Problem with GIS Data Lots of different, related files Results in data that is: –Hard to find and share and of questionable quality Need: –Containers for datasets: File Geodatabases? –Standards for complex data: Data Models? –Protocols for maintaining quality: ?

Data Complexity Shapefile: –shp: spatial data –dbf: attributes –shx: index –xml: metadata –prj: SRS Would be nice if this was all in one file

Sharing Tools Won’t it be great if we could use tools like model builder to work on the city of Arcata, then use the same tools to work on the city of Eureka, etc. Need a common format for all the spatial data –Roads, rail lines, parks, water mains, parcels, hydrants, zoning areas, etc

Geodatabases Definition for a complex set of data Stored in a Geodatabase Easily shared Data Model in a “Can”

“Databases” Flat-File Database –No relationships –Single-user access –One file –Examples: MS-Access (mdb file) Relational, Enterprise Level Databases –Multi-Access –Runs as a “Service” on a “Server” –Examples: Oracle, MS SQL Server, PostgreSQL, MySQL

Introduction to Databases Tables like Excel Relationships between the tables XYDBHType PP LP LP LP AbrveNameBFCost PPPonderosa Pine.98 LPLodge Pole1.10

ESRI Approach Create their own database structure within a database –Add user’s data into the Esri structure Personal File Geodatabase –MS-Access –Not supported in the future Relational Databases –Supported through Arc Spatial Database Engine (ArcSDE) File Geodatabases

Arc Data Storage ShapefilesCoveragesGeoDatabases Collection of datasets Folder of Shapefiles ArcInfo Workspace GeoDatabase DatasetFolder of Shapefiles CoverageFeature dataset Collection of features ShapefileFeature class FeaturesPoint, Multipoint, Polygon, Polyline Point, Polygon, Polyline, etc. Point, Multipoint, Polygon, Polyline, Network Annotation

Spatial Databases Oracle Spatial –Used for utilities, 3D –Expensive, requires special support staff PostgreSQL w/PostGIS –Free –Fast –Not bad to support SQL Server –Reasonably priced –Fast –Easy to support

File Geodatabase Advantages: –Easy to share complex vector datasets Disadvantages: –Internal structure is hidden –Basically, only supported by Esri products –Raster databases can be huge Note: –Geodatabases used to be the only way to fix topology problems, now they can be fixed with shapefiles as well

File Geodatabase Folder with “.gdb” extension! Additional data types & capabilities: –Relationships –Topology Rules –Feature Dataset –Raster Catalog & Mosaic –Networks The default for data created from the tool box

New File Geodatabase

The “Can”

New Terminology Feature Dataset –Set of vector data (points, polylines, polygons) –Common Spatial Reference Raster Dataset (not recommended) –Set of rasters –Common Spatial Reference Dataset is like a folder Name should include Spatial Reference –WGS84_UTM_10_North

New Feature Dataset

GDB with Feature Dataset

Feature Class Data for one layer of vector data Points, Polyline, or Polygon Has spatial data, attributes, metadata Effectively, a shapefile

New Feature Class

Feature Class vs. Shapefile

File Geodatabase Structure Disk –Folders… Geodatabase.mdb –FeatureSet »FeatureClass »Relationships »Tables »Etc.

Data Color-coding yellow coverage gray geodatabase green shapefile

References Arctur, D. and Zeiler, M., 2004, Designing Geodatabases, ESRI Press Lowe, J.W., Flexible data models strut the runway. Geospatial Solutions, 13(2): Maidment, D.R., Arc Hydro: GIS for Water Resources, ESRI Press, 203 pp. w/CD. Li, X. and M.E. Hodgson, Vector-field data model and operations. GISci. Rem. Sens., 41(1): Wright, D., Blongewicz, M., Halpin, P., and Breman, J., Arc Marine: GIS for a Blue Planet, Redlands: ESRI Press, In Digital Earth or dusk.geo.orst.edu/djl/arcgis/book.html