Surveying and Land Information Systems

Vol. 60, No. 4, December 2000

 

The Surveying Profession and Its Educational Challenge

Charles D. Ghilani

 

Over the years several articles have been written about requirements of licensure in surveying, the role of surveyors in the new technologies, and requirements for continuing education. This paper looks at the interrelationships of these topics in relation to the professional status of the surveying community, educational requirements, and licensing requirements. It then recommends actions that the profession can take in these areas.

 

How Surveyors View Their Journals

Willie Tan

 

A recent survey on how surveyors view their journals shows that the journals may be classified under different clusters, each targeting a different audience. Although quantitative journals tend to be highly regarded, general-purpose journals seem to score better on impact. Editors may wish to consider important issues such as peer review, having an international editorial board, appropriate choice of content, joining international publishing databases and other signals of journal quality.

 

Enhancing Landsat Thematic Mapper Imagery for Wetlands Mapping

Hesham El Monsef and Scot E. Smith

 

In this paper, satellite imagery from the Landsat Thematic Mapper (TM) was enhanced using the Forest Inventory Analysis System (FIAS) and a principal components analysis (PCA) for the purpose of mapping wetland areas in northern Florida. The enhancement procedure resulted in an increased ability to identify wetland areas and also increased ability to discriminate types of wetlands. This technique will be useful for mapping wetlands in regions where suitable aerial photography does not exist or where time and financial constraints require the use of satellite imagery instead of aerial photographs. The process does not yield results commensurate with aerial photography and is not meant to replace aerial photography. It could, however, be potentially useful in the NWI production process for the following reasons: (1) it can be used to identify areas where no change has occurred since the last NWI mapping, thus eliminating re-interpretation; (2) it provides a means to use satellite imagery for the NWI when improved satellite imagery such as the one-meter IKONOS become readily available; and (3) it provides a quality check on existing NWI maps.

 

Accuracy of Angular Measurement with Various Targets at Different Distances

Abdalla Elsadig Ali and Dafer Ali Algarni

 

Five commonly used survey targets were tested for angular measurement accuracy using various target-distance-theodolite combinations. The results show that for distances less than 300 m, the geodetic target, the steel nail, and the plumb bob string perform fairly equally. For distances more than that, all targets tend to converge to a common accuracy value. The results of this experiment are relevant to surveyors, civil engineers, and other field measuring scientists who are interested in creating and applying land or geographic information systems (LIS/GIS) that use cheap and simple measurement equipment to collect survey data.

 

Antiques Surface Reconstruction Using a Non-Contact Measurement Method

Yu-Min Chang and Dar-Yuan Chang

 

This paper proposes a new method for reconstructing the original surface of damaged antiques by combining a non-contact measurement system and numerical analysis techniques. First, a non-contact laser scanner is used to measure the points of a damaged antique. Second, the measurements are subjected to numerical analysis whose results are then used to construct a model of the entire surface of the measured antique. Using this computer-generated geometric model, antique artist workers then repair and reconstruct the original shape of the damaged antique.  In this paper we describe the reconstruction of a lotus seat to demonstrate the adequacy of the proposed method.

 

 

Integrating GPS with Dead Reckoning Sensors

Peter Cederholm

 

A vehicle positioning system comprising a GPS receiver, a digital compass, and an odometer was tested on a 2.8-km stretch in Aalborg, Denmark. The system, which merges observations from the three instruments using a Kalman filter, has an update rate of 1 Hz and is intended for use in both urban and rural areas. The filtered positions follow the traveled route closely. A simulation suggests that the system will work even when the GPS coverage is insufficient.

 

Meander Lines and Vertical Datums of Southeast Alaska

Malcolm A. Menzies

 

In September 1977, a technical paper titled “Meander Lines of Southeastern Alaska” was published in the ACSM Quarterly Journal on Surveying and Mapping.  In it, I outlined the procedure for surveying meander lines in general terms and described the State of Alaska’s selected accretion treatment and the “quiet title” action. Also discussed were the solutions the Department of Natural Resources and local platting authorities developed to deal with the isostatic rebound phenomenon peculiar to southeastern Alaska’s meander lines. This note, which reflects both changing times and changing emphasis, attempts to determine whether isostatic rebound remains to be a problem 25 years after the publication of the 1977 paper and 90 years after the first reporting, in 1911, of rising landmass and receding water level in the region.

 

 

The Unexpected Role of High-Resolution Satellite Imagery in Protecting  Marine Habitats

Brian Soliday

 

One of the most interesting things about working in the technology field is discovering new uses for an existing technology that may be startlingly different than the original purpose it was designed for. We have all heard stories from the medical field about how drugs developed to treat one ailment are later discovered to be a cure for some other more devastating illness. A good example of this is aspirin, which was hailed as the first effective pain reliever a century ago, but which scientists recently discovered can also be used as a highly effective treatment for heart disease, the most prevalent cause of death in the United States today. There are similar stories about technologies in other fields that turn out to have astonishing applications not imagined by the technology’s inventors.

I have seen the same process of discovery happen in my own field, as scientists and professionals find new and unexpected uses for high-resolution satellite imagery.