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##### DA-31 - GIS&T and Libraries, Archives, and Museums

Libraries, archives, and museums (LAMs) are an important part of the GIS&T ecosystem and they engage in numerous activities that are critical for students, researchers, and practitioners. Traditionally these organizations have been at the forefront of developing infrastructures and services that connect researchers and others to historical and contemporary GIS data, including print maps. More recently, as a result of greater interest in spatial thinking and research, these organizations and institutions have become a place for instruction, outreach, and practice. This entry will discuss the historical role that LAMs have played in supporting and developing GIS&T as well as focus on current trends.

##### AM-06 - Grid Operations and Map Algebra

Grid operations are manipulation and analytical computations performed on raster data. Map Algebra is a language for organizing and implementing grid operations in Geographic Information Systems (GIS) software, and is typically categorized into Local, Focal, and Zonal functions, where each function typically ingests one or more grids and outputs a new grid. The value of a specific grid cell in the output grid for Local functions is determined from the value(s) of the analogous cell position(s) in the input grid(s), for Focal functions from the grid cell values drawn from a neighborhood around the specific output grid cell, and for Zonal functions from a set of grid cells specified in a separate zone grid. Individual functions within a category vary by applying a different arithmetic, statistical, or other type of operator to the function. Map Algebra also includes Global and Block function categories. Grid operations can be categorized as data manipulation procedures or within domain-specific applications, such as terrain analysis or image processing. Grid operations are employed in a variety of GIS-based analyses, but are particularly widely used for suitability modeling and environmental analyses.

##### DA-18 - GIS&T and Disaster Management

Geographic Information Science and Technology (GIS&T) has a long-running tradition of using spatially-oriented methodologies and representational techniques such as cartography and mapping to address hazards and disasters. This tradition remains important as ever as global society faces newer and more complex challenges resulting from climate change and new challenges such as the COVID-19 pandemic. GIS&T has become an invisible technology within the disaster management cycle of planning and preparedness, response, recovery, and mitigation. Spatial technologies such as geographic information systems (GIS), remote sensing techniques, spatial data science, artificial intelligence, and machine learning are now widespread and pervasive. Despite these advancements, there is more that can be done to incorporate GIS&T perspectives into disaster management. In this article, we outline important conceptual ideas to consider on the use of GIS&T for disaster management, disaster management organizations that use GIS&T, and practical information to orient newcomers to this exciting and important interdisciplinary combination.

##### AM-40 - Areal Interpolation

Areal interpolation is the process of transforming spatial data from source zones with known values or attributes to target zones with unknown attributes. It generates estimates of source zone attributes over target zone areas. It aligns areal spatial data attributes over a single spatial framework (target zones) to overcome differences in areal reporting units due to historical boundary changes of reporting areas, integrating data from domains with different reporting conventions or in situations when spatially detailed information is not available. Fundamentally, it requires assumptions about how the target zone attribute relates to the source zones. Areal interpolation approaches can be grouped into two broad categories: methods that link target and source zones by their spatial properties (area to point, pycnophylactic and areal weighed interpolation) and methods that use ancillary or auxiliary information to control, inform, guide, and constrain the interpolation process (dasymetric, statistical, streetweighted and point-based interpolation). Additionally, there are new opportunities to use novel data sources to inform areal interpolation arising from the many new forms of spatial data supported by ubiquitous web- and GPS-enabled technologies including social media, PoI check-ins, spatial data portals (e.g for crime, house sales, microblogging sites) and collaborative mapping activities (e.g. OpenStreetMap).

##### DA-08 - GIS&T and Archaeology

Figure 1.  USGS topo map and bare earth (LiDAR) image of Tennessee’s Mound Bottom State Archaeological Area. Bare Earth DEM processed by Zada Law.

Archaeology provides a glimpse into the lives of past peoples and histories that may have otherwise been forgotten. Geographic Information Systems and Technology (GIS&T) has become an invaluable tool in this endeavor by advancing the identification, documentation, and study of archaeological resources. Large scale mapping techniques have increased the efficiency of site surveys even in challenging environments. GIS&T refers to such things as remote sensing, spatial analysis, and mapping tools. The use of GIS&T for archaeology is a truly interdisciplinary field as it borrows principles from geology, oceanography, botany, meteorology and more in order to further the science. This chapter discusses some of the primary GIS&T tools and techniques used in archaeology and the primary ways in which they are applied.

##### DA-33 - GIS&T in Urban and Regional Planning

Professionals within the urban and regional planning domain have long utilized GIS&T to better understand cities through mapping urban data, representing new proposals, and conducting modeling and analysis to help address urban problems. These activities include spatial data collection and management, cartography, and a variety of applied spatial analysis techniques. Urban and regional planning has developed the sub-fields of planning support systems and Geodesign, both of which describe a combination of technologies and methods to incorporate GIS&T into collaborative planning contexts. In the coming years, shifting patterns of global urbanization, smart cities, and urban big data present emerging opportunities and challenges for urban planning professionals.

##### DA-32 - GIS&T and Natural Resource Management

Geographic Information Systems (GIS) is a geospatial technology that has matured with the help of natural resource management applications. Since its early beginnings as an extension of cartography, GIS has been used to capture, manipulate, store, analyze and manage data. GIS has matured as additional sciences began to adopt and apply it to multidisciplinary problems. In the mid-90s, much of the emphasis moved to desktop GIS making the access and use more mainstream and capable on personal desktop computers. Government agencies with more available and distributed datasets through the internet enabled more applications and use across disciplines because of the access. Soil scientists, wildlife biologists, hydrologists, engineers, planners, and others could now pursue spatial problems efficiently and effectively. More and more advances were being made in the sciences due to the new technology. The following discussion will focus on the use and applications of GIS for natural resource management. Areas covered in this review will be for forestry, watershed analysis, wildlife management, and landscape analysis. First a background of the applications will be introduced followed by a discussion of their applicability and uses.

##### DA-13 - GIS&T in Criminal Justice and Law Enforcement

Linking crime and place has been the objective of crime mapping since the early nineteenth century. Contemporary scholars have since investigated spatio-temporal crime patterns to explain why crime concentrates in certain places during certain times. Collectively, this body of research has identified various environmental and situational factors that contribute to the formation of crime hot spots and spawned widespread crime prevention and reduction strategies commonly referred to as place-based policing.  Environmental criminology guides the bulk of this crime-and-place research and provides a means for interpreting place and crime. The chapter details theories behind place-based policing, examples of place-based policing strategies that leverage geographic information science and its associated technologies (GIS&T), and relevant data visualization tools used by law enforcement to implement place-based strategies to address crime.

##### AM-09 - Classification and Clustering

Classification and clustering are often confused with each other, or used interchangeably. Clustering and classification are distinguished by whether the number and type of classes are known beforehand (classification), or if they are learned from the data (clustering). The overarching goal of classification and clustering is to place observations into groups that share similar characteristics while maximizing the separation of the groups that are dissimilar to each other. Clusters are found in environmental and social applications, and classification is a common way of organizing information. Both are used in many areas of GIS including spatial cluster detection, remote sensing classification, cartography, and spatial analysis. Cartographic classification methods present a simplified way to examine some classification and clustering methods, and these will be explored in more depth with example applications.

##### DA-05 - GIS&T and Local Government

GIS is an important tool for local governments. It is utilized to provide spatial information, metrics, and visualizations to constituents, businesses, and decision-makers. Internally, a well-managed GIS can be the basis for innovation and process improvement and can be a single source for employees to find a plethora of integrated data. This entry discusses how GIS supports local government, important considerations for maintaining a successful local government GIS, and current trends. This entry is based on the author’s experience in a GIS program at a medium-sized city in the Rocky Mountain Region of the United States. Not everything discussed may apply to other areas of the country or world. Additionally, smaller-sized programs may not have the resources to implement everything discussed. The key purpose of this entry is to provide students and instructors with tangible examples of processes, skills, and organizational structures that make for an effective local government GIS.