The Geodatabase Chase T. Brooke Ecosystem Science and Management Texas A&M University College StaOon, TX 77843 cbrooke@tamu.edu
EvoluOon of the acronym GIS
SpaOal Thinking IdenOfying, analyzing, and understanding the locaoon, scale, pazerns, and trends of the geographic and temporal relaoonships among data, phenomena, and issues. - Joseph Kerski
SpaOal Thinking What is your definioon of spaoal thinking?
What is a Geodatabase? A spaoal relaoonal database management system that stores geographic and related data. Central repository for spaoal data storage and management.
EvoluOon of database systems
Geometry Data Type All 2D mapping can generally be accomplished with three geometry types Points, polylines, and polygons
RelaOonships among features Topological Determines adjacency and connecovity among features Shared and coincident geometry types SpaOal Network Simple edges and juncoons Complex edges and juncoons General
Topology
Geometric Network The storage of network informaoon Several components Simple edges and juncoons Complex edges Complex juncoons
Geometric Networks To build a network Sources and sinks ConnecOvity rules Edge- juncoon rules Edge- edge rules Perform a network analysis Trace Flow direcoon
The parts of a geodatabase Geographic dataset Feature classes, a collecoon of features with the same type of geometry RelaOonship classes, a table that stores the relaoonships between two feature classes Object classes A feature class table A non- spaoal azribute table
The parts of a geodatabase
Example Geodatabase
Making your own geodatabse Design your data model Evaluate your data Define database structure Add data Understand your spaoal reference Choose a coordinate system SpaOal domain Precision Modify your spaoal domain if necessary
Benefits of using a geodatabase Store a rich collecoon of spaoal data in a centralized locaoon Apply sophisocated rules and relaoonships to the data Define advanced geospaoal relaoonal models (e.g., topologies, networks) Maintain integrity of spaoal data with a consistent, accurate database
Benefits of using a geodatabase Work within a mulouser access and ediong environment Integrate spaoal data with other IT databases. Easily scale your storage Support custom features and behavior
Two types of Geodatabes in ArcGIS
Personal geodatabase May be read by mulople people Only edited by 1 person at a Ome Max size 2 GB Currently stores only vector data Raster stored as catalogs
MulO- user geodatabase Suitable for large workgroups and enterprise GIS implementaoons May be read and edited by mulople users simultaneously Requires ArcSDE and a DBMS Supports both raster and vector formats
A geodatabase extends a database Provides the framework for defining and managing the GCS for a set of data Models topologically integrated sets of feature Defines general and arbitrary relaoonships between objects and features
A geodatabase extends a database Enforces the integrity of azributes through domains and validaoon rules Binds the natural behavior of features to the tables that store features Stores mulople versions so that many users can edit the same data
SpaOal Query What is a spaoal query? Name three examples of a spaoal query
SpaOal Query OperaOons Search ThemaOc search Search by region Search by classificaoon LocaOon analysis Buffer Corridor Overlay
SpaOal Query OperaOons Terrain analysis Slope/aspect Catchment Drainage network Flow analysis ConnecOvity Shortest path
SpaOal Query OperaOons DistribuOon Change detecoon Proximity Nearest neighbor SpaOal analysis/staosocs PaZern Centrality AutocorrelaOon Indices of similarity Topology Hole descripoon
SpaOal Query OperaOons Measurements Distance Perimeter Shape Adjacency DirecOon
Architecture of a SpaOal Database
Core features of a DBMS Persistence Some data are transient Some are persistent TransacOons Map a database from one consistent state to another All or abort Many transacoons executed concurrently
Space Taxonomy OrientaOon, DirecOon, Topological relaoonships (adjacent, next to, inside) MulOtude of descripoons available to organize space
Data Model Vector Points Polylines Polygons Fields Raster, uniform grid imposed on underlying space TIN, triangulated irregular networks Contour lines Point grids
Data Model Example
Data Model Example
Data Model Example
Structured Query Language (SQL) DeclaraOve language User specifies the result Example: Find all land parcels next to my house. SELECT M.address FROM land_parcel L, city_name M WHERE Adjacent (L,M) AND M.address = MYHOUSE
Types of queries Range (select all points within 10 km of the city limits) Join (combine two tables on a common azribute)
SQL Examples Join SpaOal Join
File organizaoon and indices Programmer s Point of View Database Manager s Point of View Finite Infinite Infinite
Data mining SystemaOc search of potenoally useful informaoon embedded in digital data Hot topic of research inside and outside of academia BIG DATA
Big Data Landscape
Ecosystem Science and Management Texas A&M University (c) 2014, A. Michelle Lawing SpaOal data are Big Data ESSM/GEOG 462: Advanced GIS
SpaOal data mining Find pazerns in data with respect to geography Not new in GIS, but methods are soll in their infancy Up to 80% of digital data is spaoal in nature!
SpaOal data mining A spaoal database specialist can leverage experose to Design search algorithms to hand large amounts of data Extend SQL with mining methods Random sampling commonly used in data mining Because of spaoal autocorrelaoon, other techniques might need to be employed (spaoal staosocs)
SpaOal databases Important for management of spaoal and related data Important for the query of spaoal data to extract both spaoal and related data