1 / 30

Intro to GIS | Summer 2012 Attribute Tables – Part 1

Intro to GIS | Summer 2012 Attribute Tables – Part 1. DATABASES. Why do we care about Databases?. Integrated sets of data Focused on a particular area and subject Form the basis of GIS analysis and decision-making

marcia-wade
Télécharger la présentation

Intro to GIS | Summer 2012 Attribute Tables – Part 1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Intro to GIS | Summer 2012 Attribute Tables – Part 1

  2. DATABASES

  3. Why do we care about Databases? • Integrated sets of data • Focused on a particular area and subject • Form the basis of GIS analysis and decision-making • Must be well-structured in order for us to best access the information stored in them

  4. How are Databases Managed? • Database Management System (DBMS) = system or software program(s) that enables you to store, modify and extract information from a database

  5. Relational Database (RDBMS) • Supports the representation of data as a set of tables that are related to each other • Each table = a list of records containing attributes about features • Tied together by a “Attribute Key” = an attribute field common to both tables

  6. Table Data Structure Record: a row in a database; represents one feature (a.k.a. “tuple”) Attribute: a column in a database; contains attribute values (a.k.a. “field”)

  7. Which attribute field is the Attribute Key in this case?

  8. Object (ODBMS) & Object-Relational (ORDBMS) Databases • ODBMS = Supports the representation of data as objects having attributes, methods and behavior • e.g. ArcGIS geodatabases • Designed to address the weaknesses of RDBMS such as: • Geometry and attribute data are stored in separate databases • Poor performance for many types of geographic query • Geographic extensions to standard RDBMS can provide similar functionality (ORDBMS)

  9. GEOGRAPHIC (SPATIAL) DATABASES

  10. What is a Geographic (Spatial) Database? • Contains one or more tables with a geographic component (a “shape” attribute) • Common example: an ESRI Geodatabase

  11. Features can be: Constrained (domains) Validated by rules Modeled with complex behavior ESRI Geodatabase Features have: • Shapes • Attributes • Spatial Reference • Relationships

  12. ESRI Geodatabase

  13. Types of Geodatabases Personal • Single-user • Microsoft Access • Up to 2 GB storage File • Single-user • File folder structure • Up to 1 TB storage ArcSDE • Multi-User, supports versioning • Oracle, Microsoft SQL Server, IBM DB2, IBM Informix, PostgreSQL • Storage limit based on DBMS type ESRI Comparison of Geodatabases

  14. “Default” Geodatabase • A setting in ArcGIS • Helps with data management • Allows you to: • Store all datasets in one convenient location, or • Set a database for each project

  15. Setting the Default Geodatabase - ArcMap

  16. Change location of Default Geodatabase

  17. Setting the Default Geodatabase – ArcCatalog

  18. QUERYING GIS DATA

  19. Getting Information from GIS data • Query = to question or inquire about a feature(s) shown on a map (and by extension, in a GIS dataset) • Output is a selected set of records • Two approaches: • Attribute queries • Spatial queries

  20. Attribute Queries • Selects features based on non-spatial information in an attribute table • e.g. Which counties in the US have > 100,000 people? • “Select By Attributes” tool in ArcMap • SQL (structured query language) used to write query

  21. Spatial Queries • Selects features based on location or spatial relationship between data layers • e.g. Which Oregon counties have an interstate highway passing through them? • “Select Layer by Location” tool in ArcMap • Target layer = base layer; contains features you want selected • Filter layer = comparison layer • What kind of spatial relationships are possible between points, lines and polygons?

  22. “Add XY Data” tool

  23. Bakery list – Excel file

  24. New Point Layer for Bakery Locations

More Related