Geo-Topics GeoVoCampDC2011 1

Overview of Geo Topics, Vocabularies, Semantics, Examples

Gary Berg-CrossGeoVoCampDC2011

Geo-Topics GeoVoCampDC2011 2

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

Geo-Topics GeoVoCampDC2011 3

Spectrum of Geospatial Information Geometry (Precise), Features, Maps, GeoScience Models

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”

Space

Real WorldObjects

Boundary Boxes For Natural Regions

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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.),

Geo-Topics GeoVoCampDC2011 5

Lots of Taxonomic Vocabularies out there - e.g. COASTAL FEATURES AND SHORELINES 

• 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

• 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 etc.

Geo-Topics GeoVoCampDC2011 6

Darwin Core – from dcterms:Location• 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 • georeferenceRemarksSee

http://code.google.com/p/darwincore/wiki/Location

Geo-Topics GeoVoCampDC2011 7

Class Sketches

• 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

GeographicEntity

Agent-Based Models of Land-Use& Land-Cover Change Report & Review of an InternWorkshop October 4–7, 2001,

dcterms:Location + A spatial region or named place.

Geo-Topics GeoVoCampDC2011 8

3 Parts of Useful Information Semantics

• 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

• Topology of connection/disconnectedness, nearness/farness, & complex regions 2 & 3D structures

• 2-4D Directions, orientations and multiple frames of reference, – 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.

Geo-Topics GeoVoCampDC2011 9

The OpenGIS Feature Geometry (ISO 19107 Spatial Schema) Objects

• GM Object GM Clothoid TP Object• GM Boundary GM Offset Curve TP Boundary• GM ComplexBoundary GM Knot TP ComplexBoundary• GM PrimitiveBoundary GM KnotType TP PrimitiveBoundary• GM CurveBoundary GM SplineCurve TP EdgeBoundary• GM Ring GM PolynomialSpline TP FaceBoundary• GM SurfaceBoundary GM CubicSpline TP SolidBoundary• GM Shell GM SplineCurveForm TP Ring• GM SolidBoundary GM BSplineCurve TP Shell• GM Primitive GM Bezier 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