Surveying and Land Information Systems
Vol. 61, no. 2
Conversations
In the late 1950s Robert M. Hutchins and Mortimer J. Adler
edited Great Books of the Western World. They connected their 54 volumes with
the Bible and came up with a list of The Great Ideas. Their assumption was that
these great ideas would be discussed by various authors over many years, and
the authors did indeed have a "conversation" on these ideas.
What about surveyors and mappers? Can we turn to their texts
and look for a "conversation"? Not really; surveying and mapping
texts show the state of the art and/or set out a lesson plan for learning this
science or art of surveying and mapping. But it is journals such as this one,
which can sponsor a conversation among it readers. Let's look at some of our
recent issues.
In the March 2000 issue, we brought you some of the papers
presented at the Surveying and Mapping Educators Conference held in July 1999
at Purdue University. As expected, most articles dealt with programs and
progress at our universities and colleges. The issue included an article by
Joshua S. Greenfeld on "Surveyors and GIS-The professional and Educational
Challenges." He drew attention to the fact that surveyors did not seem to
be getting into GIS and he looked at the education that would be needed for
surveyors to get more involved in GIS.
In the December 2000 issue, Charles Ghilani wrote about
"The Surveying Profession and its Educational Challenge." He looked
at the interrelationships between licensure in surveying, surveyors and the new
technology, continuing education, the professional status of the surveying
community and educational requirements. He made the point that it is
"…long overdue for the surveying profession to re-embrace the dual
requirements of scholarship and apprenticeship for licensure."
The March 2001 was devoted mainly to the NCEES Model Law for
Surveying and included an article by Joshua Greenfeld on "The four-Year
degree-When the Future of a Profession is at Stake." This article was
addressed mainly to those who oppose the requirement of a four-year surveying
degree for entry into the surveying profession.
In this issue we include an article by Charles Ghilani on
"Recruiting and Marketing." Ghilani deals with the problems of
under-enrollment in surveying/geomatics programs around the country and he
looks at ways universities can go about eliminating this problem. Ghilani
suggests workshops by surveying faculty for high school teachers. Why not bring
surveying and mapping ideas to middle and high school students? In many schools
around the country elementary, middle and high school students are using GIS in
their curriculum.
A whole lot of educational issues will come up in the
future. Working Group 1 of the FIG (International Federation of Surveyors)
Commission 7 has come up with a publication called Cadastre 2014-A Vision for a
Future Cadastral System by Jòrg Kaufmann and Daniel Steudler. One of their
recommendations is that "the most important actions surveyors can and must
take is to understand that technology is changing the surveying profession. The
two basic aspects of the profession-the ability to locate objects in the
physical and legal worlds and the ability to represent these objects on a
map-are influenced to a considerable extent by developments in the fields of
electronics and information technology." Cadastre 2014 seems to be a
combination of an extrapolation of the MPC (Multi-Purpose Cadastre) and
"deep information" as expounded by John Fellerman. Cadastral
surveyors of the future may need to know much more about GIS and computer
science than they do now.
I am not claiming that we are discussing great ideas of the
western world in our journal, but we have begun to discuss some very important
issues that are related to the life and death of the surveying and mapping
profession. I invite our readers to help expand this discussion-write to us and
tell us what your thoughts are on these issues.
Joseph C. Loon
Joseph.Loon@mail.tamucc.edu
* * *
Recruiting and Marketing
Charles D. Ghilani
When compared to our sister programs in engineering, all
surveying/geomatics programs in the United States suffer from a common problem,
namely under-enrollment. No matter the size of the program, it is often true
that when tenured members of the faculty retire, the administration tries to
redirect the salaries of these positions into higher enrolled programs. Quite
frankly, this is good business practice. However, this trend causes a flux in
surveying education that leads to accreditation problems, quality of education
issues, and lack of stability in surveying education as a whole. This paper
explores some of the possible causes for continually low-enrolled
surveying/geomatics programs and suggests marketing strategies for programs to
consider. It will present a long-range marketing plan developed at Penn State
aimed at providing enrollment stability, as well as some recent efforts that
are proving to be successful. Finally, it will suggest strategies that
professional societies can do support the efforts of academia.
* * *
Mobile Mapping Technology: Ten Years Later
(Part One)
Dorota A. Grejner-Brzezinska
This paper reviews the evolution of mobile mapping systems
(MMS) since the early 1990s, focusing in particular on GPS/INS-supported direct
platform orientation (DPO) technology and currently achievable georeferencing
accuracy. The topic is presented in two parts: Part One concentrates on the MMS
concept evolution, with a special emphasis on the advancements in imaging and
navigation components and benefits that the technology has brought to the
mapping and GIS community. A short review of inertial navigation is presented,
with a focus on the integration of GPS with inertial navigation. The
operational aspects of MMS and examples of actual land-based and airborne
systems are presented as well. In Part Two (which is scheduled to be published
in the September 2001 issue of Surveying and Land Information Systems), the
concept of direct georeferencing is explained and compared with the traditional
aerotriangulation (AT) method of image geo-registration. In addition, examples
of currently attainable navigation performance are presented and conditions
under which this performance is achievable are discussed, as are future
prospects of MMS.
* * *
Airborne GPS-Photogrammetry Comes of Age
Peter Kuntu-Mensah and Raymond J. Hintz
The use of the global positioning system (GPS) to determine
relative positional data for ground control points in a photogrammetric block
adjustment is widely accepted and practiced. On the other hand, using GPS to
determine camera exposure positions (airborne GPS, also known as ABGPS)
drastically reduces, and possibly eliminates, the number of horizontal and
vertical control points needed in aerial triangulation. Given that control
point determination is a major time and cost component of any photogrammetric
project, it would appear that commercial companies would be quick to implement
GPS-derived exposure stations. Furthermore, control points are often on or near
roads, making their location by ground-based survey techniques dangerous. In
practice, the number of companies using ABGPS is extremely small, perhaps
because of the natural uneasiness with the new technology. This paper reports
the results of an empirical evaluation of the application of GPS-derived
exposure stations for aerial triangulation. The results of this research show
that airborne GPS is, indeed, practical and quite feasible with minimum or no
ground control. The high accuracy level of current GPS technology meets the
accuracy requirements of photogrammetric applications. The results of this
research may help resolve any ambivalence about the use of airborne GPS and
foster its application in everyday photogrammetric operations.
* * *
Least Squares Network Adjustments via QR Factorization
John Halleck
This is an introduction to orthogonal QR factorization
(using Given's rotations) as an alternative to normal equations for the least
squares solution of network adjustment problems. The main advantage of the
method is its greater numerical stability. When the ratio of redundant shots to
non-redundant shots is small, QR factorization also has lower operation counts.
In addition, QR factorization allows for efficient use of the underlying
sparsity of the design matrix and has better performance on computers with
paged memory.
* * *
USGS Sets Ambitious Goal for The National Map
What is ACSM's role?
Curt Sumner
As reported in the ACSM Government Affairs Update dated June
18, 2001, the U.S. Geological Survey (USGS) recently issued a draft report for
public comment regarding its plan to create The National Map. The vision noted
in the report's preface states "by the year 2010, working with partners,
we will provide the nation with current, accurate, and nationally consistent
basic spatial data, including digital data and derived topographic maps, and
deliver spatial information that is not more than seven days old."
Further in the preface it is stated that " The National
Map is proposed as a database of basic spatial data that will provide a
starting point for users to extend and enhance, and to which users could tie
additional data, to meet their business needs. USGS will provide the leadership
needed to develop and continually maintain these data through partnerships
among federal, state, local, and tribal governments, the private sector, other
organizations, and volunteers."
Advancing from a system that has historically taken years to
update its maps to one that will provide updated spatial information that is
not more than seven days old will be quite an accomplishment. It would be
foolhardy, to assert that it cannot happen. Although it may not happen,
advancements in the technologies that make such a vision even thinkable may
very well permit it. In fact, most of the technology needed is already
available.
On a recent visit to USGS headquarters in Reston, Virginia,
for their periodic open house, I was amazed to see some of the activities
taking place there. Being able to find on a computer, photographs of my
hometown in Virginia right down to my mom's house, and then getting a printout
of it, was pretty exciting. Standing before an electronic world map and
watching the sequence of volcanic eruptions over the past several decades take
place within a matter of minutes was awe inspiring. Even for one who, through
my work with ACSM, has seen a great deal of what is in this country, the
presentation of all of that information was very impressive. For the person
inside, who is still a small-time surveyor at heart, it made me feel pretty
insignificant. In retrospect, though, I see that all of that data and the
different applications for its use is no more than a compilation of the work of
many people just like me doing their part. It is with that view that I am writing
this article.
While The National Map concept envisioned by USGS is
difficult to grasp at first glance, it may very well be achievable. The
question that comes to mind is, "How, and for what purposes, will it be
used?" When the vision statement in the preface of the report speaks of
accuracy, people like surveyors get nervous. We are so accustomed to dealing
with extremely accurate data, it is difficult to accept that not all data needs
to be as accurate as that we use. At the same time, we know from experience
that those who do not understand the relativity of accuracy tend to think
anything depicted on an "official" map is "dead on," as we
surveyors say. This realization leads us to sometimes be leery of data
represented in a GIS. Because of our commitment to the public good, surveyors
worry about how people may be affected if they misinterpret the accuracy of
data in a GIS. As a practical matter,, The National Map will be a GIS. This
notwithstanding, surveyors must realize that there are many uses for GIS data
that do not require survey grade accuracy. Many ACSM members work in arenas
outside of the survey world, and play major roles in the development and
maintenance of GIS. A great deal of the data they use is not "survey"
data. What, then, is the role ACSM and its members can play in the inevitable
development of a national map, whether it is actually created by USGS or by
some private vendor who acts more quickly?
First, we need to express concerns we may have with the
concepts outlined in the USGS report. Comments sent to USGS from ACSM are
attached to this article. Secondly, we must remain aware of what is being done
in the map's development, and continue to be a part of the process, rather than
complain after it is too late for input. The ACSM Government Affairs Committee
and ACSM staff work very hard to keep abreast of all issues important to our
members, but there are not enough of them and they are not well enough funded
to get it all done alone. ACSM members need to be on the front lines, helping
with the development of standards and training the volunteers the USGS report
speaks about. We need to be actively involved in the agencies where we work, or
pursue work to be contracted to private firms as part of the project.
In summary, our role in this, or in any other project is to
become part of the process that determines what should be done, and how it
should be done, not to close our minds to the idea that it may be done.
COMMENTS REGARDING THE NATIONAL MAP
From
THE AMERICAN CONGRESS ON SURVEYING AND MAPPING, INC
The American Congress on Surveying and Mapping, Inc. (ACSM)
congratulates the USGS on its proposal for the development of The National Map.
Clearly, basic spatial data as described in the draft document, is important
for the current and future needs of the almost infinite user communities that
will evolve along with, and because of, the technologies that will help provide
the data.
ACSM appreciates the
opportunity to provide comments on the draft document. In keeping with the
suggestions for reviewers listed within the Invitation for Comments, the following comments from ACSM might be
characterized as "items that need to be clarified." For this reason,
we would like to meet with USGS to discuss further development of the plan and
its implementation.
Throughout the document there are numerous references to
data collection, the positional accuracy and completeness of data, and the
common referencing system on which data is based. ACSM contends that any data
collected should include metadata acknowledging how the data is collected and
to what standard of accuracy. This is a
critical element for any body of data, so that users will know what level of
confidence to place in it. Likewise, it is important to use a uniform datum for
expressing data positions. The most common datum utilized is geographic
coordinates (latitude and longtitude) that can be easily converted to state
plane coordinate system values. The National Spatial Reference System provides
a network of highly accurate horizontal and vertical reference points on which
positions should be based. Standards for data collection also help to eliminate
duplication and allow for multiple use of geographic data. ACSM would very much
like to assist USGS in developing these standards for The National Map.
Partnerships with the public are discussed on page 15 of the
document. This section proposes the use of a volunteer force predicated on the
"anticipated widespread availability of Global Positioning System (GPS)
capabilities in personal devices," and a training program for that force.
ACSM feels that further discussion of this concept is warranted with regard to
the anticipated accuracy of data collected and the potential end use of the
data. Liabilities associated with unintended, and even unauthorized, collection
and use of data such as that to be depicted on The National Map need to be
considered. In fact, some states have developed rules that outline what types
of GPS data collection must be conducted by
Licensed Professional Surveyors because of incorrect data provided by
well meaning individuals. ACSM can assist USGS in making the volunteer force
aware of these rules, and in training them.
Respectfully submitted for ACSM,
Curt Sumner, Executive Director