Problem with GIS Data

1
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
• ?

2
Data Complexity

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

3
Sharing Tools

• Wont 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

4
Geodatabases

• Definition for a complex set of data
• Stored in a Geodatabase
• Easily shared

Data Model in a Can
5
ESRI Approach

• Create their own database structure within a
  database
• Add users 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

6
Arc Data Storage
Shapefiles Coverages GeoDatabases
Collection of datasets Folder of Shapefiles ArcInfo Workspace GeoDatabase
Dataset Folder of Shapefiles Coverage Feature dataset
Collection of features Shapefile Feature class Feature class
Features Point, Multipoint, Polygon, Polyline Point, Polygon, Polyline, etc. Point, Multipoint, Polygon, Polyline, Network Annotation
7
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

8
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

9
New File Geodatabase
10
The Can
11
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

12
New Feature Dataset
13
GDB with Feature Dataset
14
Feature Class

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

15
New Feature Class
16
Feature Class vs. Shapefile
17
File Geodatabase Structure

• Disk
• Folders
• Geodatabase.mdb
• FeatureSet
• FeatureClass
• Relationships
• Tables
• Etc.

18
Data Color-coding
19
References

• Arctur, D. and Zeiler, M., 2004, Designing
  Geodatabases, ESRI Press
• Lowe, J.W., 2003. Flexible data models strut the
  runway. Geospatial Solutions, 13(2) 44-47.
• Maidment, D.R., 2002. Arc Hydro GIS for Water
  Resources, ESRI Press, 203 pp. w/CD.
• Li, X. and M.E. Hodgson, 2004. Vector-field data
  model and operations. GISci. Rem. Sens., 41(1)
  1-24.
• Wright, D., Blongewicz, M., Halpin, P., and
  Breman, J., Arc Marine GIS for a Blue Planet,
  Redlands ESRI Press, 2007.
• In Digital Earth or dusk.geo.orst.edu/djl/arcgis/b
  ook.html