PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
April 2014
289
Introduction
Soil survey investigations and inventories form the scientific
basis for a wide spectrum of agronomic and environmen-
tal management programs. Soil data and information help
formulate resource conservation policies of federal, state,
and local governments that seek to sustain our agricultural
production system while enhancing environmental quality
on both public and private lands. The dual challenges of in-
creasing agricultural production and ensuring environmental
integrity require electronically available soil inventory data
with both spatial and attribute quality. Meeting this soci-
etal need in part depends on development and evaluation
of new methods for updating and maintaining soil inven-
tories for sophisticated applications, and implementing an
effective framework to conceptualize and communicate tacit
knowledge from soil scientists to numerous stakeholders.
Remotely sensed data, initially in the form of analog,
unrectified panchromatic aerial photographs, became a pri-
mary soil survey technique in the early mid-20th century
(Bushnell, 1932; Millar, 1932; Buckhannan, 1939). This im-
agery provided a synoptic view of landscapes critical for in-
tegrating soil landscape patterns with observable or measur-
able soil properties that can vary in both space and time. Use
of digital imaging and associated geospatial information for
characterizing and mapping soils is expanding rapidly with
the advent of new sensors, aircraft and satellite platforms,
orthorectification techniques, mathematical models for inte-
grating disparate spatial data sources, and visualization of
soil properties using conventional and web-enabled technolo-
gies (Mulders, 1987; Barnes et al., 2003; Mulder et al., 2011).
Fusion of spectra from disparate sensors with terrain
derivatives from digital elevation models, soil geograph-
ic data, geostatistical predictions, and field observations
provides a powerful toolset for understanding soil systems
and mapping both static and dynamic properties in com-
plex landscapes and under intensive land use practices.
Recent advances in digital soil mapping (DSM) provide the
framework for applying effectively advanced imaging and
geospatial tools to produce input on soil properties and en-
vironmental co-variates. These data form the core of a soil
inference system used to predict and map soil properties,
estimate uncertainties of spatial prediction models, and
provide input to soil management programs (Boettinger et
al., 2010; Grunwald et al., 2011; McBratney et al., 2003).
The next generation of imaging and telecommunica-
tions systems integrated with complex analytical methods
and computing technologies will revolutionize the way we
inventory and manage soil resources across a wide range
of scientific disciplines and application domains (Omuto
et al., 2013; Herrick et al. 2013). Papers in this special
issue highlight some of those systems and methods for
the direct benefit of environmental professionals and stu-
dents who focus on imaging and geospatial information for
improved understanding, management, and monitoring
of soil resources. Five key emergent geospatial technolo-
gies not addressed in the special issue papers are profiled
here: airborne topographic lidar, proximal sensing of soil
properties, unmanned aerial systems (UAS), active and
passive microwave sensing of soil moisture, and web-en-
abled soil database access, computing, and mapping.
Airborne Topographic Lidar for Characterizing
Terrestrial Surface Features
L
ight
D
etection
A
nd
R
anging (lidar) is an emerging geo-
spatial technology that is improving our characterization
of terrestrial landscapes. Advantages over other forms of
remotely sensed data include spatial data collected in 3D,
geo-referenced during acquisition, and ability to classify
3D elements within point clouds into user-defined surface
features and above-surface features (Renslow, 2012). Im-
proved representations of the Earth’s surface, surface feature
structure, and reflectance intensity allow broad use of lidar
technology for mapping terrain derivatives and landscape
conditions critical for soil investigations. High horizontal
and vertical accuracy allow mapping of terrain features that
contribute to our knowledge of soil properties and dynamic
processes across multiple scales. At a suitable resolution,
lidar helps identify subtle topographic controls on soil vari-
Eme r gen t Imag i ng and
Geospa t i a l Techno l og i e s
f o r So i l I n ve s t i ga t i ons
S t ephen D . DeG l o r i a , Dy l an E . Beaude t t e , Jame s R . I r ons ,
Zami r L i bohova , Pegg y E . O ’ Ne i l l , Ph i l l i p R . Owens ,
Ph i l i p J . Schoenebe r ge r, La r r y T. We s t , & Doug l as A . Wysock i
