Peer Reviewed Articles
564 The Impact of Interoperable Geoprocessing
Lance McKee
567 Interoperable Web-Based Services for Digital Orthophoto
Imagery
John D. Evans
Abstract
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Disseminating digital geospatial imagery using an online service
makes it accessible to a wide audience by automating
such tasks as image selection, extraction, mosaicking, and
georeferencing. One such service, online for over two years,
has a streamlined, modular architecture, with a simple query
interface that facilitates its integration into a larger computing
context. This prototype illustrates how interoperable interfaces
may link online services into a global, seamless
infrastructure that will provide ortho-imagery and related
geospatial information to any client on demand.
573 Interoperable Spatial Data Catalogs
Douglas Nebert
Abstract
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The discovery of spatial information on the Web is challenged by the many approaches to organizing and presenting
it for search. Conventions for searching or navigating collections
of information on the Web are almost as personal and
unique as the Web authors who create them. Because there
are few rules in the creation of Internet information sites,
and because the number of these sites is increasing exponentially,
the discovery of specialized, highly structured information
- such as spatial information - is especially difficult.
Communities that require or generate imagery, cartographic,
and thematic spatial data usually manage their information
in highly structured ways, but the organizing structures are
not standardized. Inventories whose descriptive content is
dynamic are often stored in a database, opaque to systematic
web crawler searches. The use of full-text search engines
and, even more recently, 'meta" tags of keywords inside
HTML (HyperText Markup Language) documents often falls
short of imparting the contents of spatial data collections.
The OpenGIS Consortium (OGC) is in the process of defining implementable, interoperable spatial data catalogs that can be used to discover spatial data holdings in different data computing environments and across and within information communities. Spatial data catalogs have been around for many years, exemplified by product-specific image catalogs managed by remote sensing organizations. Unfortunately, there is little interoperability among spatial data catalogs, requiring the user or agent to traverse and translate many different user interfaces to locate relevant spatial data. In a broadly interoperble environment,a network of generic clients and servers could be built to enable global discovery of spatial data. As high-level software interfaces are standardized across disparate spatial data collections, access to them may be provided through reasonably lightweight gateway software. building up super-collections across and within information communities defied by discipline, geography, or cross-discipline interests.
577 Defining Standard Interfaces for Image Exploitation Services
Arliss Whiteside
Abstract
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The current effort in the Open GIS Consortium,lnc. (OGC) to
develop open specifications for a set of software interfaces
that enable diverse geoprocessing systems to access each
other's image exploitation functions and image data is described.
The objective is to specify standard interfaces to the
functions needed for both use and production of data. Developing
the Abstract Model of these services is the task of the
OGC Technical committee's Image Exploitation Services Special
Interest Group (IES SIG). The specification will become
part of OGC's OpenGIS Specification, which is intended to
address software and data interoperability in every kind of
geoprocessing, including GIS, photogrammetry, remote sensing,
digital cartography, and others.
585 The OpenGIS Data Model
John R. Herring
Abstract
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The OpenGIS Consortium (OGC) develops implementation
specifications to promote the interoperability of geographic
information applications. This development is based on the
concept of a comprehensive set of common software interfaces
supported by geographic servers, across computing
platforms. It has begun the process of making geographic information
and services an easily used technical information
resource. In the process, it is redefining the way many industries
look at geographic information.
589 Dynamic Monitoring with Video Systems
C.K. Lee and W. Faig
Abstract
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While close-range photogrammetry has been widely applied
for static deformation analysis, video cameras have many
characteristics that make them the sensors of choice for dynamic
analysis of rapidly changing situations. They also
have limitations.
This paper explores the potential of a video system for monitoring dynamic objects. The system consists of two camcorders, a VCR, and a PC with frame grabber. Basic characteristics of the video camera and frame grabber were investigated in static and dynamic modes. Then, sequential images of a moving car were captured and digitized at one-fifteenth of a second intervals. The image coordinates of targets attached to a car were acquired by IDRISI, and the object coordinates were derived based on DLT. This study suggests that home video cameras, a PC, and photogrammetric principles are promising tools for monitoring moving objects and vibrations as well as other time dependent situations.
597 Automatic Extraction of Road Signs from Terrestrial Color
Imagery
Ayman F. Habib, Robert Uebbing, and Kurt Novak
Abstract
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The advent of massive quantities of high spatial resolution
multispectral imagery mandates the development of effective
algorithms to manipulate these data. As a result of this research,
an algorithm for automatic extraction of road signs
from color terrestrial imagery has been developed. The main
premise is to utilize prior knowledge about the color and
shape of these signs to facilitate both hypothesis generation
and verification stages of the recognition process. Any color
can be obtained by combining the three basic colors (red.
green, end blue) with different ratios. Knowing the colors of
the targets of interest, one can define the range of response
in the RGB bands of color imagery to yield this particular
color. This will be the starting point for hypothesis generation
of regions with the predefined colors. Then, the generated
hypotheses must be either verified or rejected, The
verification process will be established through comparing
the geometric properties of the hypothesized regions with
those of the standard targets available in a database, In
other words, the analysis of the multispectral data will initiate
the hypotheses that will later be verified using the geometric
properties of the objects of interest. Interest operators
are used to detect corner points in the hypothesized regions.
These comer points will be matched with those points associated
with the targets of interest using the Generalized Hough
Transform . The ON-SIGHT™ mapping van of TRANSMAP Corporation
has used the suggested algorithm to identify road
signs in captured RGB color imagery. The preliminary results
demonstrate the feasibility and the potential of the suggested
algorithm.
603 Evaluation of NDVI for Monitoring Live Moisture in Three
Vegetation Types of the Western U.S.
Colin C. Hardy and Robert E. Burgan
Abstract
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The Normalized Difference Vegetation Index (NDVI) is evaluated
for monitoring seasonal changes in live vegetation moisture.
NDVI values for scenes of meadow grass, sagebrush, and
an open-conifer stand were calculated using 0.5-m resolution
multispectral images acquired from a fixed-wing aircraft four
times from May to October, and live vegetation moisture was
sampled simultaneously with each flight. Changes in sampled
live vegetation moisture were compared with changes in
the NDVI, and the proportion of seasonal change in NDVI attributable
to changes in the understory vegetation rather
than the conifer canopy was examined. Seasonal changes in
vegetation moisture for all sites were statistically significant
(p<0.05). Time-series profiles of the NDVI were functionally
related to changes in vegetation moisture only for the grass
and forest understory vegetation. No significant relationships
were observed for either the shrub or coniferous forest canopy
vegetation. This field experiment will improve our interpretation
of seasonal NDVI data with respect to fire potential.
611 Remote Sensing of Urban/Suburban Infrastructure and Socio-Economic
Attributes
John R. Jensen and Dave C. Cowen
Abstract
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Temporal and spatial resolution requirements for extracting
urban/suburban infrastructure and socio-economic attributes
from remote sensor data are presented. The goal is to relate
the user information requirements with the current and proposed
remote sensing systems to determine if there are substantive
gaps in capability. Several remote sensing systems
currently provide some of the desired urban/suburban infrastructure
and socio-economic information when the required
spatial resolution is poorer than 4 by 4 m and the temporal
resolution is between 1 and 55 days (e.g., Landsat MSS and
Thematic Mapper, SPOT1-4, Russian TK-350, RADARSAT, Indian
IRS-1 CD, NOAA AVHRR, GOES, Meteosat). Current high
spatial resolution sensor systems such as the Russian SPIN-2
KVR-1000 (2- by 2-m panchromatic; when in orbit) and proposed
sensor systems (EOSAT Space Imaging IKONOS 1 - by
1-m panchromatic; Earthwatch Quickbird 0.82 by 0.82 m;
OrbView-31 by 1 m) may provide additional capability.
Large-scale metric aerial photography or digital camera
imagery with spatial resolutions managing from ≤ 0.25 to 1 m
will still be required to satisfy several important urban/suburban
information requirements.
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