Accelerating Queries on Very Large Datasets - Scientific Data Management - page 199

Linear Linear Binary

Y X Label Quad-Code Gray-Code

y0 x6 A 110 010001 ⇒ 30

y2 x6 B 130 011011 ⇒ 18

y4 x3 C 211 101100 ⇒ 55

y5 x3 D 213 101110 ⇒ 52

y2 x1 E 021 001011 ⇒ 13

y4 x1 F 201 101001 ⇒ 49

y1 x7 G 113 010010 ⇒ 28

y2 x5 H 121 011111 ⇒ 21

y1 x5 I 103 010111 ⇒ 26

y6 x4 J 320 110110 ⇒ 36

y7 x2 K 232 100101 ⇒ 57

y6 x7 L 331 110010 ⇒ 35

y5 x2 M 212 101111 ⇒ 53

y3 x0 N 023 001000 ⇒ 15

⇒

y4 x5 N 301 111101 41

Figure 6.7 A sample multiattribute data.

give rise to the numerous multidimensional indexing methods described in the
literature. For example, the tessellation of the data space may be

overlapping or non-overlapping,

flat or hierarchical, and

based on equalizing the points in each region as much as possible or
based on generating equal regions of spatial extents.

x0 x1 x2 x3 x4 x5 x6 x7

A

y0

G

I

y1

H

E B

y2

N

y3

F

C

O

y4

MD

y5

J

L

y6

K

y7

Figure 6.8 Multi-attribute data in 2D space.