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Slide 1
Slide 2
Geodatabases by Shawn J. Dorsch
Slide 3
Spatial Databases Part 2
Slide 4
Topics Definitions Spatial Database vs. Geodatabase Reference
Systems Types of Data Spatial Query Processing
Slide 5
Definitions Spatial Database a database that models space,
objects in space, or a combination of both. (Reainthong 3)
Geodatabase a specialized spatial database that deals specifically
with geographical data.
Slide 6
Whats the difference? A spatial database is used to store a
model of any objects within a space. Might store the components and
layout of a circuit board A geodatabase will hold data within the
reference of the world. Coordinates of a city, boundary of a state,
or shape of a river
Slide 7
Spatial Reference System A projection of the real world into a
dataset that defines how spatial data is related. World Geodetic
System (WGS84) one of the most used geographical reference systems.
The Earth is a sphere so it cannot be projected with 100% accuracy.
http://spatialreference.org/
Slide 8
GIS and Geodatabases GIS is software that allows the data to be
visualized and analyzed. Search, perform calculations, analyze
results, and view statistics Geodatabases are one means by which
GIS can store and query the data. Also flat data files or
geo-raster files.
Slide 9
Types of Data Traditional data Non-geographical data Feature
data Data stored as points, lines, and areas Raster data Imagery
data that is geo-rectified.
Slide 10
Traditional Data IDAddrCityStateZip 1123 Main
St.SpringfieldIL50641 2554 Fake St.CressonPA15963 313 Cherry
Ln.AltoonaPA15904 Can be stored using a traditional DBMS Processed
with standard SQL
Slide 11
Feature Data IDAddrCityStateZipLocation 1123 Main
St.SpringfieldIL50641 2554 Fake St.CressonPA15963 313 Cherry
Ln.AltoonaPA15904 An object that stores a geographical
representation Uses vector geometry Good for objects with discrete
boundaries Streets, rivers, lakes, states
Slide 12
Feature Datatypes - (Shekhar and Sanjay 12)
Slide 13
Raster Data Imagery data Satellite imagery, Weather maps
Bitmaps, PNGs, JPEGs
Slide 14
How do we query a bitmap? Need to store geographical reference
data The coordinate system A reference point or x,y coordinate
typically the upper left or the lower left corner of the raster A
cell size The count of rows and columns
Slide 15
How do we query a bitmap? - (shown in ArcGIS Desktop Help)
Slide 16
Storage of Rasters CellShapeImageCorner 1 1.jpg Flat file uses
process called geotagging Add spatial reference as metadata Store
them in a geodatabase 2 methods: Store reference to the image file
Store image in the table CellShapeImageCorner 1
Slide 17
Spatial Queries Traditional query Find all the stores that sell
books on databases. Spatial query Find all the stores that sell
books on databases within 10 miles of zip code 15931.
Query Processing IDStoreNameLocation 1Store 1 Single stage
query: each tuple has to be accessed at most once. Find all the
stores within 10 miles of zip code 15931. ZipLocation 15931 spatial
query Stores Zips
Slide 20
Query Processing Multi stage query: The tuples are sent thru a
series of filter queries where each one reduces the size of the
result set. Each filter get increasingly more complex and more
costly. - (shown in Spatial Concepts)
Slide 21
Query Processing IDNameAddrLocation 1John Doe123 Main St Find
all store owners who live within ten miles of their store.
IDNameOwnerIDLocation 100Books R Us1 People Stores 1st Stage2nd
Stage
Slide 22
Indexing R-Trees like a B-tree, but for multi dimensional data
Splits data into a set of minimum bounding rectangles At each level
of the tree the rectangles get smaller Quad-Trees tree structure,
internal nodes have up to 4 children Regions are recursively split
into 4 quadrants that get smaller and smaller
Slide 23
Summary Geodatabases are a type of spatial database Data is
only meaningful in the context of a reference system Three types of
data Traditional, feature, and raster SDBMS runs queries in stages
to increase efficiency
Slide 24
Bibliography Shekhar, Shashi and Chawla, Sanjay. Spatial
Databases A Tour. Prentice Hall, 2003 Shekhar, Shashi and Chawla,
Sanjay. Chapter 2: Spatial Concepts and Data Models. Slides for
Spatial Databases: A Tour. Nov. 27,
2009.http://www.spatial.cs.umn.edu/Book/slides Gting, Ralf Hartmut.
An Introduction to Spatial Database Systems. dna.fernuni-hagen.
Sept. 1994. Nov. 27,
2009.http://dna.fernuni-hagen.de/papers/IntroSpatialDBMS.pdf
Welcome to ArcGIS Desktop Help 9.2. ArcGIS Desktop Help 9.2. March
15, 2007. Nov. 27,
2009.http://webhelp.esri.com/arcgisdesktop/9.2/index.cfm?TopicName=welcome
Object Modeling and Geodatabases. University of Texas at Austin
Center for Research in Water Resources. July 23, 1995. Nov. 27,
2009.http://www.crwr.utexas.edu/giswr/resources/library/ch01.pdf
Spatial Concepts. Oracle Spatial User's Guide and Reference. Nov.
27,
2009.http://download.oracle.com/docs/cd/B19306_01/appdev.102/b14255/sdo_intro.htm#BAJD
IHJF Reainthong, Tyler. Spatial Database Systems. CSE 5330/7330
Fall 2009 FILE ORGANIZATION AND DATABASE MANAGEMENT. Nov. 27,
2009.http://www.lyle.smu.edu/~mhd/7330f09/reainthong.pptx