Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 43
A Research Agenda for Geographic Information Science at the United States Geological Survey 3 Research Priorities This chapter addresses the committee’s third task—to make recommendations regarding the most effective research areas for the Center of Excellence for Geospatial Information Sciences (CEGIS) to pursue. The need for prioritization is the clear driver for this study—for, as noted earlier, there are many more research challenges than even the most optimistic assessment of CEGIS’s future resources can support. The committee has already established the need for, and recommended an initial focus on, research to support The National Map (Chapter 2). This chapter describes and recommends research priorities under that overarching theme. Although other research topics such as visualization, cognition, and land use or land cover change are very important, the committee feels that enhancing The National Map will optimize initial efforts while leaving open the possibility of expanding to other topics mentioned by McMahon et al. (2005) in due course as resources allow. The chapter has two parts. The first part describes the committee’s approach to determining priorities and applies the resulting prioritization criteria to yield an initial set of priority research areas for CEGIS. The second part delves more deeply into priority research topics that fit within each of the three general research areas and demonstrates how these priorities are interrelated within The National Map. In the long run, this set of priorities will have to adapt to changing U.S. Geological Survey (USGS) needs and resources.
OCR for page 44
A Research Agenda for Geographic Information Science at the United States Geological Survey PRIORITY RESEARCH AREAS This section defines and applies criteria for the prioritization of CEGIS research. The committee deliberated on candidate criteria based on information from meeting participants, interviews, and other inputs (Appendix B). Not only do the criteria help define broad research areas, they point to more specific priorities among focused topics within these areas. Consequently, the criteria are used again later in this chapter. The committee’s eight prioritization criteria for CEGIS research follow: Prioritization Criteria for CEGIS Research Importance to The National Map. The National Map is a critical product and service of the USGS and, in particular, of the National Geospatial Program Office (NGPO). Consequently, an initial research emphasis on serving the needs of The National Map is a high priority. Furthermore, if applied to enhancing The National Map, the results will be a visible and high-profile measure of the success of such research. Importance to USGS disciplines. After serving the needs defined by The National Map, the most important constituencies for CEGIS are the USGS disciplines. discipline needs and The National Map needs are not mutually exclusive. New capabilities for The National Map described in Chapter 2 are envisioned to serve the disciplines and multidisciplinary interactions. Relevance to society. CEGIS serves not only USGS but also the nation. Its research projects will have to demonstrate high relevance to society. Solves a problem and targets a customer. At this early stage in CEGIS’s evolution and with limited resources, CEGIS will have to focus on applied research with measurable payoff. Solving key customers’ problems should receive high priority. Foundational, understandable, and generalizable. CEGIS’s most important projects will be those that solve problems in geographic information science (GIScience) that have general applicability to the field and are easily comprehensible by users and customers. A measure of success in this criterion would be acceptance of CEGIS research results in a peer-reviewed publication. Enables multidisciplinary integration. Due to the wide variety of users of CEGIS’s research, the most effective research will be that which serves the widest breadth of users and supports an “enterprise solution.” Focus on content. Content is the defining ingredient provided by the USGS—whether from The National Map or elsewhere. CEGIS’s research will need to focus on content-related issues. CEGIS may at times do
OCR for page 45
A Research Agenda for Geographic Information Science at the United States Geological Survey conceptual design of tools, but tool development is considered part of development engineering. Potential for early, visible success. As with any organization, CEGIS has strongest prospects for longevity and value to USGS if it achieves and builds on early successes. CEGIS will need to target programs with this in mind. It is important to note that these criteria are intended only as a starting point for CEGIS. From here it is essential that CEGIS continue to review this prioritization as well as take it to the next level of detail to resolve further trade-offs on what to do first within the available resource pool. These criteria for prioritizing CEGIS research point toward a program of research areas with underlying focused topics that supports users of The National Map data content and produces visible results in a short period of time. Research Areas Three broad research areas emerged from the committee’s deliberations on the eight prioritization criteria: Investigating New Methods for Information Access and Dissemination. Access to information content is a key success factor at many levels for The National Map. The USGS disciplines need effective data access to carry out their missions. Other federal and state agencies need effective interfaces to The National Map content so that their organizations can maximize productivity when working with national and local data. This priority also supports society in general because citizens need a trusted, up-to-date source of geospatial data for the nation that is flexible and easy to use. In addition, this is an area with potential for visible early success enabling interim milestones in CEGIS’s longer-term research agenda. Supporting Integration of Data from Multiple Sources. Given the diversity of source data from state and local agencies as well as many add-on themes and the desire for multidisciplinary research across USGS, achieving efficient and accurate data integration is fundamental to the effectiveness of The National Map. Within USGS, researchers in the various disciplines will need to find common reference data in The National Map and be able to load and share their data. Furthermore, the types of models and forms of spatial analysis that are increasingly needed to solve social and environmental problems will require that spatial data sets can be integrated on the fly. CEGIS will need to find solutions to integrating data with different semantics and widely varying quality, scale, and spatial and temporal granularities and resolution. Developing Data Models and Knowledge Organization Systems. To support society in general, The National Map will need both the semantic flexibility of a
OCR for page 46
A Research Agenda for Geographic Information Science at the United States Geological Survey well-designed framework and models that enable a variety of user requests for information and information products. This objective will likely require the most research effort, but it will deliver enormous power to The National Map applications and lead to its clear differentiation from other web-based products. Because all three research areas are core geographic information science research areas that are of general interest to the broad GIScience community in addition to USGS (see, e.g., DiBiase et al., 2006), CEGIS will be able to leverage ongoing research activities in this broader community. The arguments presented above lead to the following recommendation: RECOMMENDATION 2: The three priority research areas for CEGIS should be (1) information access and dissemination, (2) integration of data from multiple sources, and (3) data models and knowledge organization systems. PRIORITY RESEARCH TOPICS Authorities were notified early yesterday of a fire raging in the hills around San Diego. The local fire district office immediately accessed The National Map and displayed a topographic map of the area, including known fire trails in the hills and water resources. Given the terrain, fuel supply and impending weather, the team realized that it had a very difficult challenge on its hands and team members would be depending on technology, as well as the hard work of their crews, to deal with the crisis. To bring the discussion of a GIScience research agenda to life, we have woven into the remainder of this chapter firefighting and management examples in the form of a scenario of the use of The National Map to manage and fight a wildfire in San Diego, California. Geospatial information and tools are useful in wildfire risk assessment, modeling, monitoring, and firefighting, emissions modeling, and burn scar mapping (Rothermel, 1972; Radke, 1995; Clinton et al., 2006; Gong et al., 2006). Firefighting can benefit from accurate static geospatial data (e.g., topography) as well as dynamic information (e.g., fuel and weather) viewed in a spatial context. Improved data access, data integration, and data modeling and knowledge organization are all key to an enhanced National Map that can more effectively serve fire management applications as well as many others. (Note that these scenarios are intended for illustration purposes only and are not intended to reflect actual current or planned capabilities). Each of the recommended broad research areas from the previous section encompass a range of focused research topics. These also need to be prioritized for CEGIS’s research portfolio. The following three subsections describe in detail these research topics and, drawing again on the prioritization criteria listed earlier, recommend the two highest-priority topics under each research area. The order of these
OCR for page 47
A Research Agenda for Geographic Information Science at the United States Geological Survey three subsections is driven by which research areas will likely result in early “wins” for CEGIS. Consequently, the subsections progress from near-term toward the longer-term and more challenging research. All of the research topics identified could span a broad range from basic to applied research. To provide context for the state of the art, the discussion generally begins with a description of the basic nature of the topic and lists references to relevant research. However, the recommended research questions are focused on applied research since they are motivated by the goals of The National Map and therefore are aimed specifically at how this research will advance the capabilities of The National Map. Of course, the application of this applied research does not stop with The National Map and will serve the other USGS disciplines as well as other agencies and users in the field. In this way, the leadership of the USGS and NGPO is demonstrated not only by the creation of a powerful National Map, but also by the far-reaching influence and value of the applied research the agency conducts. Each subsection provides a general explanation of the problem; describes the relationship of the focused research topics to the USGS context (its relevance to The National Map, NGPO, and/or any of the USGS disciplines); and describes the maturity of the problem, approximate time frame to complete the research (near term or longer term) and in which organizations the research center of gravity resides. Although the committee did not evaluate the potential duration of research projects in great detail, in general short term is considered to be one to four years, and long term four to eight years. Three presentation tools are utilized in this section to help clarify the main points and tie the material together. First, the specific research questions offered under each topic as starting points for CEGIS research are collected in a summary table in the final section of the chapter. Second, the aforementioned scenarios of wildfire management and operations are revisited in each subsection to illustrate how the proposed research relates to an operational application. Third, the committee uses Figure 3.1 to illustrate how the research areas and topics are linked in the context of The National Map. Figure 3.1 illustrates the relationship of the recommended research topics to the overall framework of The National Map introduced in Figure 2.1, addressing most of its components. Colored boxes are research topics that would add a new capability or feature to The National Map and the three colors relate to the three research areas discussed in this chapter. The pink boxes and arrows indicate research topics covered in the section on Information Access and Dissemination. The blue boxes and arrows indicate research topics covered in the section on Integration of Data from Multiple Sources. Research topics in the yellow boxes and arrows are covered in the section on Data Models and Knowledge Organization Systems. The committee’s six recommended priority research topics for CEGIS are bolded in Figure 3.1. Box 3.1 describes how research in these areas would enhance the capabilities and functionality of The National Map.
OCR for page 48
A Research Agenda for Geographic Information Science at the United States Geological Survey FIGURE 3.1 A potential framework for The National Map of the future and areas of GIScience research for CEGIS that will fuel its evolution. Recommended priority research topics are in bold within the colored boxes and arrows. This framework is adapted from that in Figure 2.1 and emphasizes The National Map aspects of the diagram—not those relating to the National Atlas. NOTE: API = application programming interfaces. CSW = Catalog Service for Web; EPA = Environmental Protection Agency; NASA = National Aeronautics and Space Administration; NOAA = National Oceanic and Atmospheric Administration; OGC = Open Geospatial Consortium; WCS = Web Coverage Services; WFS = Web Feature Services; WMS = Web Map Services.
OCR for page 49
A Research Agenda for Geographic Information Science at the United States Geological Survey Box 3.1 Benefits of the Research Topics to The National Map Information Access and Dissemination Reinvented Topographic Maps Provide easy public access to a valuable USGS product User-Centered Design Improves usability of the human interface Easy access to high-quality maps in various media High-quality printing for all users OGC Standard Profiles Facilitate a systematic framework for a distributed National Map computing system Integration of Data from Multiple Sources Data Fusion Integration of dissimilar data types enriches The National Map database Facilitates integration of local data with various scales, types, etc. Generalization Allows automatic scaling of output to user’s needs Data Models and Knowledge Organization Systems Geographic Feature Ontologies Specify feature semantics for richer data models Ontology Driven Data Models and Gazetteers Organize data to support queries by place name, feature types, feature parts and multple representations Quality-Aware Data Models Add ability to automatically assess quality of diverse input data Data Models for Time and Change Analyze and track land feature changes Transaction Processing Supports frequent data updates from distributed sources The current version of The National Map has created an excellent field test of a prototype or beta version from which to build. The current National Map implementation reveals its strengths as well as its limitations. In fact, it is probably true that the only way to understand the highly complex information system design needs of The National Map is to field a prototype and measure its good and bad points. To break through the technology barriers that stand between the current National Map and the way it is envisioned in Figure 3.1, a thorough review of the system design is warranted. The committee has suggested one possible scenario (Box 2.2) based on current capabilities and trends, but in the long term The National Map system design team within USGS would feed requirements-based research challenges to CEGIS that would undoubtedly result in adjustments to the set of priorities listed in this chapter. The National Map of the future is envisioned to be a highly dynamic and flexible transactional information system. Those transactions occur on both the input and output sides of the system, with the powerful concept of seamlessly integrating local feature level granularity data into the database in real time. A
OCR for page 50
A Research Agenda for Geographic Information Science at the United States Geological Survey wide diversity of users access data, use tools to geospatially and temporally analyze data, and construct products and tools on top of The National Map in sessions with application programming interfaces on the output side. The magnitude and breadth of these transactions define the potential value of The National Map, but also create an information system design challenge. In addition to the influence of evolving capabilities in GIScience research and technology on the potential framework of The National Map, broader trends on the web1 will inevitably affect its architecture because the web is the delivery platform for The National Map. These trends will, for example, push an enhanced National Map toward a service-oriented rather than system-oriented approach, a collective intelligence rather than a single knowledge base, data as the driving force, lightweight user interfaces and development models for fast and reliable system performance, mapping software that supports multiple devices (e.g., personal digital assistant [PDA], cellular phone), and direct feedback opportunities that support rich user experiences and user participation. Information Access and Dissemination Wildfires are spreading rapidly across a San Diego mountainside. Firefighters have deployed with two-way radios and Global Positioning Systems (GPS). In the command center, the new three-dimensional topographic maps overlaid with near-real-time airborne color-infrared thermal imagery, real-time GPS wireless sensor data, and National Weather Service maps of wind direction, precipitation potential, and temperature displayed on the computers allow the command center team to tell the firefighters where the wildfire boundaries are and help them estimate the likely fire spread directions and speed in the next two hours The operators at the command center find it intuitive to toggle between the various layers of data to analyze the situation and can select different combinations to produce PDF files for fast printing to distribute to the crews. Meanwhile, the GPS and wireless communication enable the transmission of the position of the crew back to the command center, which has a large screen to display the overview maps with current positions of all firefighters and current fire perimeters. With comprehensive geographic information system (GIS) modeling technology and the information provided from The National Map (topography, slope, aspect, weather, soil moisture, vegetation, etc.), the command and control center calculates potential dangers for firefighters and immediately distributes a warning to the crews on the west side of the mountain to relocate 300 m farther west. Based on information from the overview maps, the center also dispatches another crew to 1 See http://www.oreillynet.com/pub/a/oreilly/tim/news/2005/09/30/what-is-web-20.html.
OCR for page 51
A Research Agenda for Geographic Information Science at the United States Geological Survey the highest-risk zone and moves two more toward that zone. Their earlier participation in design phases is paying off in powerful but easy to use geospatial tools in a frantic and hostile environment. A well-designed and user-friendly web mapping service is essential for effective use of USGS data and map products. The design of web-based USGS mapping applications is a great challenge because users can change the contents immediately by manipulating map browsers in such simple functions as zooming in, zooming out, or changing layers. The communication mechanism between map production and map users has never been as immediate and important as it is now in the rapidly expanding web mapping environment. The three GIScience research topics described in this section contribute to improved web services and map display—with the ultimate goal of improving accessibility and usability of USGS products. These topics, listed in the committee’s recommended priority order based on the criteria presented earlier and beginning with the highest priority, are: Innovative formats and designs to reinvent topographic maps in an electronic environment; User-centered design (UCD) for implementation of The National Map web services; and Open Geospatial Consortium (OGC) Standard Profiles for The National Map web mapping services and map layer design. This subsection covers each of these foci in the order presented above. The first two topics need immediate action by CEGIS because of their fundamental value to users of The National Map and the potential for near-term, visible success. RECOMMENDATION 3: The two priority research topics within the area of information access and dissemination should be to reinvent topographic maps in an electronic environment and to investigate user-centered design for The National Map web services. Priority CEGIS Research Topic: Innovative Formats and Designs to Reinvent Topographic Maps in an Electronic Environment Topographic maps are the one of the most important products of the USGS and The National Map. They were established in the nineteenth century (Thompson, 1988) and are the USGS’s most recognized and popular map product. In the digital mapping age, CEGIS has the opportunity to conduct research that will transform the well-designed traditional paper topographic
OCR for page 52
A Research Agenda for Geographic Information Science at the United States Geological Survey maps into an electronic, web-based, multipurpose utility. Effective delivery of topographic maps will serve both society and professionals who use this information as a base layer for analyses. This work requires immediate attention by CEGIS and can be accomplished in the short term (one to four years)—drawing in particular on the expertise of USGS’s many well-trained cartographers in collaboration with software vendors with established technologies for map display. As illustrated in the vignette at the start of this section, well-designed three-dimensional electronic topographic maps will become a critical source of information in such applications as wildfire spread predictions and emergency response. Two research foci are of particular and immediate value to the cartographic display of The National Map: (1) development of PDF topographic maps for wide distribution and (2) development of foreground and background data layers for control of visual hierarchies in each of the eight data layers for which USGS has responsibility in The National Map. These two foci arise because the available methods for creating online topographic maps using The National Map viewers are fairly complicated for public use—users must often select layers and symbols from among hundreds of choices; alternatively, they are confronted with a map made with all themes as strong high-contrast symbols—sometimes with confusing color choices (Figure 3.2). PDF Topographic Maps. In the simplest case, CEGIS could develop PDF topographic maps with an associated specialized map viewer. PDF is preferred because it retains the resolution needed in print products, has wide distribution, and would accommodate viewing, saving, and printing maps by users with the most minimal computing capabilities. All topographic map symbols and layer contents are predefined by USGS cartographers. Topographic map symbol colors, widths, textures, shapes, and sizes could mimic the existing map style if scale is restricted to 1:24,000, for example. CEGIS research needs to address design changes that accommodate changes in scale and resolution. Existing point, line, and area elements can be used at a range of scales and resolutions with minor adjustment to symbols and selection of features (Brewer and Buttenfield, 2007). Changes in symbol size and shape, line width, use of outlines, color, transparency, and texture all extend the readability of map data without requiring geometric changes through generalization.
OCR for page 53
A Research Agenda for Geographic Information Science at the United States Geological Survey FIGURE 3.2 Multicolor forest fragmentation theme (upper pane) that interferes with the base information overlaid on it (shown separately in the lower pane). Red, blue, and black symbols in the forest theme are the same color as the base elements, making them ineffective location cues despite simple and consistent display choices. SOURCE: USGS (http://nationalatlas.gov). Research Question: What is the widest range of scales that can be mapped only by adjusting map symbols combined with selectively removing feature types? (short term) Research Question: What is the minimum amount of change to map symbols and content that provides the maximum scale range maintaining topographic map usability? (short term) Advanced use of the PDF to deliver topographic maps could make use of Optional Content Groups (OCG) (Adobe Systems Incorporated, 2004). OCG
OCR for page 88
A Research Agenda for Geographic Information Science at the United States Geological Survey Standardization of operational definitions for topographic features and hence feature footprints can lead to standardized algorithms for feature footprint extraction rather than many ad hoc approaches. Quality-Aware Data Models Uniformly high-quality data has been a signature characteristic of USGS topographic information. Given the changing environment in which many heterogeneous sources now contribute to the databases of The National Map, new challenges for data quality assessment and management arise. In the past, quality control was standards driven, and generally externally and globally applied. In other words, whole data sets were compared to independent sources of higher accuracy to assess compliance with the standard. In an environment where new data may be submitted in small increments as updates on individual features in a spatially and temporally ad hoc manner and from diverse sources, new methods to assess data quality need to be explored. An internally managed approach in which the database has built-in redundancy and benchmarks to assess quality offers some promise. A feature database that supports multiple spatial versions of the same features at different levels of detail or different temporal states creates the opportunity for such a quality-aware data model. Multiple versions of features create replicates and the potential for empirical distributions on features states. Imagine many versions of the boundary of a lake collected over time and with different levels of detail from several different sources. As a database accumulates these versions, it begins to have the information to identify means, medians, and percentiles for feature attributes including locations. Such a strategy creates a trade-off in storage overhead for multiple versions but with the benefits of enhanced quality assessment. Tu et al. (2005) examine this problem of multiple-quality replica selection subject to an overall storage constraint. If each feature has a distribution of observed values for its various properties, the database can be designed to work with these distributions for various quality assessment tasks. These distributions can be used for example as a basis to evaluate and categorize incoming transactions from local cooperative partners. Suppose a partner submits a new GPS-generated road segment and suppose several versions of this road segment are stored in the database. The new submission can be compared with the existing set to see if it is an outlier (i.e., could represent a legitimate change, or an error) or falls “close” to the mean of the set. Such a concept raises a number of longer-term research questions around which a coherent research initiative could be built. In particular, Research Question: How can sampling distributions of complex objects be defined and managed (e.g., reduce them to points in some N-dimensional shape space)? (long term)
OCR for page 89
A Research Agenda for Geographic Information Science at the United States Geological Survey The expectation is that multiple spatial versions of features would follow a normal distribution, but statistical tests would require specification of means and variances for these complex objects. Work at the University of Maine has investigated Least Squares Collocation (LSC) and geostatistics as positional accuracy diagnostics tools (Agouris et al., 2001). The potential of simulated versus empirical sampling distribution could be explored. Various types of feature update transactions could then follow from distribution specifications. For example, new versions of a feature that are close to the mean might be rejected as redundant. Outlier versions might also be rejected as errors or alternatively checked and retained as important variants due to change or temporal state. This is a new area of research in terms of context (i.e., embedding quality assessment within database transactions for complex spatial objects), but it can bring to bear ongoing work on least squares, geostatistics and high-dimensional statistics, indexing, and dimension reduction. Data Models for Time and Change The National Map data model does not now support explicit representation of temporal states, change, and dynamic relationships among geographic features. Consequently, there is no framework for storage, retrieval, and access to previous states of geographic features, changes, and events. For example users cannot query for past states (e.g., “get flood states for the Kennebec River for the last five years”); query for feature states within a specified time interval and spatial range, and display returned states (e.g., “retrieve the state of lakes for April 1-15 for latitudes 44-45 degrees”); or ask for projected views for future states (what is the expected water level in Lake X for the month of April?). A range of physical process models including fire behavior models, ecosystem phonological modeling, and disease spread models (see McMahon et al., 2005, for more examples) require spatiotemporal inputs and could benefit substantially from the addition of the time dimension to The National Map. The history of spatiotemporal models for GIS (Armstrong, 1988; Langran, 1992) begins in the late 1980s. Early work viewed the central unit of analysis as the spatial layer and change was conceived as modifying the fabric of a layer (Langran, 1992). More recent views include an object change view and an event view. Spatiotemporal information queries can then be done based on various spatiotemporal models (Yuan and McIntosh, 2002). Object change-based data models (Abraham and Roddick, 1999; Worboys, 2005) can track changes in geographic features. In contrast, the event-based model focuses explicitly on tracking the change itself (Claramunt and Thériault, 1995; Peuquet and Duan, 1995; Worboys and Hornsby, 2004; Worboys, 2005; Beard, 2006). While the object-based model records the changes in the property of an object, the event model considers change as the explicit entity of interest.
OCR for page 90
A Research Agenda for Geographic Information Science at the United States Geological Survey For example, assume that the average pH of a lake changes over the course of a year. In the object-based model the primary object is the lake and one would track pH changes as non-spatial property changes to the lake. In the event view, a change itself, for example an abrupt drop in pH, is the specific entity of interest along with type specific event properties such as intensity, time of onset, duration, or cessation, and location. The USGS science strategy strongly advocates development of methodologies for change analysis and The National Map has a role to play here. Data model enhancements that support time, change, and events are therefore central to the interdisciplinary science agenda of the USGS. While The National Map has adopted the role of the topographic map as a framework for spatial information integration, it may be further investigated as a framework for spatiotemporal information integration. Records of events and processes are a basis for understanding dynamic behaviors, and USGS is already collecting and accumulating event data (seismic events, landslides, etc.). Environmental monitoring by other agencies and emerging sensor networks are creating repositories of information with high temporal resolution that support the analysis of change. Additionally, physical process-based spatiotemporal models that produce spatial snapshots in time at regular intervals (e.g., hourly, daily, annually) are used widely in such fields as hydrology, ecology, and biogeography. These models make use of geographic information layers as input but are not well accommodated by traditional GIS databases. It is important to have data models that are both spatially and temporally explicit. This is particularly the case in USGS where hydrologists, ecologists, and geographers are adopting more quantitative modeling tools and considering using geospatial data to calibrate models or vice versa. Therefore, research in this area could have great benefits to other USGS disciplines and other scientific agencies in developing new techniques for combining and analyzing spatiotemporal data. A role for The National Map in such a setting is to provide the appropriate temporal as well spatial contexts in which to analyze change or event data and support spatiotemporal process models. As an example, suppose researchers have detailed spatial records of burn scars for a set of historic wildfire events and they wish to run a fire model to examine how well the model can replicate such events. Assume the fire model runs over a detailed landscape-terrain representation that include roads, structures, and land cover. The researchers want to assemble the landscape settings that are most temporally consistent with each fire date. Ideally the researchers should be able to search The National Map database for the spatial and temporal location of each fire event and retrieve temporal versions of the terrain, roads, structures, and land cover most consistent with the fire date. Such a scenario illustrates one potential spatiotemporal support role for The National Map by CEGIS that could be addressed in the long term.
OCR for page 91
A Research Agenda for Geographic Information Science at the United States Geological Survey Research Question: What can be learned from spatiotemporal use cases for advancing spatiotemporal models for The National Map? (long term) Research Question: How is change effectively represented in spatial data sets? (long term) Research Question: How can process-based models be used to improve data quality or quality awareness in The National Map? (long term) Semantics-Driven Transaction Processing The contribution of data to The National Map and other USGS databases from multiple local data sources and partners has a real benefit in improving the update cycle and easing the burden of centralized data collection. Indeed, distributed, locally based geographic data collection stands to substantially help the USGS maintain current, locally verified, comprehensive databases of geographic information. However, such an approach can create a substantial new burden for transaction processing (insertions, modifications, and metadata management) on these databases. Insertion transactions are likely to become much more frequent (e.g., as sensors generate near-continuous data streams), pertain more to individual features, and generate more complex metadata records given that data sources may include many different heterogeneous technologies with potentially quite different accuracy or quality characteristics. Transaction processing also becomes more complex in the more complex data model environments described above. Revisiting the fire example, let us assume that the firefighters collected information on portable computers or from deployed sensors in the field as they were fighting the fire. At the end of the day, the goal is to distribute this information as updates to appropriate databases. Suppose the information collected by the firefighters includes estimates and extents of burned areas and an inventory of burned structures. Several long-term questions arise on what the transaction processing logic is for updating National Map or other USGS databases. The firefighters are not expected to be database experts and so need support for simply uploading the data. There is, however, complex transaction processing logic that stands behind uploading these data to the correct databases. For example the records of burned areas could be added to a fire events database. In addition, it may be appropriate to update a set of land cover databases and associated products. The National Map includes several land cover and associated products, and the transaction logic would have to consider whether some or all of these should be subject to fire updates. The transaction logic might be such that only those products in which the resolution or granularity of cover classes matches the extent of the burn area are subject to updates. Coarse land cover products might be immune to small burn area updates. On the other
OCR for page 92
A Research Agenda for Geographic Information Science at the United States Geological Survey end of the granularity spectrum, if the fire data are sufficiently detailed to indicate differential burn on different cover types, the transaction logic might be that differential burn damage information is applied to different land cover classes. The information on destroyed structures requires similar sets of transaction decisions. Presumably the structures database should be updated with information that structures X, Y, and Z were destroyed by fire on the given date. A follow-on question could be what additional databases and sources should be updated? For example, should any high-resolution images depicting these structures be updated? Research Question: What is the transaction processing logic for complex spatiotemporal transactions among National Map and other USGS databases? (long term) Research in this area resides predominantly in the database research community. Transaction processing generally is a mature field, but spatial and temporal transaction processing and transaction processing in distributed database contexts are still new. The OGC Transaction Web Feature Server is addressing the ability to create, update, and delete geographic features in a distributed computing environment and CEGIS may consider some collaborations with OGC in developing distributed National Map transaction processing. Open research issues remain with respect to spatial transaction processing on multiresolution databases. Kafeza et al. (1996) and Rigaux and Scholl (1995) describe approaches to transaction processing in multiscale and multiresolution environments, and there is relevant work on transaction processing for mobile systems (Hampe and Sester, 2004). Hampe and Intas (2006) have recently proposed extensions to OGC Web Feature Services standards to support transactions on multiple representation databases. Transactions in spatiotemporal databases must address issues of when or how frequently new versions or states of feature properties are updated. Some update transactions may be event driven as in the case of the fire event described above. CEGIS might investigate what USGS or other agency databases record events (e.g., earthquakes, landslides, floods) and consider the automation of National Map database update transactions in response to such events. SUMMARY This chapter has laid out a recommended research priority structure for CEGIS, with three priority research areas, each broken down into research topics. The two highest-priority topics are recommended for immediate action in each area, with other important topics described as well for the purposes of longer-term research planning. Specific research questions for each topic are
OCR for page 93
A Research Agenda for Geographic Information Science at the United States Geological Survey also suggested as potential starting points. Table 3.1 summarizes this research structure and is organized to show the broad research areas, the recommended research topics within those areas, and the committee’s suggested initial research questions. Building on this foundation as resources allow and requirements evolve, CEGIS can expand its research portfolio to address a broader range of key GIScience issues of national relevance.
OCR for page 94
A Research Agenda for Geographic Information Science at the United States Geological Survey TABLE 3.1 Summary and Time lines of Recommended CEGIS Research Areas, Topics, and Questions Research Area Research Topic (Bold = Priority Topic) Research Questions Time Range Information Access and Dissemination Innovative formats and designs to reinvent topographic maps in an electronic environment 1. What is the widest range of scales that can be mapped only by adjusting map symbols combined with selectively removing feature types? Short term 2. What is the minimum amount of change to map symbols and content that provides the maximum scale range maintaining topographic map usability? Short term 3. What is the stability of topographic map design (with the goal of establishing a coherent set of designs that function from coarse to fine resolutions through scale change)? Short term 4. What should be the visual hierarchies for the base National Map layers? Short term 5. How should USGS select a subset of automated and manual approaches to visual hierarchies to provide a tool that effectively serves the largest number and variety of National Map users seeking to answer geographical questions that are not served by commercial point-to-point navigation tools (e.g., Google Maps, MapQuest, and Yahoo!)? Short term 6. What is the optimal combination of types and number of symbols for an inexperienced user to create an effective topographic map and accommodate a data overlay on a topic of interest using web tools? Short term
OCR for page 95
A Research Agenda for Geographic Information Science at the United States Geological Survey User-centered design for implementation of The National Map web services 1. With the goal of updating and evaluating The National Map viewer user interface, (a) what types of user interfaces are appropriate for The National Map viewers, (b) does The National Map need different viewers for different users and map contents or is a single one appropriate, and (c) what kinds of communication methods are effective for disseminating geospatial information through web browsers? Short term 2. Will new web mapping technologies, such as vector-compression algorithms, AJAX, and Adobe Flex, improve the usability and system performance of The National Map servers and general web mapping applications? Short term 3. What is an appropriate standardized user testing and evaluation method for assessing and improving the effectiveness of National Map products? Short term Open Geospatial Consortium (OGC) Standard Profiles for The National Map web mapping services and map layer design 1. How should USGS create OGC standard profiles (which are a subset of standard specifications and customized standard content) to bring layers in The National Map databases into conformance with OGC standards? Short term 2. How can USGS overlay well-positioned labels with clear categories and hierarchies on top of symbolized features dynamically set to foreground and background depending on user interests? Short term
OCR for page 96
A Research Agenda for Geographic Information Science at the United States Geological Survey Integration of Data from Multiple Sources Generalization 1. What are the specific new generalization operations and algorithms that will be needed for The National Map? Short term 2. What feature-based generalization is needed for The National Map (the focus would be on a specific feature, such as a stream, and approaches needed for stream generalization) and how can that be accomplished? Long term 3. What new kinds of measurements will be needed to determine locational conflicts between USGS features? Short term 4. What are the effective scale ranges for fusing two layers together, and how does generalization affect fusion? Long term Data fusion 1. What are the data quality issues related to spatial data integration and fusion? Short term 2. How can areal interpolation—as a key method for fusing aspatial data with spatial data—be applied in The National Map? Long term Data Models and Knowledge Organization Systems Geographic feature ontologies 1. What are the key sets of topographic features portrayed within The National Map layers that should be explicitly represented in ontologies (these might align with the set of features already identified within the Spatial Data Transfer Standard; USGS, 1994)? Short term 2. What are the formal operational definitions for these features, their parts and structures, and their relationships to other features? Short term 3. What automated feature extraction methods are derivable from these operational definitions? Short term
OCR for page 97
A Research Agenda for Geographic Information Science at the United States Geological Survey Ontology driven data models and gazetteers 1. How does a geographic feature ontology operationally support a National Map feature database? Long term 2. How can the collection, validation, modeling, and management of vernacular names be facilitated? Short term 3. How can the creation of more detailed or smart feature footprints be automated? Short term 4. How can the implications of fuzzy footprints in gazetteers be managed? Short term Quality-aware data models 1. How can sampling distributions of complex objects be defined and managed (e.g., reduce them to points in some N-dimensional shape space)? Long term Data models for time and change 1. What can be learned from spatiotemporal use cases for advancing spatiotemporal models for The National Map? Long term 2. How is change effectively represented in spatial data sets? Long term 3. How can process-based models be used to improve data quality or quality awareness in The National Map? Long term Transaction processing 1. What is the transaction processing logic for complex spatiotemporal transactions among National Map and other USGS databases? Long term
OCR for page 98
A Research Agenda for Geographic Information Science at the United States Geological Survey This page intentionally left blank.
Representative terms from entire chapter: