Heterogeneous Geographic Objects Interoperability

Victor Azevedo

vhmeirelles@gmail.comMaster Student in Geomatics/UERJ

Geoinfo, 2006

Margareth Meirelles

Rodrigo Ferraz

Antônio Ramalho Filho

Summary

• Motivation and Goals

• Some Concepts

• Methodology

• Case Study

• Results

• Conclusions and Future Works

Motivation

Biofuel government program;

Agro-Ecological Palm Oil Zoning in Legal Amazon deforested areas (MCT - Embrapa);

Exchange soil geographic data among heterogeneous geographic data sources (SIPAM, IBGE, EMBRAPA and others)

Possible Contributions

Inherits geographic data from different institutions;

Data acquisition represents 60% - 80% of GIS implementation cost [Hartman 1998];

Geographic Data Consortium;

Use distributed environment (internet) to exchange geographic data.

= Exchange information among different geographic data producers;

Goals

Propose a methodology to provide the interoperability among heterogeneous and distributed geographic objects (features) considering the syntactical, semantic and data format integration aspects;

Contribute to the development of researches in spatial data integration

Specific Goals

Propose an automatic integration of distributed heterogeneous geographic objects, based on:

Open Geospatial Consortium (OGC) Specifications of Geographic Markup Language (GML) and Web Feature Services (WFS) plus domain ontology in Ontology Web Language (OWL) and metadata structure

Specific Goals

Model the expert soil knowledge based on ontology sharing the results in OWL format.

Develop a prototype to integrate two soil geographic data sources providing the result in a known geographic format;

Apply the methodology to the project: Agro-Ecological Palm Oil Zoning in deforested areas of Legal Amazon (data from Embrapa Solos, IBGE, SIPAM and others institutes).

Summary

• Motivation and Goals

• Some Concepts

• Methodology

• Case Study

• Results

• Conclusions and Future Works

GIS Interoperability

Heterogeneous Formats

Shapefile

GML

DGN

PostGIS

TIFF GeoTIFF

DXFMIF

Oracle Spatial

DLG

MySQL

MrSID

ArcSDE

GIS Interoperability

GIS 1

FORMAT X

GIS 2 FORMAT Y

Spatial Data Model

GIS 3

FORMAT Z

??

How to make GIS Interoperability?

Solving incompatibilities in three levels [Casanova et al 2005]:

Formats

Syntax

SemanticsStandardization

Summary

• Motivation and Goals

• Conceptualization

• Methodology

• Case Study

• Results

• Conclusions and Future Works

Methodology

Geographic Object Servers (GOS) definition;– Provide Geographic Data in GML using a WFS Server.

Integration Server(s) (GeoIS) definition;– Register each GOS;– Register Domains and Ontologies;– Correlates domain terms with GOS terms;– Generate the integrated version of Feature Collection.

Service Oriented Architecture

(SOA) Definition

Methodology

For each geographic data source, publish the geographic objects in GML using a WFS Server;

Some GIS and Map Servers implement the OGC WFS specification;– Geoserver, MapServer, MapGuide, ArcIMS, etc…

Service Oriented Architecture

(SOA) Definition

Provide Geographic

Objects in GML with WFS

OGC WFS-T

Client Server

Request (GetCapabilities)

XML Document (WFS Capabilities)

Request (DescribeFeatureType)

XMLSchema Document (WFS Schema)

Request (GetFeature)

GML Document (WFS FeatureCollection)

Request (Transaction)

Document (WFS Transaction Response)

Geographic Object Repository(PostGis, Oracle Spatial,

Shapefile, etc.)

Geographic Object Server (GOS)

Internet / Intranet

WFS

Client

Service Request

GML Response

ConversorConverts the Geographic Objects to GML Features

WFS Server Engine

Distributed Environment

Geographic Object Repository(Postgis, Oracle Spatial, Shapefile, etc.

Methodology

Generate the ontology for each integration domain– Terms and Relationship in a formal way

The domain ontology is the referential conceptual schema

Syntactical and semantic reference for the knowledge area– Uniform Syntax and Semantic for integration

Service Oriented Architecture

(SOA) Definition

Provide Geographic

Objects in GML with WFS

Knowledge Engineering

Process

Methodology

Register each domain– Ontologies in OWL

Register each GOS in the Integration Server (GeoIS)– Location (URL) , Feature Type and Metadata

Make the syntactical and semantic correlation among each GOS Schema and the OWL Ontology– WFS DescribeFeatureType <-> OWL Terms

Service Oriented Architecture

(SOA) Definition

Provide Geographic

Objects in GML with WFS

Knowledge Engineering

Process

Integration Server

Implementation

Methodology

Generate and Publish unified Feature Collection with the geographic objects from each data source registered in GeoIS;

Preferred formats – GML through WFS Map presentation in WMS.

Service Oriented Architecture

(SOA) Definition

Provide Geographic

Objects in GML with WFS

Knowledge Engineering

Process

Integration Server

Implementation

Integrated Geographic

Objects Publication

Methodology Activity Diagram

?

GIS InteroperabilityNew Scenario

Summary

• Motivation and Goals

• Conceptualization

• Methodology

• Case Study

• Results

• Conclusions and Future Works

Case Study

Agro-Ecological Palm Oil Zoning in deforested areas in Amazon;

Biofuels utilization; Integration of soil geographic data from project

data sources; Embrapa; IBGE (web); SIPAM; Others.

Domain : Soil attributes to land evaluation.

Study Area

IBGE

SIPAM

Data Sources Used

SIPAM Dual Architecture (Oracle + Shapefile) Scale: 1:250.000 All Amazon Region Restrict Information.

IBGE Shapefile + dbf Scale: 1:250.000 Amazon Boundary region Public Information (http://www.ibge.gov.br).

Heterogeneous!!!!

Materials

PostGIS SIPAM Geographic Data Source - conversion from dual

architecture (Shapefile + Oracle) to spatial database PostGIS; ArcGIS

IBGE Geographic Data Source (shapefile) - unification of geometry and necessary attributes;

GeoServer Configuration of WFS Services;

Protégé OWL Creation of Knowledge Base in OWL

Java J2EE Server Integration Application Geotools 2.1 – WFS Functions utilization and result generation Protégé OWL API – Get Ontology terms to correlation

Methodology Application

Service Oriented Architecture

(SOA) Definition

SIPAM GeographicData Source

(Soils)

SIGEO

SOG-SIPAMSOG-IBGE

Embrapa Intranet

cartas_fronteira_ibge.shp

IBGEData Source

(Soils)

IBGE Data Source

(Soils)

SIPAM Data Source

(Soils) cartas_fronteira.shp

Methodology Application

Service Oriented Architecture

(SOA) Definition

Provide Geographic

Objects in GML with WFS

Query Server Capabilities

Server Name

Feature Type Name

Query Server Schema (XMLSchema)

GML MultiPolygon Type

All Schema in XMLSchema

Methodology Application

The Knowledge Engineering Process Interactive Process - GIS Experts and the researches

from Embrapa Soil Research Center Generation of 3 Knowledge Bases (Ontologies): i) soil

attributes for land evaluation; ii) land evaluation in general; iii) land evaluation specific for palm oil;

Ontology Editor: Protégé OWL

Service Oriented Architecture

(SOA) Definition

Provide Geographic

Objects in GML with WFS

Knowledge Engineering

Process

«file»AtributosSoloAptidao.OWL

«file»SIBCS.OWL

«file»Aptidao_Agricola.OWL

«file»Aptidão_Agricola_Dende.OWL

«import»

«import»

«import»

«file»OGC-GML.OWL

«import»

Methodology Application

Knowledge Base

Map Unit is-a FeatureType

Ontology and GML Integration

Map Unit Properties

Methodology Application Land evaluation soil attributes (AtributosSoloAptidao.owl)

Methodology Application

Java Implementation Important Open Source Java Libraries used:

Protégé OWL API Geotools 2.1.1

Service Oriented Architecture

(SOA) Definition

Provide Geographic

Objects in GML with WFS

Knowledge Engineering

Process

Integration Server

Implementation

Domains

Ontology file (OWL)

Geographic Data Sources

Domain Relationship

Metadata

Service Location

FeatureType Name

Correlation Table

GOS Property Schema

Ontology Terms (Reference Schema)

Methodology Application

New Map Registration Creation of integrated map All the geographic objects (features) from

different data sources with the same schema Output Format: Shapefile (for this case study)

Service Oriented Architecture

(SOA) Definition

Provide Geographic

Objects in GML with WFS

Knowledge Engineering

Process

Integration Server

Implementation

Integrated Geographic

Objects Publication

New integration map

Geographic Data Sources that must be integrated

Download integrated map files

Summary

• Motivation and Goals

• Conceptualization

• Methodology

• Case Study

• Preliminary Result

• Conclusions and Future Works

Same Map

Two Different Geographic Data Sources

Selected map unit data source (IBGE)

Reference Schema

Ontology

Another Map Unit Selection

Selected map unit data source (SIPAM)

Same Reference Schema

Summary

• Motivation and Goals

• Conceptualization

• Methodology

• Case Study

• Results

• Conclusions and Future Works

Conclusions

Semantic, format and syntax standardization can be a way to interoperability;

The proposed methodology showed good results as a solution to the integration of heterogeneous geographical data sources (when applied to Amazon soil data sources);

The use of WFS tools presented potential to unify different formats in GML.

Protégé OWL framework succeed in representing experts knowledge;

Difficult to work with Geotools and Protégé OWL API – sometimes it is necessary to change the source code.

Future Works Include in the methodology Web Register Service and OGC

Catalog Service standards to register the Geographic Objects Servers Services (GOS) and the metadata respectively;

Ontology-based querying to distributed geographic objects;

Provide different output formats: GML and OWL individuals;

Apply the work for all Legal Amazon Region;

Make inferences about generated OWL file (automated land evaluation generation).

QuestionsQuestions

??Victor H. M. de Azevedo

vhmeirelles@gmail.com

Thanks for the attention!Thanks for the attention!

Query Feature Collection

Geodetic Reference System – Use the EPSG (www.epsg.org) Geodetic Parameter Dataset.

GEOGCS["SAD69", DATUM["South_American_Datum_1969", SPHEROID["GRS 1967", 6378160.0, 298.247167427, AUTHORITY["EPSG","7036"]], AUTHORITY["EPSG","6291"]], PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]], UNIT["degree", 0.017453292519943295], AXIS["Lon", EAST], AXIS["Lat", NORTH], AUTHORITY["EPSG","4291"]]

Feature Data