SaLIS June 2007

VOL. 67, NO. 2)

 

Editorial Latitudes

Steve Frank Steve Frank, New Mexico State University

sfrank@nmsu.edu

 

This is my first issue as editor of Surveying and Land Information Science (SaLIS).  While I have edited several special issues of the journal, I note some differences.  First, special issues are a lot easier!  They comprise collected and/or solicited papers from a conference or an event organized or for a specific purpose.  Those issues almost edit themselves.  In my new role I find that I am still soliciting papers, still looking for special editions.. I’m looking for those quality papers that make a quality journal, and the quality people who can review the papers, and so ensure that we are upholding that quality.  Only now I am doing this as a part of my regular activities.

 

I am fortunate to know many people in the surveying and mapping fields to whom I can turn to not only for papers, but also to help me review  submitted papers  from the technical viewpoint—an important step in insuring the quality of the information presented.  I am well aware that not every article we publish will be of interest to all readers or to everyone’s liking, but SaLIS is a journal serving many interests in the geospatial community, with one goal—to advance our knowledge in surveying and mapping.

 

I think that we have a good selection of articles in this issue. Said Easa revisits the 3D resection problem and proposes an alternate method to solving this problem. Michael Barry explores boundary surveying in Capetown, South Africa, touching on the politics involved as that country after it emerged from the apartheid era. Kurt Wurm writes about the BLM Global Coordinate Database (GCDB) project and how to improve initial values within the system, along with the results of the tests performed to do so.  Chryssy Potsiou reports on the International Federation of Surveyors (FIG) Commission 3 activities, and we have a student paper on boundary surveying submitted by Professor James C. Crossfield, California State University at Fresno.  We hope to feature other well written student papers in future issues, including papers from the NSPS Student Competition. Also included are a book review and a literate review.

 

That this issue is late is a matter of concern to me and to the managing editor. While we cannot fix the problem overnight, we are working to close the gap between issues and get back on track in the near future. We realize that for any journal to be in the top tier in its field, it not only has to publish papers of the highest quality; it has to be on time as well. Indeed, one of my personal goals is to transform, with the help of many others, the journal into a source of that scientific knowledge that informs many of the surveying and mapping solutions currently on the market.   

Inclosing with my first remarks, I would like to thank AAGS, GLIS and NSPS for giving me this opportunity to work with the journal.  I would like to thank the previous editor, Joe Loon, for helping me transition into my new role as the SaLIS editor. I would like to thank Ilse Genovese, our managing editor, who keeps me up to speed and remembers all the things that I forget.  This is our opportunity to share knowledge and learning not only within our respective organizations, but with the world-wide surveying and mapping community.  I hope to enjoy many years working with you.  

 

Direct Distance-based Positioning without Redundancy—In Land Surveying

Said M. Easa

In land surveying, distance-based 3D positioning involves observing distances to (or from) three stations with known positions. Because the resulting problem is nonlinear, the solution is normally found using an iterative method that requires initial approximate values of the unknown position. This paper introduces a direct (non-iterative) distance-based method for 3D positioning in land surveying. Error propagation analysis was performed to evaluate the stability of the method. In addition, a similar direct method for 2D positioning is presented. The application of the methods is illustrated using several numerical examples. The presented methods could best be utilized in surveying practice to programmatically determine the best initial values prior to the iterative solution with or without redundant observations.

KEYWORDS: Positioning, resection, intersection, distance, land surveying, direct solution, three-dimensional, error propagation

 

 

Boundary Systems in Post Apartheid Urban Settlements in Cape Town

Michael Barry

In the four-year period of negotiations leading up to the first fully democratic elections in 1994 which set in motion South Africa’s transformation from the apartheid system to a nonracial democracy, land and housing were major issues in the many discussions surrounding what the new country should look like. Access to land for the previously disadvantaged, land restitution claims, and redistribution of land to reflect the demographic profile of the country featured prominently in these debates. Land tenure types and boundary systems were important issues for land surveyors at the time. Boundary proposals included fixed boundaries, general boundaries, fixed boundaries for block corners with general boundaries internal to a block, and a midpoint cadastre where dwellings were referenced to a single monument. Based on four cases studied over fourteen years in the Cape Town area, the existing system of fixed boundaries is considered appropriate. However, the manner in which land is delivered and boundaries are managed could be improved to reduce the level of conflict over boundary encroachments, and the studies provide lessons for other post-conflict situations. Although this may be difficult in violent conflict situations, it is also important that grassroots opinions on desired land tenure types and the manner in which they are formalized and symbolized are solicited when formalizing strategies for managing land tenure in a post-conflict society.

 

KEYWORDS: Fixed and general boundaries, communal blocks, informal settlement upgrades, participatory development

 

 

An Assessment of the Upgradable Spatial Accuracy of the Geographic Coordinate Data Base

Kurt Wurm

The accuracy of the Geographic Coordinate database (GCDB) is best understood through an understanding of the collection procedures and data sources. The rigorous analysis used to create the spatial data representing the township provides us with coordinate positions and an estimate of uncertainty in those coordinates for corners of the U.S. Public Lands Survey System (PLSS). Recently a project has been undertaken at the New Mexico State University (NMSU) which involved an extensive PLSS retracement. This article discusses the findings of this survey and will illustrate the dynamic nature of the GCDB design which has ability to be updated over time as a key design element.

 

 

Joint FIG Commission 3

UN/ECE Working Party on Land Administration, UN/ECE Committee on Housing and Land Management

Workshop on “Spatial Information Management toward Legalizing Informal Urban Development” and “Informal Settlements—Real Estate Market Needs for Good Land Administration and Planning”

Chryssy Potsiou

This was the first FIG Com3 annual workshop and meeting in a series of three planned for the new term 2007-2010. The next joint FIG Com3 and UNECE Committee on Housing and Land Management Workshop (as a follow up) is planned to be held between 18-21 February 2008 in Valencia, Spain, under the topic: “Spatial Information Management Toward Environmental Management of Mega Cities”. More detailed information will be published soon.

 

A Perspective on Boundary Surveying Articles

James K. Crossfield

 

I began attending national ACSM meetings in the spring of 1977. I was awe struck by the sheer intensity and size of that exciting experience. The fall 1997 meeting was in Little Rock Arkansas. A play-de-do cocktail at Andersons Wharf was particularly memorable. I attended the sessions with intensity to learn as much as possible. One particular talk was about a boundary problem that a surveyor had faced. Later, while working at the University of Arkansas in Fayetteville and sharing an office with Dave Knowles, I remembered that talk and sought out the speaker for a copy of the paper (it had not been in the proceedings). I knew the speaker had something written down because he was shuffling papers while he spoke. But I never got a response. Why? Reading Surveying and Mapping (the precursor of Surveying and Land Information Science (SaLIS)) I noticed that there had been a few articles about boundary issues and the public land surveys into the late 1970s, but by the eighties, such articles were few and far between. One of my few editorials as Chair of the SALIS Editorial Board stated that “Land surveyors are especially encouraged to submit articles discussing boundary surveys, with special emphasis on the legal issues involved or illustrated” (SALIS Vol. 50 No. 1 (March 1990), p.3). Few heeded this request. Why?

 

One may conjure up several possible answers to these two questions. There is no need to list them all here. Perhaps the most plausible explanation is that surveyors are so busy (and probably so tired from overwork) that they are physically unable to write legal articles for professional journals. But there is a need for boundary issues to be discussed and written up because that is how a profession stays current and grows intellectually. Because surveyors do not often write about their work for professional journals, perhaps people who will become surveyors (students) might do so instead.

 

Surveying students at California State University, Fresno, have been required to write legal boundary papers since 1989. Since then, nearly 300 students have each written a mandatory paper about boundary control legal principles. Each student is required to develop a hypothesis (what they intend to prove) and use case law, journal articles, and reference books as references. While many of these papers over the years have been exceptionally good, one recent example, by Chase Miller, is provided in this issue. Miller’s paper proves that the physical monument controls over distances and bearings.

 

In future articles, Jacquiline Luk suggests that maps and plats do not have legal priority over surveys and field notes in determining boundaries. John Gletne demonstrates that the riparian boundary changes as the extent of an adjacent water boundary moves, but that land lost or gained by avulsion results in no riparian boundary changes. Joshua Ford states that adverse possession may sometimes be claimed against lands that are vested in the United States. Marshall Fargen tries to clarify how land that has been entirely lost due to long-term inundation is vested.

 

Professional land surveyors are urged to read these articles. If you think there are omissions, or issues raised, then write up a comment and submit it to the SaLIS editor, Dr. Steve Frank. Perhaps some professional dialog will be initiated. That would be good for the profession.

 

Monuments vs. Distance and Direction

Chase Miller

Natural and artificial monuments control over distance and direction. A natural monument is less easily disturbed and controls over an artificial monument. A monument must be a locatable point whose location is identifiable enough that I won’t be debated. A monument reveals the original surveyor’s intention of where the point should be. Given distances and directions are intended to guide a surveyor to the monuments. No geomatics measurement is exact. Uncalled monuments should not control a survey unless their location in relations to the survey can be proven. An obliterated monument’s identified location still controls the survey. 

 

Book Review

Adjustment Computations: Spatial Data Analysis, 4th ed., by Charles D. Ghilani and Paul R. Wolf, John Wiley & Sons, Inc. ISBN-13 978-0-471-69728-2; ISBN-10 0-471-69728-1, 611 p, CD.   Reviewed by Ernie Cantu.

 

With the commonplace occurrence of computers in the workplace, the least squares method of adjusting survey measurements is gaining popularity as the best method with the most rigorous adjustment procedure available. It is this very idea that is the overriding concept throughout the fourth edition of Adjustment Computations: Spatial Data Analysis by Charles D. Ghilani and Paul R. Wolf. This text book ranks as a superior choice for students preparing for licensing exams, for professionals in surveying, photogrammetry, GIS fields, and for urban planners, geographers, and transportation planners—in other words, anyone looking to obtain the skills of adjusting survey data. Whether the reader pursues that goal through personal studies or through a college course in Adjustment Computations, this book is an excellent choice for education, and it is available at local bookstores or by calling 1-800-225-5945. In Canada, call 1-800-567-4797.

 

 

Review of Recent Literature

Compiled by Mike & Mary Craymer

Editors’ Note: This is a collection of selected articles on geodesy, surveying and land information systems published in English in other subject-related journals. This information has been compiled from Tables of Contents in Geodesy, a free Internet-based contents service for journals in geodesy. Because of space constraints, coverage may not be complete for all journals. For more complete coverage and information about TCG, article reprints and journal publishers, visit the TCG web site at http://www.craymer.com/tcg/