Database Support for Temporal 3D Data: Extending the GeoToolKit

© 2001 Institut für Informatik III, Universität Bonn

Database Support for Temporal 3D Data:

Extending the GeoToolKit

Serge Shumilov

Jörg Siebeck

Institute for Computer Science III

University of Bonn

Tel. +49 (02 28) 73-45 35

Fax +49 (02 28) 73-43 82

[email protected]

[email protected]

© 2001 Serge Shumilov & Jörg Siebeck Database Support for Temporal 3D Data 2

Previous Experience: Balanced Restoration of Structural Basin Evolution

Three time steps of the basin modeling in the Lower Rhine Basin: view from the southern part to north-east with the Oligocene bases and the antithetic faults


Geometry changes...

Example for the change of the geometry:part of the Oligocene of the Lower Rhine Basinabout 6, 9 and 13 million years ago, visualized with GRAPE


Geometry Approximation as well...

Example for the change of the topology (discretization):part of the Oligocene of the Lower Rhine Basinabout 28 million years ago, visualized with GRAPE


Localization of changes in topology

time

-20

-10

0

earth surfacefault

changes only in geometry


Conceptual Model of 4D Data


Design Objectives

Allow a smooth animation on time intervals

States in between can be interpolated

Build dynamic data structures

Insert, Delete, Update operations on 4D geometries

Supports geological modelling

Separate meshes and vertices

Build several meshes from one set of vertices

Automatic consistency w.r.t. vertices

Extend 3D data types with time

Coherence


Extending the 3D Conceptual Model with Time-Moving Vertices-

Time isomorphic to the reals Location and shape of geometries

is a function of time

Vertices move on their trajectories

In our model: Trajectory piecewise linear

Change in direction => Snapshot

Linear interpolation also w.r.t. time

=> const velocity/no acceleration

Change in velocity => Snapshot

)(|)()( vv locdefttlocvtraj )(|)()( vv locdefttlocvtraj

x

y

t3010 2015

interpolated


Moving Complex Types

Assemble complex geometries from moving vertices Separates meshes from vertices

A moving simplex comprises: References to its moving vertices

Temporal interval of validity

A moving complex comprises: Set of moving simplices

Temporal interval of validity

Integrity constraints!

Moving vertex

Moving vertices span a moving triangle


Representation of time-dependent simplicial complexes applying key-frame interpolation

t

points

p0

time

pNt0

t1

t2

same datadifferent discretisation

different datasame discretisation

added triangles

remained triangles

interpolated object

( t1 < tx < t2 ) tx

representation of moving 3D points

„post“ t0

deleted triangle

„pre“ t1

„post“ t1

„pre“ t2

...

txinterpolatedvalue

storedvalue


Internal Storage Representation


Why bothering?

Optimum for operations:

Store full extent for each time-step

Results in storing nt * T simplices

Optimal for space only, when discretization changes completely in each time-step

Optimum for storage space:

Store one set of moving simplices only

Time: Retrieving a time-slice results in examining nt * T simplices

Need a good compromise for

compact storage and

fast operations


Full Extents with Version Management (1)

. . .

full version delta version

. . . . . .

tt0 t1 tm-1 tm tm+1 tn-1 tntm+2

N t

k

tm tn-1tm+1 tm+2

k

tm+3


Full Extents with Version Management (2)

tt0 t1

. . .

tm-1 tm tm+1 tn-1

full version delta version

. . .

tn

. . .

tm+2

N t

k

tn-1

kN

tm tm+1 tm+2 tm+3


Comparison

N t

k

tn-1

kN

k

k

Im+1

Dm+1

Im+2

Dm+2

k

(k – kp)N

kp

kp

tm tm+1 tm+2 tm+3


Implicit Extents Utilizing Neighbour References

Stores only one ‘‘big‘‘ set of moving simplices

no full extents, no deltas

Keeps one entry point into the complex for each time-step

Maintains neighbour references

s


Using Neighbours for Implicit Time-Steps

t0 1 2

s s ss1 s

5

s4

s3

s1

s2

s3

e:[t0, t2]

s

[0, 2) : s1 [2, tx] : s4[0, 1] : null

(1, tz] : s5 [0, 1) : s2 [1, ty] : s3

Internal Representation of sInternal Representation of s


Basic Queries on Time-dependent Geometries

Time-step query

Given:

instant t, time-dependent geometry g

Retrieve a (3D) snapshot of a g at t

Time-interval query

Given:

temporal interval i, time-dependent geometry g

Retrieve a series of (3D) snapshots of g valid during i

Insertion/Deletion

Given:

time-dependent simplex s, time-dependent geometry g

Insert s into g / Delete s from g


Performance comparison (1)

time(s) nt logT(time(s)/N+log(T/N)+N) log(nt)

(time(s)/N+log(T/N)) log(nt)

Time

simplex operations

O(Nnt logT) ( kN + log(T/N), ½kN2 + log(T/N) )

kN + log(T/N)Time

interval query

O(nt logT)( ¼ kN + log(T/N), ½kN + log(T/N) )

½kN + log(T/N)Time

time-step query

(n+T) O(nT)( T(nt/N + k), T(nt/N + ½ kN)

T(nt/N + k)Space

Implicit time-step extents

Referencing

full version

Referencing

previous version


Performance comparison (2)

periodic changes

homogeneous changes

Referencingfull version

Implicit time-step extents

monotonic changes

Referencingprevious version


Evaluation


Evaluation Application

Sponsor: Deutsche Forschung Gemeinschaft (DFG) Collaborative research program SFB 350 Postgraduate curriculum GRK437 Landform

Project Participants: Workgroup of Prof. Dr. A. Siehl

SFB350 subproject C4

Dept. of Geology, University of Bonn

Workgroup of Prof. Dr. A.B. CremersSFB350 subproject D4, GRK subproject A4Dept. of Computer Science III, University of Bonn

Dataset: Rheinbraun AG

Open pit mine “Bergheim”


Position of the Bergheim mine within the Lower Rhine Basin


Open pit mine within the Lower Rhine Basin


Open pit mine with giant coal excavator no. 288


Bergheim open pit mine: Position of faults and cross sections

A digitized cross-section of the Mio-Pliozene strata of Bergheim open pit mine. The hatched areamarks the filled-up part of the mine.


3D model “Bergheim” in GOCAD

0,5 km


GeoToolKit object model

SpatialObject(SO)

methods:contains(SO):BOOLintersection(SO):SOdistance(SO):REALclone():SO

Space(S)

methods:insert(SO)remove(SO)retrieve(BB):Sadd_index(AM)

AccessMethod(AM)

methods:insert(SO)remove(SO)retrieve(BB):Set<SO>BoundingBox(BB)

methods:contains(BB):BOOLintersection(BB):BB

Tetrahedron

TetraNet

Solid

Box

Triangle

TriangleNet

Surface

Plane

Segment

PolyLine

Curve

Line

PointRep

Group

R*Tree OcTree

User-Defined Access Methods

User-Defined Spatial Objects

AccessMethodClass Hierarchy

SpatialObjectClass Hierarchy

GeoToolKit Kernel

0D 1D 2D 3D

representational data type

inheritance

1:1 relationship

1:n relationship

Point


Extending GeoToolKit's Class Model

TriangleNet

3D

SpatialObject(SO)

SpatialObjectClass Hierarchy

4D

TriangleNet4D

TriangleNetElement4D

NetManager4D

TNECluster4D

PointManager

PointRep

PointCluster

PointManager4D

PointCluster4D

PointRep4D

time

prev next

under developmentrepresentational data type

inheritance 1:1 relationship 1:n relationshipattribute

NetManager

TriangleNetElement

TNECluster

Geometry Managenemt

Topology Managenemt


Database model of the Lower Rhine Basin


GeoStore

GeoToolKit

Adapter

GeoClient

Communication Infrastructure

GOCAD

VRML

Bus

3D/4D Database

Platform-independentExtensible Client-Integrator

DistributedGeoscientificTools andApplications

Communication Infrastructure


CORBA-based integrated architecture

GeoStore

transient mediator

CORBA-based communication bus

Geo-Applications

JavaClient

GeoToolKit

persistentobject

XDA Adapter

„proxy“objekt GOCAD


Application

GeoStore

Remote access to spatial data

GOCADJava-Client

3D modeling and visualization tools

Database exploration and

querying interface VRML


Special-purpose Java-Client


Visualization of the 4D model in VRML browser

t = 0

t = -10

t = -30


Conclusion and Future Work

Conclusions

Need for spatio-temporal database types

Conceptual model of spatio-temporal data adequate for our applications

Solutions to storage problem provide compromise between time/space

Based on version management

Based on implicit time-step extents

Applications

Future Work Extend conceptual model: operations on spatio-temporal types Information infrastructure New applications (kinematics of landform)


Contact information

Department of Computer Science III,University of Bonn, Germany

http://www.geo.cs.uni-bonn.de/

GeoToolKit

http://www.geo.cs.uni-bonn.de/software/geotoolkit

XDA

http://www.geo.cs.uni-bonn.de/software/xda

Documents

Database Support for Temporal 3D Data: Extending the GeoToolKit