Transcript Intro to Geo-Topics

Overview of Geo Topics, Vocabularies,
Semantics, Examples
Gary Berg-Cross
GeoVoCampDC2011
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Why Discuss Geographic & Geo-Science Semantics?
Movement towards a “seamless integration of
geospatial intelligence (and Geospatial or
Geo-Science applications) into mainstream IT
solutions.”
– Geo-Info needs support from better, useful
information semantics
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Spectrum of Geospatial Information
Geometry (Precise), Features, Maps, GeoScience Models
Boundary Boxes
For Natural Regions
Real World
Objects
Space
A polygonal area. <meta name="DC.coverage.spatial.region"
content="1 1, 4 2, 5 4, 3 6, 2 3, 1 1"> Some precise math
used for the geometry/shape of “features”
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Geographic and Geo-Science Semantics
• Geo-Science builds on Geo-Spatial semantics and adds some
new vocabulary
• Examples include:
– Geographic Entities have Regions…Land Use (Forests, Grass..),
Land Cover (Tree, Shrub..) & Dynamics
• Land cover, biophysical attributes of the Earth’s surface, is a
geographical feature class using climate, geology, soil type and
landform features
– these form a reference base for important applications ranging from
forest & rangeland monitoring, planning, investment, biodiversity,
climate change, desertification control, residential living, farming,
production of business statistics etc.),
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Lots of Taxonomic Vocabularies out there - e.g.
COASTAL FEATURES AND SHORELINES
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Abandoned shoreline
Ancient beach ridges
Ancient cuspate bar,
split and tombolo
Barrier beach
Battered sea cliff
Bay
Bay, Carolina
Bayhead bar
Baymouth bar
Bayou
Beach
Bonneville and Provo shoreline
Cape
Coastal Bars
Coastal terrace
CoveCrowsfoot delta
Deltaic channels
Distributary channels,
Abandoned Distributary channels
Distributary stream on delta
Diverted outlet
Drowned coast line
Drowned river
Drowned valley
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Estuary
Fiord
Headland,
truncated
Lagoon
Marine terrace
Neck
Okefenokee terrace
Pamlico shoreline
Pamlico terrace
Pass
Point
Prograded shore
Raised beach ridges
Raised spit and hook
Sand spit
Sea stacks
Silver Bluff beach, lagoon, and shoreline
Silver Bluff terrace
Spit, compound recurved
Tidal marsh or swamp
Tombolo
Wave-cut cliff
Wicomico terrace
ESCARPMENT FEATURES , GLACIATION
FEATURES FORMED BY ALPINE GLACIATION
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Darwin Core – from dcterms:Location
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locationID
higherGeographyID
higherGeography
continent
waterBody
islandGroup
island
country
countryCode
stateProvince
county
municipality
locality
verbatimLocality
verbatimElevation
minimumElevationInMeters
maximumElevationInMeters
verbatimDepth
minimumDepthInMeters
maximumDepthInMeters
minimumDistanceAboveSurfaceInMeters
maximumDistanceAboveSurfaceInMeters
locationAccordingTo
locationRemarks
verbatimCoordinates
verbatimLatitude
verbatimLongitude
verbatimCoordinateSystem
verbatimSRS
decimalLatitude
decimalLongitude
geodeticDatum
coordinateUncertaintyInMeters
coordinatePrecision
pointRadiusSpatialFit
footprintWKT
footprintSRS
footprintSpatialFit
georeferencedBy
georeferenceProtocol georeferenceSources
georeferenceVerificationStatus
georeferenceRemarks
See
http://code.google.com/p/darwincore/wiki/Locat
ion
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Class Sketches
dcterms:Location + A spatial region or named place.
Geographic
Entity
Agent-Based Models of Land-Use
& Land-Cover Change Report & Review of an Intern
Workshop October 4–7, 2001,
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One might sketch out some scope of interest and ground these is a general
concept and some terms of interest – for example landscapes or landforms
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3 Parts of Useful Information Semantics
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A vocabulary that defines the nature of the instances and their
descriptive attributes. Rivers, streams & brooks.
So a geospatial vocabulary should allow a way of talking about
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Topology of connection/disconnectedness, nearness/farness, &
complex regions 2 & 3D structures
2-4D Directions, orientations and multiple frames of reference,
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Earth’s north-south, our left-right, boat’s port-starboard, upstream…
Shape, size, length, distance, area, volume and scale,
Dimensions
Spatial aggregates etc.
A schema (explicit) of some nature that describes the structural
relationships amongst instances and their characteristics, and
A mapping of the above to existing DB schema or constructs that
help place real data into context.
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The OpenGIS Feature Geometry (ISO 19107 Spatial
Schema) Objects
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GM Object
GM Boundary
GM ComplexBoundary
GM PrimitiveBoundary
GM CurveBoundary
GM Ring
GM SurfaceBoundary
GM Shell
GM SolidBoundary
GM Primitive
GM Clothoid
GM Offset Curve
GM Knot
GM KnotType
GM SplineCurve
GM PolynomialSpline
GM CubicSpline
GM SplineCurveForm
GM BSplineCurve
GM Bezier
TP Object
TP Boundary
TP ComplexBoundary
TP PrimitiveBoundary
TP EdgeBoundary
TP FaceBoundary
TP SolidBoundary
TP Ring
TP Shell
TP Primitive…..
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Example of Types of Improvements to Semantics
• Understanding the Domain
– What’s the general usage of terms in a domain?
• Area feature - A geographic entity that encloses a region; for example, a
landscape, lake, administrative area, or state.
– Geographic entity - A real-world feature that is of interest; something about
which data is stored.
– 65 feature classes listed in USGS Gazetteer Feature Classes
• Describing that understanding in “better” vocabularies
– Both rivers and trees have branches but these terms are not the
same concept.
• Ontologies are more like full logical theories provide a better defined
vocabulary of terms
– These describe domains in terms of general (classes), that are
explicitly related and logically constructed from base terms
• rivers are bodies of water, (sub-type relation)
– as well as provide roles and relationships between instantiated
individuals
• The source of the North Branch Potomac river is in West Virginia
– New terms can be formed by combining existing ones
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