Transcript Spatial databases

Spatial Databases
DT249/DT211/DT228 Semester 2
2006-7
Pat Browne
http://www.comp.dit.ie/pbrowne/Spatial%20Databases%20SDEV4005/Spatial%20Databases%20SDEV4005.htm
Course Web Page
http://www.comp.dit.ie/pbrowne/Spatial%20Databases%20SDEV4005/Spatial%2
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.
HTML Viewer
Java Viewer
(Internet)
GIS Desktop
Applications
Wireless
Mobile
Devices
Network
Custom
Applications
Map Renderer
Spatial
DB
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
where
touches(c1.the_geom,c2.the_geom)
and
c2.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
WHERE
n.class='N7'
AND
n.the_geom && r.the_geom
AND
intersects(n.the_geom,r.the_geom)
AND
c.name='Dublin Belgard'
AND
contains(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 objectoriented 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
http://www.spatial.cs.umn.edu/Book/