National Center for Geographic Information and Analysis

Download this index for direct links to 122 technical reports in the NCGIA Technical Papers series, published in the 1988-1997 period.

Spherekit is a spatial interpolation software toolkit developed at NCGIA as part of Initiative 15: Multiple Roles of GIS in U.S. Global Change Research. This package features several unique capabilities and is freely distributed over the internet. Spherekit allows interpolation over continental or global scales by computing distances and orientations (among data and interpolation points) from geodesics on the surface of the globe. Conventional interpolations typically are based upon Euclidean distance in Cartesian 2-space which involve planar projections that produce distortions of some kind. In Spherekit, projections are applied only for display purposes after the interpolation has been carried out using spherical geometry. Users can select from several interpolation algorithms that have been adapted to the sphere: inverse distance weighting, thin plate splines, multiquadrics, triangulation, and kriging. Spherekit enables the user to incorporate knowledge or information about the processes that produce the underlying spatial variations into the interpolation model. A built-in equation editor and a collection of nonlinear transforms allow the user to create and experiment with new, physically meaningful variables from the independent and dependent variables available. 

This report is a reference guide to the software and is not intended to be read from cover to cover. Chapter 2 presents four examples of the use of the software. Chapter 3 takes a single example and presents the steps required to carry out an interpolation. Chapter 4 describes each of the menu options available in Spherekit. Chapter 5 provides a technical description of the interpolation algorithms. Finally, Chapter 6 describes the download and installation procedures.

This paper reports the discussions and key findings of a three day workshop held in Gävle, Sweden immediately prior to the 18th ICA/ACI International Cartographic Conference in Stock- holm. The workshop mirrored the considerable success of the first workshop help in Barcelona in 1995 and comprised demonstrations, presentations, and parallel sessions. Thirty nine delegates came from seventeen countries comprising 20% from National Mapping Agencies (NMAs), 10% from the private sector and 70% from research institutions (Geography, Cartography, Surveying, Computer Science, Physics, Planning and Linguistics). The objective of the workshop was to hold a series of discussions focused on impediments to automated map generalization, the current state of knowledge, and progress on specific problem areas. Whenever possible, discussion pressed to define specific areas for research in the coming two years. These will be noted throughout the report.

This report is structured around the plenary session headings, includes a summary of one session held jointly with the ICA Visualization group meeting concurrently in Gävle, and concludes by listing the intended themes for discussion at the next workshop in 1999.

This report describes the outcome of the Specialist Meeting of the NCGIA Research Initiative 21 on "Formal Models of Commonsense Geographic Worlds". The meeting was held in San Marcos, TX on October 30- November 3, 1996.

Research Initiative 21 is concerned with the development of formal models of commonsense geographic worlds. Discussions at the Specialist Meeting focused on the commonsense or naive geographic reasoning that people perform and whose outcome makes intuitive sense to most people. The Specialist Meeting brought together specialists from geographic information science, artificial intelligence, computer science, geography, developmental psychology, and behavioral science to foster discussions leading towards a better understanding of the nature of naive geographic reasoning and how better to incorporate naive geographic knowledge and reasoning into GIS.

This Report serves to document the discussions held during the meeting and, most importantly, delivers a set of researchable questions that forms the basis for future research in this area. Participants collected close to 50 questions worthy of further consideration and research on topics relating to the fundamentals of Naive Geography, developmental influences on Naive Geography, and the impact of Naive Geography on GIS.

This bibliography attempts to bring together literature covering the many aspects of Multipurpose Land Information Systems (MPLIS) development. Our focus on MPLIS development comes from a concern that much of GIS adoption and diffusion research focuses on a single system within an organization instead of a network of resources within the context of a larger community. We have worked to broaden the view of MPLIS development to include the processes commonly referred to as initiation, implementation, operation and maintenance.

To reflect these issues, we have attempted to develop a bibliography that includes: (a) the concept of the community-wide value of MPLIS development and the products of these systems, (b) developmental factors and techniques, (c) studies of system status, and (d) the MPLIS development process or the adoption and diffusion of innovations and related technologies. A brief explanation of each of these topics is provided along with specific examples from the bibliography.

Behavior of geographic objects holds a critical role in spatial databases. This, along with objects’ position and space-varying attributes, form a minimal set of concepts sufficient to capture spatialpeculiarities in terms of the object-oriented rational. This paper presents the semantics and the graphical notation of a prototypical object-oriented model for the conceptual design of spatial databases: by extending the Object Model of the Object Modeling Technique to the Geographic ObjectModel, we show how the above three concepts fit naturally into any object-oriented tool. We augment this model with the constructs of spatial aggregation and spatial grouping to express the critical aspects of space-varying attributes, object boundary fuzziness and uncertainty, spatial relationships, and attribute generalization. Our proposal integrates the field- and object-based geographic views in one model. The principal idea behind this effort is the incorporation of a set of concepts into any semantic or object-oriented model, to make them communicate at the conceptual level (semantic interoperability).

The objective of this thesis is the design of a spatial theory for GIS (consisting of representation, meta data, and transformations) that allows complete integration of data sets that differ in resolution and format. The scope is limited to a discrete view of geographic reality similar to "area-class maps", "categorical coverages", and "nominal fields". The spatial theory consists of representations of resolution-limited spatial knowledge, meta data that describe the knowledge content of representations, and transformations between representations of different type, resolution, format (raster or vector).

The spatial theory addresses the following problems: (1) What limitations does limited resolution impose on spatial knowledge that is represented in GIS? (2) How can such resolution-limited knowledge be represented in a way that keeps precise track of the contained spatial knowledge and its limitations? (3) How can the same spatial knowledge be represented in different formats such as raster and vector? (4) How can spatial knowledge be transformed to other representation types, levels of resolution, and formats? The viability of the proposed spatial theory is shown by demonstrating the implementability of representations and transformations. The practical applicability of the proposed resolution concept is shown by relating it to the resolution of sensors and by showing that resolution-limited representations can always be visualized within the limitations of display media.

In 1990, the NCGIA published the 1000+ page set of lecture notes, the NCGIA Core Curriculum in GIS (Goodchild and Kemp 1990). To support the lecture materials contained in the original Curriculum, in 1991 we published a pair of Technical Reports (Dodson 1991, and Veregin 1991) containing the laboratory exercises developed and taught in the Introductory GIS course in the Department of Geography at the University of California, Santa Barbara (UCSB). Since that time, the hardware, software and theory have changed dramatically and it has become necessary to revise these laboratory materials to keep up with these changes. In 1995, the Office of Instructional Development at the University of California provided funds to undertake this major revision. 

This document, then, is the second edition of GIS Laboratory Exercises: Volume 1. Labs 2 to 4 in this new set of exercises draw heavily on the original materials and data, though the text and questions have been revised to be completed using Idrisi for Windows. Labs 5 to 7 are completely redesigned to take advantage of the more user friendly features and practice datasets of ArcView 2. An instructor’s guide is available to accompany these materials.

This report seeks to provide a framework for Geographic Information System (GIS) based education module development. The full potential of GIS in the K-12 classroom has not been met in part due to the limited availability of necessary support materials such as tutorials, exercises, datasets, background information on GIS and geographical data, and packaged approaches to using GIS software in learning. Now, however, GIS software is becoming easier to use as it adopts point-and-click icon and menu-based graphical user interfaces in step with broader trends in computing. These positive trends have made creating materials that support teachers and students in their use of GIS more feasible and have encouraged various groups and individuals to begin creating these support tools.

The modules investigated in this report are all based on the Environmental Systems Research Institute (ESRI) software package ArcView 2. The focus is primarily on a series of educational modules developed over the past two years by NCGIA. The three modules are: Color Your World, the introductory module, which uses a global level dataset; Light Up Your Nation which uses national level nighttime space imagery; and Know Your Neighborhood which uses local level street network and demographic data. The experience of creating these materials is compared to three other ArcView module development efforts. We begin with a bit of background on the issues related to ArcView-based module development. This includes a discussion of the critical issues, both in the design and in the actual development process. Finally, we present a discussion of lessons learned from all of these efforts.

In this report, the creation of a digital, spatially referenced database of managed areas in the conterminous United States is described. A Geographic Information System (GIS) was used for database compilation to provide a high degree of flexibility for updates, queries, and manipulations. As concern over the degradation of ecosystems increases, so does the need for information about the spatial location and aerial extent of managed and protected areas. Recently, focus on the ecological issues of environmental preservation has been shifting from protection of individual endangered or sensitive species to protection of entire interrelated ecosystems. To meet the demands of studies in this area, datasets for large areas of land must be created and/or compiled. Guidelines and methods for creating these types of large datasets must also be established; currently there is little information of this type available. These factors were the motivation for the creation of this Managed Areas Database (MAD). This database contains all types of managed areas existing in the conterminous United States, including land held by federal, state, tribal, and private agencies and organizations. This large number of public agencies with land holdings and the numerous area designations makes the task of gathering and integrating managed areas data difficult and time consuming. MAD was developed at an approximate map scale of 1:2,000,000, with a Minimum Mapping Unit (MMU) of about 100 hectares. A number of digital and hard copy map sources were employed in compilation of this database. The database is divided into two separate GIS coverages. The first is a data layer containing polygons showing the boundaries of managed areas. The second is a layer containing data points which represent managed areas that are not large enough to meet the MMU requirements for the polygon coverage. Point coverage data may be less useful in some studies, however, it was felt that including all managed areas from the available map sources would produce a more complete database.

This technical summary document describes both the methodology employed and problems encountered in creating this managed areas database. In this document, we describe attributes available in the database, map sources used for compilation, classification of managed areas, integration of map sources, and possible sources of error. This managed areas GIS database can be combined with other information layers such as species and ecosystem distribution to allow comparison of administrative and ecological boundaries which may or may not coincide. Researchers will also be able to begin assessing the degree of protection given certain species or ecosystems at regional or national scales, and this database may someday be part of a much needed global coverage of managed areas.