“Models” Another word that is really over used: –Model builder: Really process flows –Modeling: Creating mathematical and logical models of real-world phenomenon –Data Model: Simple “typed” data –A data set (i.e. a shapefile, a TIFF file) “Data Model” –Multiple simple models for the same arae

Model “A schematic description of a system, theory, or phenomenon that accounts for its known or inferred properties and may be used for further study of its characteristics” –American Heritage® Dictionary of the English Language An abstraction of something real. –Dr. Thomas Hobbs

Raster “Models” Topography: Elevation/depth, slope, aspect, contours Distance to water Pop. Density Temperature Precipitation Habitat

Vector “Models” Roads Streams Population of states Census.gov

Types of “Models” Binary/Boolean Models: –Only 0 or 1 –Masks Ranking Models: –Ordinal ranking of areas Continuous Models –Possible values are continuous over some range –Index Models: from 0 to 1 –DEMs –Etc.

Classification into Rankings Depth Classes Depth (Bathymetry) 164 to meters

Index Model Scale inputs from 0 to 1 Multiply together Can be weighted based on importance

Data Structure Defines the “structure” of the data A container for specific types of data Can contain data of different meanings For files, synonymous with “Format” Examples: –Shapefile: Point, Polyline, Polygon –TIFF: Raster –Text file: Tables –XML: Metadata

Data Model Defines the contents and meaning of the data Should be detailed enough for someone else to use the data Examples: –Tiger Census files –NHD watersheds –Landsat Image –GNIS Data –FGDC Metadata

Data Modeling

Esri Approach

Esri Data Models Administrative Boundaries Agriculture Basemap Biodiversity/Conservation Cadastre 2014 Defense/Intel Energy Utilities Environmental Regulated Facilities Historic Preservation Hydrographic/Navigation (IHO) Local Government Marine Petroleum Pipeline System Architecture Telecommunications Transportation Water Utilities Water Resources (Hydro, Groundwater) Forestry Geology Land Parcels

Graphic courtesy of Maidment et al., ArcHydro team

Arc Marine dusk.geo.orst.edu/djl/arcgis

Geodatabase Feature Class Geometries

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