PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
January 2019
7
A N I N T E R V I E W
DR. DAVID F. MAUNE
Dr. David F. Maune served 30 years of Army
active duty as a commissioned officer in the
U.S. Army Corps of Engineers (USACE). He
specialized as a Topographic Engineer, last
serving as Commander and Director, U.S. Army
Topographic Engineering Center (TEC) – now
the Army Geospatial Center (AGC). Today
He is a Senior Project Manager for Dewberry
Engineers, Inc. and currently editing the 3
rd
edition of “Digital ElevationModel Technologies
and Applications: The DEM Users Manual.”
What did you learn from your active duty years in U.S. Army
Corps of Engineers (USACE)?
Nearly all engineers apply the principles of science and mathematics to
develop economical solutions to technical problems; their work is the link
between scientific discoveries and the commercial applications that meet
societal and consumer needs. Topographic engineers apply the princi-
ples of geodesy and various forms of remote sensing to map topographic
and bathymetric surfaces – also to satisfy societal and consumer needs.
During my Army years, most engineers in USACE built physical infra-
structure; but topographic engineers built geospatial infrastructure.
Tell us about your background that lead you to editing the
DEM Users Manuel?
I retired from Army active duty in 1991 and joined Dewberry in 1992
where I initially applied my expertise to floodplain mapping for FEMA;
fortunately, I was able to pioneer FEMA’s evaluation of lidar and IfSAR.
At the ASPRS annual conference in 2000, I published a paper entitled:
“Lidar and IfSAR: Pitfalls and Opportunities for our Future.” That paper
was so well received that the ASPRS Executive Board asked me to write
an ASPRS book on lidar and IfSAR. I replied that I would do so provided
I could also include other technologies including photogrammetry, bathy-
metric lidar and sonar, and write it with a focus on the needs of DEM us-
ers, whether the DEM pertained to topographic or bathymetric surfaces.
The 1st edition of “Digital Elevation Model Technologies and Appli-
cations: The DEM Users Manual” was published in 2001, and the 2nd
edition was published in 2007. Having almost no standard DEM prod-
ucts in those days, both editions included a User Requirements Menu for
which users could pick and choose from a large array of choices for eleva-
tion surface types, data model types, source data, vertical and horizon-
tal accuracy, accuracy testing and reporting, forms of hydro treatments,
horizontal and vertical datums, geoid models, units, data formats, and
metadata. Because technologies were immature, we had no nationwide
DEM standards, guidelines and specifications, other than the FEMA
guidelines that long served as a de facto lidar specification. My User
Requirements Menu unknowingly demonstrated our need for standard
products because all of these menu choices led to a broad assortment of
nonstandard DEM products that were often incompatible with adjoining
datasets.
DEM
Users
Manual
3
rd
Edition
A Preview
Chapter 1—Introduction to Digital Elevation Models
,
along with Appendix A (Acronyms) and Appendix B (Defini-
tions), establishes the DEM vocabulary and definitions for
various forms of elevation raster data, vector data, and point
data (including point clouds) so that data users and produc-
ers can agree on standardized terminology. It is important
that DEM users understand the concepts of mass points,
breaklines, and triangulated irregular networks (TINs), for ex-
ample, and how they are used to produce uniformly spaced
topographic and/or bathymetric DEMs. This chapter also
covers topographic and hydrologic surface modeling, e.g.,
hydro-flattening, hydro-enforcement and hydro-conditioning
with examples at Figures 1 through 6 (below), as well as el-
evation derivatives and 3D terrain visualization. Definitions
from this manual were also incorporated in the USGS Lidar
Base Specification.
Chapter 2—Vertical Datums
defines a vertical datum as a
reference surface representing zero height – whether heights
abovesealevel(withvarioustidaldatums),orthometricheights
(elevations) above the geoid with equal gravity potential (with
various vertical orthometric datums), or ellipsoid heights
above a mathematical ellipsoid that approximates the shape
of the Earth as obtained from air-, land- or sea-based GPS. It
is important that DEM users understand geoid undulations,
how all U.S. vertical datums of the future will be geoid based
vertical datums that result from the National Geodetic Sur-
vey’s Gravity for the Redefinition of the American Vertical Da-
tum GRAV-D) project, and how to transform from one vertical
