hydrologic ontologies framework michael piasecki department of civil, architectural, and...

Hydrologic OntologiesFramework

Michael PiaseckiDepartment of Civil, Architectural, and Environmental Engineering

Drexel University

SICOP-Forum Expedition Meeting Arlington, VA

June 28, 2005

Drexel University, College of Engineering


Why Hydrologic Ontologies?

1. To resolve semantic heterogeneities between disparate metadatadescriptions, e.g. “Gauge Height = Stage = Stream Gauge”, by representing metadata profiles in the Web Ontology Language.

2. To create a Hydrologic Controlled Vocabulary for navigation and discovery of hydrologic data, e.g. a framework that aids discovery(on a more generalized level) and defines markup (on a finer or “leaf” level) to identify specific data sets within a Digital Library.

3. To develop a conceptual representation for the Hydrologic Domainwithin which data discovery and information extraction can be inferredfrom knowledge representations.

Lets focus on this ……………


Domain and Scope of Hydrologic Ontologies

Basic questions:• What is the domain that the ontology will cover?• For what we are going to use the ontology?• For what types of questions the information in the ontology should provide answers?• Who will use and maintain the ontology?

Competency questions (litmus test): • What streams belong to Hydrologic Unit XYX?

• What is the net volume flux in watershed A for month Y?• What was the accumulated rainfall in region Y because of storm X?• What is the discharge time-history at point X as a result of storm Y passing through?• ???

ISO 19103 Units/Conversion


Ontology Examples

Status

We currently have

ISO 19108 Temporal Objects

USGS Hydrologic Unit CodeISO 19115 Geospatial

Hydrologic ProcessesSedimentation

ARCHydro

What we need is

Many More

Many More

Many More

Many More

Upper Hydrologic Ontology

http://thor.cae.drexel.edu/~bora/temporal.html


Example Use


GEON sponsored Workshop

• San Diego Supercomputer Center January 27-28, 2005Many thanks to Chaitan Baru (agree to sponsor) and Margaret Banton for organizing.

• ParticipantsMichael Piasecki Drexel University (convener)David Maidment University of Texas, AustinThanos Papanicolaou University of IowaEdwin Welles NOAA, National Weather Service, OHDLuis Bermudez Monterrey Bay Aquarium Research Institute (MBARI)llya Zaslavsky SDSCKai Lin SDSCAshraf Memon SDSC

• Objective:Discuss concepts for Upper Hydrologic Ontology


A few rules:

1) There is no one correct way to model a domain— there are alwaysviable alternatives. The best solution almost always depends on theapplication that you have in mind and the extensions that you anticipate.

2) Ontology development is necessarily an iterative process.

3) Concepts in the ontology should be close to objects (physical or logical)and relationships in your domain of interest. These are most likely to benouns (objects) or verbs (relationships) in sentences that describe yourdomain.

Be cognizant of ……….


1st Alternative Hydrologic Ontologies

GeoVolume concept horizontal slices no vertical tracing

class:hydrology

subclass:precip

subclass:………

subclass:……..

subclass:atmos water

subclass:surface water

subclass:sub-surf. water

15 km

~2 m

-1 km

Pros: categorization along spatial separations, easy to followclosely linked to hierarchical structure of CVtraditional linkage to disciplines and sub-disciplines horizontal flow path is well representedmodel domains are typically aligned with horizontal layers

Cons:vertical flow (budget) not represented wellneed prior knowledge in which domain to search for dataprocesses are sub-items on low levels of ontology, this may not suit the general idea of moving from more general to more specific concepts


2st Alternative Hydrologic Ontologies

Measurement concept everything is a measure expand to include phenomena & features

Feature:Basin

Curve-#

……


3st Alternative Hydrologic Ontologies “Interests” concept models (prediction, analysis) data models (obs, measurements) processes (phenomena) representations (maps, time series, …)

Feature

Waterbody

HydroIDHydroCodeFTypeNameAreaSqKmJunctionID

HydroPoint

HydroIDHydroCodeFTypeNameJunctionID

WatershedHydroIDHydroCodeDrainIDAreaSqKmJunctionIDNextDownID

ComplexEdgeFeature

EdgeType

Flowline

Shoreline

HydroEdge

HydroIDHydroCodeReachCodeNameLengthKmLengthDownFlowDirFTypeEdgeTypeEnabled

SimpleJunctionFeature

1HydroJunction

HydroIDHydroCodeNextDownIDLengthDownDrainAreaFTypeEnabledAncillaryRole

*

1

*

HydroNetwork

*

HydroJunction


HydroJunction


Data Model ArcHydro

class:hydrology

subclass:Sediment

subclass:Heat Flux

subclass:Flooding

subclass:models

subclass:data

subclass:processes

dimension

Type

….

Pros: direct link to processes & data models of interestcan link data sets directly with processescan make use of many already existing conceptualizations models (statistical, deterministic etc) can be well mapped

Cons:not very good for hierarchical navigationthere is no general -> specific transitiondifficult when trying to use for CV or keyword lists might be difficult for “new” knowledge discovery


Outcomes Hydrologic Ontologies

• Development of a higher level Hydrologic ontology based on the afore mentioned concepts. The group felt no clear affinity for one or the other concepts. As a result, two top ontologies may need to be developed and placed next to each other. Depending on the taskat hand a user may use either one of them to address the objective.

• Development of lower ontologies that can be merged with the top ontology. a) development of ontologies from database schema (like ARCHydro and the NWIS data base) via XML schema libraries b) development of a processes (or phenomena) ontology c) development of modeling ontology d) inclusion of very task specific (service) ontologies, e.g. units, temporal

• Development of a well defined Hydrologic Controlled Vocabulary that can be used to query the hydrologic realm. One suggestion made was to use common queries as a starting point to identify important aspects in the taxonomy of the CV.


HYDROOGLE

Application Hydrologic Ontologies

Upper Ontology:Measurements

Lower Ontology:HUC system

coupled with

http://loki.cae.drexel.edu:8080/web/how/hydroogle/


Thank you

Questions?

http://loki.cae.drexel.edu:8080/web/how/me/metadatacuahsi.html

hydrologic ontologies framework michael piasecki department of civil, architectural, and...

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