Schema transformations: From Production Database to INSPIRE data using WFS Experiences from ELF Nordic cluster

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1 Schema transformations: From Production Database to INSPIRE data using WFS Experiences from ELF Nordic cluster Presentation to: Author: Date: INSPIRE Schema transformation workshop Mauritz Bomark, Frank Arntsen, Kent Jonsrud, Jarle Pedersen, Roy H. Mellum June 16 th June, 2014

2 ELF Nordic cluster Established as a task force in ELF Finland, Sweden and Norway Develop/prototype National download services(inspire conform WFS 2.0) with GML encoding. Implement ELF(NMCA profile of Inspire) Draft Data Specifications for Master level data(high resolution). Eleven 11 selected Inspire Themes. Work started(3th of Dec.2013) almost from scratch Same approach and many common tools chosen in all 3 countries

3 Our focus and basic principles Delivery point close to the source data. As few steps as possible from the source database to the Inspire valid GML output. Actual and authoritative information directly from the official source. Deliver full INSPIRE valid GML. Use open source software if possible.

4 Architecture potential methods Client applications that use INSPIRE WFS/GML Web Feature Service (INSPIRE Download Service) Schema transformation Database views Distribution database Database tools Transformationsoftware Other methods Production database or replicated production database

5 Transformation in two levels 1. Application Schema Level (Model level) National specifications (Data models) Documentation of the transformation INSPIRE Data specification Resources: Domain experts and data modelling experts 2. Data level National database Technical implementation of the transformation INSPIRE valid GML via WFS Resources: Database experts and service developers The result of level 1 is used as input for level 2

6 Model mapping using Mapping Tables Example AU theme IGN F Left hand side ELF/INSPIRE model Right Hand side NMCA Model

7 Model mapping using Mapping Tables

8 Model mapping using Mapping Tables

9 Transformation using Database views In this method the most ogfthe transformation is taking place on the database level and implemented as database views. The database views are designed to fit the Inspire data model. Standard SQL is used to select information from different tables, change content values and structure. Transformation is processed "live" for each request. The transformation is done efficiently close to the original data. Can handle complicated transformations.

10 Example : Norwegian Cadastral Parcels Production database Internal model INSPIRE model Database tables Database views or materialized views matrikkel nummer matrikkel nummer gyldig fra område areal slutt dato national Cadastral Reference valid From valid To geome try area Value

11 Architecture Norwegian Cadastral Parcels Production system Delivery system Access control Norwegian Central cadastral system server (View Service) Database views INSPIRE model Download service INSPIRE data specification Central Cadastral Information database Oracle Replicated Cadastral database Oracle

12 Transformation using Database tools Data is transformed with SQL scripts and database functions. The transformed content is loaded into a separate distribution database structured according the Inspire model. The transformation is performed as scheduled process. Can handle complicated transformations. The transformation is done efficiently using database tools. The transformation work can be handled separate from the production system. Can give better performance than database views since the database can be more specialized for delivery.

13 Software Tools deegree WFS server Support INPIRE requirements WFS version og GML version Model driven approach PostgreSQL database med PostGIS In some cases Oracle database

14 Mapping in deegree SQL feature store: Support PostGIS, Oracle and MS SQL data bases. Support flexible mapping of GML application schemas to relational models.

15 Selecting Mapping setting Relational: Configure highly flexible mappings between feature types and database tables.

16 ELF WP 3 National Services so far *developed since Dec 2013 Inspire theme No of National WFS Administative Units(AU) 6 Adresses(AD) 3 Buildings(BU) Cadastral Parcels(CP) 3 Geographical Names(GN) 6 Hydrography(HY) 3 Transport network(tn) 1 Protected sites(ps) Sea Regions (SR) Elevation(EL) Landcover(LC)