Open Source Databases and GIS Flexible Technologies for Flexible People

Open Source Databases What Open Source Databases are there? MySQL PostgreSQL Berkeley DB mSQL SAP DB InterBase

Berkeley DB Embedded database Widely used in software Extremely fast Sendmail Netscape Extremely fast Only usable via language bindings C, C++, TCL, Python Commercially Supported Sleepycat Software

MySQL Most widely used OSDB Very fast read access, good for web apps SQL interface, ODBC, JDBC Language bindings C, C++, Perl, Python, TCL Commercially supported MySQL AB NuSphere

PostgreSQL Most extensible OSDB Object relational design ACID database SQL interface, ODBC, JDBC Language bindings C, C++, Perl, Python, TCL Commercially supported PgSQL Inc Red Hat (as Red Hat Database)

Why Not Oracle? Complexity Overhead Cost Accessibility OSDBs are relatively simple to install and administer Overhead OSDBs have a lighter system footprint Cost OSDBs have no licensing fees Accessibility OSDBs are not a black box

When to use an OSDB? When it is organizationally appropriate When you are accessing data using standard APIs When you are building web based applications When you are building deployable applications When you control the architecture from end to end

Spatial Data and RDBMs Spatial Databases Spatial data and attributes reside together in the database Complex hybrid queries are possible select area(forestpoly) from forestcover,history where forestcover.ageclass > 80 and history.restocking = true and forestcover.fid = history.fid and distance( forestcover.forestpoly, GeometryFromText(’POINT(514234,5019313)’,26910) ) < 500 Very large seamless datasets can be stored Unified data models are possible

Spatial Databases Proprietary software Open source software ArcSDE DB2 Spatial OracleSpatial Open source software PostGIS / PostgreSQL

PostGIS / PostgreSQL Spatial database functionality in PostgreSQL OpenGIS “Simple Features for SQL” (SFSQL) as design guide

PostGIS Objects OpenGIS SFSQL Objects OpenGIS SFSQL Representations POINT, LINESTRING, POLYGON, MULTIPOINT, MULTILINESTRING, MULTIPOLYGON, GEOMETRYCOLLECTION OpenGIS SFSQL Representations AsBinary()  Well-Known Binary AsText()  Well-Known Text POINT(-128 45) MULTILINESTRING((-128 45,-128 46),(-130 50,-131 55))

PostGIS Functionality Spatial indexing for all object types R-Tree on GiST Index Analysis functions Area() Length() Distance() Transform()

PostGIS Data Access Loading / Dumping Java C/C++ Includes shp2pgsql and pgsql2shp utilities OGR utility allows importing from multiple formats E00Pg utility allows importing from E00 files Java Includes JDBC Extension Objects for Geometries C/C++ Using Well-Known Binary over the PostgreSQL C/C++ API

PostGIS Data Visualization Internet mapping with Mapserver PHP/Mapscript and PHP/PgSQL to build interactive web mapping applications ArcIMS emulator with Mapserver to view PostGIS data within Arc8 Java mapping with GeoTools GeoTools has a beta PostGIS layer data source

PostGIS in the Real World (1) Queensland, Australia Department of Natural Resources Forestry permitting internal web application Query database by attribute and return map of parcel area with supporting information from database City of Boston, USA Online property analysis internal web application Identify parcels which are proximate and display results using Mapserver

PostGIS in the Real World (2) I-Cubed Inc, USA Large automated image processing system Uses database to coordinate image processing functions, tracking spatial extents of incoming requests and required imagery and farming work out to client computers. Intevation Gmbh, Germany Massive multiplayer online game Players will have mobile devices (pagers, cell phones) and their position recorded in the database. Extraction and visualization tools will be used to visualize game play.

PostGIS in the Real World (3) Finnish Geodetic Institute Creating nationwide distributed GIS network using the GeoServer OpenGIS WFS with PostGIS as the database backend Refractions Research, Canada Maintaining the Digital Road Atlas, a richly attributed provincial road network. Geometries are integrated into a complex data model including versioning, network integrity, and multiple views of the data.

In Conclusion Open source databases have the capabilities to handle real world problems, and are in widespread use Open source spatial databases (PostGIS) are new, but are already in use around the world Many GIS database problems can now realistically be addressed with open source technology