Spatial Databases Semester 2 DT249/DT211/DT228 Semester Pat Browne

Course Web Page 0Databases%20SDEV4005.htm

Your Interest in Spatial Databases Jobs in GIS  Government  Most major departments are developing GIS on an ongoing basis: e.g. the Geological Survey of Ireland (GSI), Environment Protection Agency (EPA), Duchas, OPW.  Semi-states  Many agencies have a big investment in GIS e.g. ESB.  Local Authorities  County councils run many GIS applications.  Private Sector  MAPFLOW, IMGS (Information with location).  Post graduate research:  DIT Digital Media Centre (DMC), The National Centre for Geocomputation (Maynooth).  Several DT249 students have found new career opportunities as a direct result of completing a spatial database project.

Your Interest in Spatial Databases Technically Interesting  Spatial databases provided the essential logic and structure for a host interesting and creative applications (e.g. emergency services routing, hospital placement, a game environment).  The spatial database course brings together many topics that you have already studied (e.g. databases, graphics, objection orientation, web development) and applies them in innovative ways.  Spatial databases can answer a range of questions from “where is the nearest chipper?” to “is Sellafield killing us?”.  Spatial database work with many other technologies (e.g. Internet,wireless networks, and GPS.) Great source of ideas for final year project.

What is a Spatial Database?  A spatial database is a database system that is optimized to store, update and query spatial objects:  Point: a house, a moving car  Line: a road segment  Polygon: a county

Why Spatial Databases?  Queries to databases are posed in high level declarative manner (usually using SQL)  SQL is the “lingua-franca” in the commercial database world  Standard SQL operates on relatively simple data types  Spatial SQL (SQL3/OGIS) supports several spatial data types and operations  Additional spatial data types and operations can be defined in spatial database. (CREATE TYPE statement)  A DBMS is a way of storing information in a manner that  enforces consistency,  facilitates access,  Allows users to relate data from multiple tables together

Spatial Databases must integrate with other applications and data. Map Renderer Network Wireless Mobile Devices HTML Viewer Java Viewer GIS Desktop Applications Custom Applications Spatial DB (Internet) Server Side Applications

Query 1  “Display all counties that border Kildare”.  This query can be implemented using the following SQL command: select c1.name as name,transform(c1.the_geom,4326) as the_geom from county c1,county c2 wheretouches(c1.the_geom,c2.the_geom)andc2.name='Kildare';

Result 1

Query 2  “Display all regional roads that intersect the N7 National Primary Road within the region of Dublin Belgard” This query can be implemented using the following SQL command: SELECT r.class as name,transform(r.the_geom,4326) AS the_geom FROM regional_road r,national_primary_road n,county c WHEREn.class='N7'AND n.the_geom && r.the_geom ANDintersects(n.the_geom,r.the_geom)AND c.name='Dublin Belgard' ANDcontains(c.the_geom,intersection(r.the_geom,n.the_geom));

Result 2

Course Overview   This course focuses on the use of database management systems (DBMS) to store spatial information. A spatially enabled DBMS is a central component of a Geographical Information System (GIS). GIS has a major role to play in managing the national physical and informational infrastructure. An understanding of spatially enabled DBMS is vital in implementing any information system where geographic data is required. This course focuses on the role of the DBMS in geographical applications.

Course Description 1   Foundations Fundamental geographic concepts for GIS The world in spatial terms, how natural and man made features can be stored in a DBMS. Qualitative and quantitative location e.g. geo-referencing and coordinate systems. Maps as representation of the world and of information. Geometric and thematic information.

Course Description 2   Algorithms for GIS: Intersection of lines, operations on polygons, network traversal, auto-correlation, statistical operations, searching. We focus on the use of algorithms, not their design. The algorithms are provided as database extensions (e.g. PostGIS) or Java APIs (e.g. Open Map, Geotools, uDig, JUMP)

Course Description 3   Spatial representations: Raster, vector, TIN, quadtrees, R-trees, scan orders, polygon coverage, discrete objects, networks, time, connections and topology, networks, distance and direction, flow and diffusion, spatial hierarchies, boundaries, spatial patterns, attributes of relationships. As with the algorithms these representations are provided by the DBMS and APIs.

Course Description 4   Applications of geospatial data: Transportation networks, natural resources, soil data, oceanography, land cover, geology, climate, terrain modelling, land records, administrative boundary data, demographic studies, decision support and health data.

Course Description 5   Spatial databases Spatial data: definitions, formats, models, queries the relational model, advanced SQL, data modelling techniques, implementing a simple database, post relational database models, object-relational and object- oriented models, spatial data structures, spatial indexing e.g. R-Tree, networking, database issues in GIS. The course will involve practical work on a range of appropriate software e.g. PostgreSQL, PostGIS, GML, Java, ArgoCaseGEO, OPENMAP, uDIG.

Learning Outcomes   On completion of the spatial database module, you will be able to:   use a database to store and query spatial data   develop applications that use a spatially enabled DBMS   understand and use the OGC simple feature model   distinguish and use appropriate database models   understand the DBMS extensions and APIs required by application programs to handle spatial data.

Course Text The course text is: Spatial Databases: With Application to GIS by Philippe Rigaux, Michel Scholl, and Agnès Voisard Publisher Elsevier Google Books

Good Reference Spatial Database Book Project