topologi cal data models and structures
DESCRIPTION
Topologi cal Data Models and Structures. A major distinction among different vector data models is between those that have used a path topological approach versus those that have used a graph topological approach. - PowerPoint PPT PresentationTRANSCRIPT
TopologiTopological Data Models cal Data Models and Structuresand Structures
A major distinction among different vector data models is between those that have used a path topological approach versus those that have used a graph topological approach.
Today most vector models are a hybrid of both as path topological models became a subcomponent of the other.
Path Topological Models (1)Path Topological Models (1)
• Spaghetti Model(x1,y1)
(x2,y2)
(x3,y3)
(x4,y4)
(x5,y5)
(x6,y6)
(x7,y7)
(X8,y8)
(x9,y9)
(x10,y10)
(x11,y11)
(x12,y12)
(x13,y13)
(x14,y14)
String Coordinate List
S1 (x1,y1), (x2,y2), (x3,y3), (x4,y4),
(x5,y5), (x6,y6), (x7,y7), (x8,y8),
(x9,y9), (x10,y10), (x11,y11), (x12,y12)
S2 (x3,y3), (x13,y13), (x14,y14)
(x5,y5), (x14,y14), (x9,y9)S3
P1
P2
P3
(x1,y1)
• Polygon Model
Path Topological Models (2)Path Topological Models (2)(x1,y1)
(x2,y2)
(x3,y3)
(x4,y4)
(x5,y5)
(x6,y6)
(x7,y7)
(X8,y8)
(x9,y9)
(x10,y10)
(x11,y11)
(x12,y12)
(x13,y13)
(x14,y14)
P1
P2
P3
Polygon Coordinate List
P1(x1,y1), (x2,y2), (x3,y3), (x13,y13),
(x14, y14), (x9, y9), (x10,y10), (x11,y11),
(x12,y12), (x1,y1)
P2 (x3,y3), (x4,y4), (x5,y5), (x14,y14),
(x13,y13), (x3,y3)
P3 (x5,y5), (x6,y6), (x7,y7), (x8,y8),
(x9,y9), (x14,y14), (x5,y5)
The Slivering ProblemThe Slivering Problem
Polygon A
Polygon B
Path Topological Models (3)Path Topological Models (3)• Ppoint Dictionary Model
(x1,y1)(x2,y2)
(x3,y3)
(x4,y4)
(x5,y5)
(x6,y6)
(x7,y7)
(X8,y8)
(x9,y9)
(x10,y10)
(x11,y11)
(x12,y12)
(x13,y13)
(x14,y14)
P1
P2
P3
Polygon Point List
P1
P2
P3
p1, p2, p3, p13, p14, p9, p10,
p11, p12, p1
p3, p4, p5, p14, p13, p3
p5, p6, p7, p8, p9, p14, p5
Point Coordinate
p1 (x1,y1)
p2
p14
(x2,y2)
(x14,y14)
..
....
Path Topological Models (4)Path Topological Models (4)• CChain/Point Dictionary Model
P1P2
P3
Polygon Chain List
P1
P2
P3
C1C2
C3
C4
C5
C6
C1, C2, C3
C4, C5, C2
C6, C3, C5
Chain Point List
C1 p9, p10, p11, p12, p1, p2, p3
C2 p3, p13, p14
···
···
C6 p5, p6, p7, p8, p9
Point file necessary
Graph Topological modelsGraph Topological models• DIME (Dual Independent Map Encoding)
File and a DIME segment
p1 p2
Tract 101
Tract 102
From Endpoint p1
To Endpoint p2
Left Tract 101
Right Tract 102
DIME Model of a MapDIME Model of a Map
P1P2
P3
L1
L2
L3
L4L5
L6
L7
L8
L9
L10L11
L12
L13
L14
L15
L16
Line
Segment
From
Point
To
Point
Left
Polygon
Right
Polygon
L1 p9 p10
P4
P4 P1
L2 p10 p11 P4 P1
···
···
··· ···
···
L7 p3 p4 P4 P2
L8 p4 p5 P4 P2
L9 p5 p6 P4 P3
L10 p6 p7 P4 P3
L11 p9 p8 P3 P4
···
···
···
···
···
L16 p13 p3 P1 P2
Point file necessary
Retrieval from DIME Structure Retrieval from DIME Structure (1)(1)
P1P2
P3
L1
L2
L3
L4L5
L6
L7
L8
L9
L10L11
L12
L13
L14
L15
L16
P4Stage 1 – Retrieve all segments belonging to P3
L9
Seg. No.
From To Left Right
L10
L11
L12
L13
L14
p5 p6 P4 P3
p6 p7 P4 P3
p9 p8 P3 P4
p8 p7 P3 P4
p9 p14 P1 P3
p14 p5 P2 P3
Point file necessary
Retrieval from DIME Structure Retrieval from DIME Structure (2-3)(2-3)
P1P2
P3
L1
L2
L3
L4L5
L6
L7
L8
L9
L10L11
L12
L13
L14
L15
L16
P4Stage 2 – Reorder the segments for path topology
L9
Seg. No.
From To Left Right
L10
L11
L12
L13
L14
p5 p6 P4 P3
p6 p7 P4 P3
p9p8 P3P4
p8p7 P3P4
p9 p14 P1 P3
p14 p5 P2 P3
Point file necessary
POLYVRT SystemPOLYVRT System
P1P2
P3
P4
C1
C2C3
C4
C5C6
ChainFromNode
ToNode
LeftPolygon
RightPolygon
C1 N1 N2 P4 P1
C2 N2 N4 P2 P1
C3 N2 N3 P4 P2
C4 N3 N1 P4 P3
C5 N1 N4 P1 P3
C6 N4 N3 P2 P3
Point list for each chain necessary, a polygon file (circular list of chains) recorded
N1
N2
N3
N4
Node ModelNode Model
P1P2
P3
P4C1
C2C3
C4
C5
C6
N1
N2
N3
N4
NodeCobounding
Chains
Right-hand
Polygons
Adjoining Nodes
N1
N2
N3
N4
C4 C5 C1 P4 P3 P1 N3 N4 N2
C2 C3 C1 P1 P2 P4 N4 N3 N1
C6 C4 C3 P2 P3 P4 N4 N1 N2
C6 C2 C5 P3 P2 P1 N3 N2 N1
Polygon Node
P1 N1
P2 N2
P3 N3 Chain file containing its list of points necessary
Four Corner SituationFour Corner Situation
UT CO
AZ NM
N
UT CO
NMAZ
N
N’
Extended Chain ModelExtended Chain Model
P1P2
P3
P4C1
C2
C3
C4
C5C6
N1
N2
N3
N4
ChainFrom Node
To Node
Left Polygon
Right Polygon
Left Chain
Right Chain
C1 N1 N2 P4 P1 C4 C2
C2 N2 N4 P2 P1 C3 C5
C3 N2 N3 P4 P2 C1 C6
C4 N3 N1 P4 P3 C3 C5
C5 N1 N4 P1 P3 C1 C6
C6 N4 N3 P2 P3 C2 C4
A polygon file containing the ID of one chain on its boundary and a chain file containing its list of points are recorded
PAN GraphsPAN Graphs
P
A N
P
A N
( a ) ( b )
Questions for ReviewQuestions for Review• Please understand the spaghetti model,
polygon model, point dictionary model and chain/point dictionary model of the data structures and their respective advantages and disadvantages.
• Compare the DIME and POLYVRT file structures and their advantages and disadvantages.
• Describe the process of the retrieval of the outlines of polygons using the node model and the extended chain model.