available online at <www.ColorBrewer.org>. The color schemes range from 3 to 12 classes and are organized into three basic categories: sequential, diverging, and qualitative. Each of these scheme types has general perceptual characteristics which are described using Munsell hue, value, and chroma specifications. Each scheme has been proofed from color-separated negatives and adjusted to offer CMYK (cyan, magenta, yellow, and black) specifications that produce a readable map when they are used in process-printed publications. This paper offers a printed catalog of all of the ColorBrewer schemes to allow mapmakers to evaluate the appearance of each scheme before they commit to using them in print publications. Since process-color proofing is expensive, this catalog will reduce mapmakers' costs and allow them to be more confident that their maps will make the transition from the desktop computing environment to publication without compromising the intended message through poor color specification.     

Geocollaborative Soil Boundary Mapping in an Experiential GIS Environment

Soil maps are an important and integral component of national geospatial data infrastructures. The creation of these maps involves a geovisualization exercise whereby soil scientists develop cognitive models that correlate observable landscape features to soil occurrence. This is traditionally an analog process, cognitively demanding, time consuming, and invariably non-collaborative. A new geovirtual soil mapping technique is proposed in this paper in the form of an innovative Experiential GIS (EGIS) environment. This immersive environment enables soil maps to be constructed through experiencing and interacting with spatial data through immersion in 3D geovirtual scenes. The system outlined integrates GIS, immersive geovisualization, and robust geodatabase capabilities. Four soil scientists with extensive soil mapping experience ranging from 5 to over 20 years are concurrently immersed in the same 3D geovirtual landscape which more closely mirrors the way in which we view the world around us. The soil scientists are immersed within the 3D scene where they are essentially freed from the laws of physics, and may roam anywhere across the landscape as if in a virtual helicopter. The landscape is draped with any combination of orthoimagery and GIS-derived data allowing soil scientists to interpret, digitally delineate, and attribute soil boundaries. Exploiting the EGIS technology while maintaining the centrality of the soil scientist in soil interpretation and soil map production, promises considerable resource efficiencies than those achieved in traditional soil survey. The paper lays out the nature of this potential paradigm shift in soil mapping. The results of using this technology to construct soil geographic knowledge are also discussed in terms of soil map detail, cost efficiencies, time effectiveness, system usability, geocollaborative soil mapping advantages, and the reduced cognitive workload on practicing soil scientists.     

Establishing Classification and Hierarchy in Populated Place Labeling for Multiscale Mapping for The National Map

Current standards for federal mapping call for use of the Geographic Names Information System (GNIS) point layer for placement of United States populated place labels. However, this point layer contains limited classification information and hierarchy information, resulting in problems of map quality for database-driven, multi-scale, reference mapping, such as maps served by The National Map Viewer from USGS. Database-driven mapping often relies simply on what labels fit best in the map frame. Our research investigates alternative sources for labeling populated places, including polygons defined by the U.S. Census Bureau, such as incorporated place, census designated place (CDP), and economic place. Within each of these polygon layers we investigate relevant attributes from the decennial and economic censuses, such as population for incorporated places and CDPs, and the number of employees for economic places. The data selected are available for the entire country to serve national mapping requirements. This combination of data allows a more refined classification of populated places on maps that better represents relative importance. Visual importance on maps through scale should derive from more than simply residential population, but also economic importance, though comparison is made to this simpler case. We differentiate a fourth category of GNIS populated place points, essentially “neighborhoods” and related features—which are not incorporated places, CDPs, nor economic places. Populated places in this fourth class do not have federally defined boundaries, necessitating an alternative method for determining hierarchy in label presentation through scale.     

Testing the Effects of Thematic Uncertainty on Spatial Decision-making

Dasymetric mapping techniques can be employed to estimate population characteristics of small areas that do not correspond to census enumeration areas. Land cover has been the most widely used source of ancillary data in dasymetric mapping. The current research examines the performance of alternative sources of ancillary data, including imperviousness, road networks, and nighttime lights. Nationally available datasets were used in the analysis to allow for replicability. The performance of the techniques used to examine these sources was compared to areal weighting and traditional land cover techniques. Four states were used in the analysis, representing a range of different geographic regions: Connecticut, New Mexico, Oregon, and South Carolina. Ancillary data sources were used to estimate census block group population counts using census tracts as source zones, and the results were compared to the known block group population counts. Results indicate that the performance of dasymetric methods varies substantially among study areas, and no single technique consistently outperforms all others. The three best techniques are imperviousness with values greater than 75 percent removed, imperviousness with values greater than 60 percent removed, and land cover. Total imperviousness and roads perform slightly worse, with nighttime lights performing the worst compared to all other ancillary data types. All techniques performed better than areal weighting.     

Integrated Mobile GIS and Wireless Internet Map Servers for Environmental Monitoring and Management

With the progress of mobile GIS technology there is a great potential for adopting wireless communications and Internet mapping services for regional environmental management programs and natural habitat conservation. This paper provides an overview of a NASA-funded research project that focuses on the development of mobile GIS tools and wireless Internet Map Server (IMS) services to facilitate environmental monitoring and management tasks. By developing and testing wireless web-based map/image servers, mobile GIS applications, and global positional systems (GPS), this research created an integrated software/hardware infrastructure for a prototype mobile GIS application. The mobile GIS prototype allows multiple resource managers and park rangers to access large-size, remotely sensed images and GIS layers from a portable web server mounted in a vehicle. Users can conduct real-time spatial data updates and/or submit changes back to the web server over the wireless local area network (WLAN). This paper discusses in general the major components of mobile GIS, their current technological limitations, and potential problems during implementation. Key research agenda for mobile GIS are identified with suggestions for future research and development.     

Multiparametric Cartographic Visualisation of Glacier Rheology

Abstract

In cooperation between remote sensing experts and cartographers interested in glaciology, new types of maps showing the glacier dynamics have been developed. The maps make use of the original phase gradient approach to glacier rheology modelling based on repeat-pass ERTS SAR interferograms. Careful map design and, in particular, colour assignment allow the visualisation of the glacier dynamics in its locally changing velocity with an estimated accuracy of approximately 2.0 cm per day. Two map derivates – a differential interferogram showing the glacier velocity and another product displaying the glacier strain rate – have been designed. Moreover, maps displaying the glacier marginal changes within the space of four years have been generated. The strain rate maps evidence that spots with high values frequently correspond with crevasse-prone areas which are even detectable under thick layers of snow. In this sense, the latter visualisations can be seen as maps of crevasse danger zones. The Svartisen in Norway and the Hintereis Glacier in Austria served as testbeds for the development of these different types of maps which are at the scales of 1:25 000, 1:50 000 and 1:100 000.