john pickford ibm

John PickfordIBM

H11

Wednesday, October 4, 2006 • 13:30. – 14:30.

Platform: Informix

Practical Applications of IDS Extensibility (Part 2 of 2)

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Key Points

• What is Spatial Data

• Spatial coordinate systems

• What is the Spatial Datablade

• What are Spatial Applications

• Other uses

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What is Spatial Data ?

• Data related to a location• Location• Data relating to that location or a set of

locations

• Location is specified as a point on a co-ordinate system• Flat Earth• More realistic shaped Earth

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Spatial co-ordinate systems

• Flat Earth• Conic

• A portion of the Earth's surface is projected onto a cone. The cone is then flattened

• Mercator• The Earth's sphere is

flattened out. In this projection the further away from the axis a point is, the larger it seems

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• Geodetic Data• Points specified by

longitude and latitude

• Much more complex• what is a straight line ?• what is the distance

between 2 points ?longitude

latitude

0-90

(90° W)

+90(90° N)

R

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Where is Spatial Data Used ?

• Geographical Information Systems (GIS)• Store spatial data• Analyse spatial data• Display spatial data

• Could be used in CAD/CAM

• Others ?

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What is the Spatial DataBlade ?

• Some data types• Basic type is a point

• x and y•co-ordinate system

• z (optional)• m (optional)

• Spatial types• Point(s)• Line(s)• Polygon(s)

• Some functions• Standard OGC

functions• Additional functions

• Support for different co-ordinate systems

• Spatial Index Support

• Some utilities• Load shapes

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Spatial Data Types

• Point(s)

• Line(s)• They can cross (themselves and

each other)

• Polygon(s)• A polygon must have the same

start and end point• They can not cross themselves or

each other but can touch

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Spatial Data Types

• Each point can have• A z co-ordinate (height, depth, …)• A measure (e.g. time)

• The 'measure' can be interpolated

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Spatial Functions

• Convert geometries from/to:• Text• Well Known Binary (WKB)• ESRI Shape files

• Convert geometries to:• GML

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Spatial Functions• Get parameters

• Dimensions of coordinates and geometry• Data type• Number of points• SRID• Max/Min of x, y, z, m

• Manipulation• Get the x, y, z, m of a point• Get the first, mid, nth, last point of a line• Get the area, centre, perimeter• Get the nth geometry in a in a "multi"

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Spatial Functions

• Relationships between geometries:• Contain each other• Cross• Intersect• Overlap• Touch• Disjoint• Equal

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Spatial Functions

• Create new from existing:• Union• Intersection• Difference• Perpendicular projection• Buffer• Boundary• Envelope• Generalize

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Spatial Functions

• Nearest neighbour

• SRID management• Get the SRID of a geometry• Transform from one SRID to another

• Administration• Get sizes

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Spatially Enabling a Database

• Two easy steps:• Get the spatial DataBlade• Use "Blade Manager" to add it to the database

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Inserting Spatial Data

• Create table with spatial columncreate table gpsDemo

(seRowId char(10), path st_linestring);

• Insert datainsert into gpsDemo values ('a',

st_linefromtext('linestring zm(

0. 0. 0. 100, 1. 1. 0. 110,

2. 2. 0. 120, 3. 3. 0. 130

)', 4));

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Selecting Spatial Data

• Select:select * from gpsDemo;

seRowId path

a 4 LINESTRING ZM (0. 0. 0. 100, …..

select seRowId, st_envelope(path) from gpsDemo;

seRowId path

a 4 POLYGON ((0. 0., 3. 0., 3. 3., …..

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Evolution of GIS Data Management

GIS Application

GIS Application

SQL

Proprietarydata format1st Generation:

2nd Generation:

3rd Generation:SQL

ProprietaryGIS API

ProprietaryGIS APIGIS

Application

GIS Application

GIS

Application

GIS

Application

FileSyste

m

FileSyste

m

GIS Data

Engine

GIS Data

Engine RDBMSRDBMS

“Spatial” Application

“Spatial” Application

Spatially enabled DBMS

Spatially enabled DBMS

RDBMSRDBMSSQL

Spatial features, indexes in

BLOBs

Attributes

GIS Data

Engine

GIS Data

Engine

Spatial types functions indexes

Spatial Features

Proprietaryspatial

structures

Open or proprietary

Open

Spatial business logicSpatial business logic

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App ServerApp ServerExtensibleRDBMS

ExtensibleRDBMS

Spatial dataSpatial data

Data Business Logic

Client

HTTP

Serv

er

HTTP

Serv

er

Thin-Client

Bro

wser

Bro

wserIntran

et Intern

etEJBsEJBs

CorporateApplications

CorporateApplications

Java App

Java App

Java App

Java App

Java App

Java App

WebService

WebService

WebService

WebService

Service

ExtensibleRDBMS

ExtensibleRDBMS

Spatial dataSpatial data

Service-Oriented Architecture

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DataBlade Component Technology

ConnectivityConnectivity BackupBackup RestoreRestoreServer SubsystemsServer Subsystems

DB2/IDSDB2/IDSDB2/IDSDB2/IDSSpatialGeodetic

GridYour idea goes here

SpatialGeodetic

GridYour idea goes here

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DataBlade Elements

TypesTypes

FunctionsFunctions

CastsCasts

AggregatesAggregates

IndexesIndexes

TablesTables

Client CodeClient Code

New New Extender/Extender/DataBladeDataBlade

New New Extender/Extender/DataBladeDataBlade

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R-Tree Indexing

• Not part of the Spatial Datablade but key to Spatial Data Management

• Index still organised as a tree structure but they point to Regions

• Not limited to 2 dimensions

Root

Branch Branch Branch

Leaf Leaf

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R-Tree indexing

• Not limited to spatial data

• Consider times and time periods

Y

X

Start time

End time

Time period

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Spatial Clients

• There are different ways to access the data from a client program• Java Class Library• ESQL/C• ODBC/JDBC

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Server Access

• Spatial data can be access in the server• SPL• UDF

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A mini Spatial Application

• A small demo to show how spatial data can be stored and displayed• Base GIS demo data distributed free with the datablade

as ESRI shape files• Data loaded into IDS tables using the loadshp program• Data read as GML into a php script started by accessing

the php file from a browser (Firefox 1.5.0.4 with xfrorms extension)

• GML data transformed to SVG and display as graphics

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A mini Spatial Application – Results

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lat long Speed Dir Time

-2.20214 51.87797 3.8 54.1 00:00

-2.20196 -51.87807 4.6 57.2 00:10

2.20176 51.87816 5.7 57.6 00:20

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John PickfordIBM

[email protected]

H11Practical Applications of IDS Extensibility (Part 2 of 2)

john pickford ibm

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