NSF DUE ; Laura Johnson Cherie Aukland

NSF DUE ; GeoTEd Partners

NSF DUE ; Module Outline Modeling basics Data models overview CAD Coverage Geodatabase Basics of relational databases Data management techniques

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Modeling Spatial Reality Taking reality and placing it in a digital model Simplifying of real objects Determining map use Will guide model choice Many ways to represent or “model” the same object Example: highways

NSF DUE ; Modeling Highways As a series of mile marker points As a network of interconnected lines

NSF DUE ; Modeling Highways As areas with changing width As elevation features of differing grade from the surrounding terrain

NSF DUE ; GIS Data Types Points Schools, Tourist attractions, Wellheads Lines Streams, Roads Areas States, Census tracts, Bodies of water Surfaces Elevation, precipitation, temperature

NSF DUE ; GIS Data Representation Points Lines Areas VectorRaster

NSF DUE ; Data Models History of data models CAD data model Coverage data model Geodatabase data model

NSF DUE ; CAD Data Model Started in the 1960’s and 1970’s Usually vectors Points, lines, and areas Little attribute information stored Still used today for engineering drawings

NSF DUE ; Coverage Data Model ESRI started in 1981 Spatial data combined with attribute data Data stored in tables Tables can be customized Allows for topology Interconnectivity between features Features have generic behavior E.G., All lines behave the same way

NSF DUE ; Coverage Structure Image from libinfo.uark.edu

NSF DUE ; Geodatabase Data Model Object-oriented Define relationships and behaviors of features Allows for more detail Two types: Personal Geodatabase (1 st ) – up to 2GB, Access file File Geodatabase (2 nd )(recommended) – up to 1 TB, file folder Can be integrated with coverage data

NSF DUE ; Geodatabase structure Image from libinfo.uark.edu Geodatabase Feature dataset Feature classes Relationship class

NSF DUE ; What is a Geo Database? A geographically enabled set of data A relational database A convenient packaging tool for sharing and storing data

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Databases Tables are the building blocks of a database Parts of a table: Rows = records Columns = attributes or fields

NSF DUE ; Parts of a table FIDTractNameTractAreaPop 001CityPark TreeStreets GolfCourse3298

NSF DUE ; What Is A Database? A collection of related data Also called Relational Database Data stored in related objects Objects in Traditional database: Tables Forms Reports Queries Primary field Key field

NSF DUE ; Relational Databases RDBMS Relational database management system Uses key fields to link related objects and tables Creates Queries Reports Think Microsoft Access databases

NSF DUE ; Object-oriented Database An RDBMS, taken one step further, that allows us to: Specify how features interact Specify how features can be created Specify how features are to be displayed Interact with data directly (“hot links”) Geodatabases are object-oriented

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What makes GIS databases different? Data Types Must store spatial information and tabular data Data Storage Spatial data can be very large Good management is key End Users Not all users are GIS specialists Not all users will know what GIS is or how data was created

NSF DUE ; Special Techniques Database management Key due to large file sizes Look for key fields (“linkable” fields) Multiple smaller tables or feature classes better than one large one Less space Easier to navigate Less superfluous information

NSF DUE ; Additional tips and tricks Set up working GIS data directories as a sub-folder of a drive Example: C:\\GIS_Data\ NOT the My Documents folder In a new Map Document, go to File -> Properties first Set up relative path names Set up default Geodatabase for this map

NSF DUE ; Additional tips and tricks Name new output files logically and consistently! Delete unnecessary, erroneous, or duplicate feature classes/shapefiles after analysis

NSF DUE ; Questions?