--------------------------
BQ GIAO DUC vA DAo TAO
TRUONG DHDL NGO~I NGU-TIN HQC TP.HCM
KHOA CONG NGH:'::THONG TIN
,
.-..
~
..-...
KHOA LUAN
TOT NGHIEP
•
•
NGHIEN cUu MOT s6 GIAI THUAT xAY DuNG LU01
TAM GIAC, UNci Dl)NG GIAI THU~T DE xAy DljNG
BAN DO DIA
HINH vA GIAI cAc BAI ToAN CHONG
•
LOP THONG TIN
GIANG VlEN HUONG DAN: Th.S NGUYEN MINH NAM
SINH VrEN THVC HI:'::N: D~NG CONG BINH
PH~M VAN DAN PHUONG
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TP.HO CHi MINH - 2005
LOIMOnA.U!
Chung em xin chan thanh cam an Th.S Nguy~n Minh Nam da: t~ tinh
huang dful chung em hoan tftt d~ tai; cam an cac th~y co truemg Huflit da: t~n
tinh giang dc;1Y, huang dful va giup do chung em trong qua trinh hQc t~p va
lam bao cao.
1
Ml)C Ll)C
LOIMODAu
Ml)C U)C
DANH Ml)C KY HIJ;:U VIET TAT
DANH Ml)C cAc HiNH VE
CHVONG 1 - GIOI THIJ;:U
1.1 D6i tm;mg va ph
1.2 Y nghia khoa hoc
. va thuc
. ti~n:
1.3 M\lC dich clla vi~c nghien Clm:
1.4 Huang ti~p c?n:
1.4 K~t lU?n:
CHVONG 2 - TONG QUAN VE HJ;:THONG THONG TIN DIA LY
2.1 Gim thi~u
2.2 Ban d6
2.2.1 Cac lot;tiban d6
2.2.2 Cac d~c di~m clla biin d6
2.2.3 Thong tin tren biin d6
2.3 Gi6i thi~u v~ Raster va Vectof.
.;;:'
• '"
.,
~
,
b.It tren
" may
, tl'00
2.3.1 Bleu
dlen
ban
doA bang
cac
2.3.2 Dfr li~u Vector ( Vector Data )
2.3.3 Dfr li~u Raster(Raster Data)
2.4 Topology
2.5 Dfr li~u dia ly ( Geographical Data, Geospatial Data)
2.6 DiOOnghia h~ th6ng thong tin dia ly (Geographical Information Systems - GIS)
2.7 Thu th~p cac ngu6n dfr li~u Clla h~ th6ng thong tin dia ly
2.7.1 Phuong phap quet ( Scanning ):
2.7.2 Phuong phap s6 hoa (Digitising):
2.7.3 Phuong phap vector hoa (Vectorisation):
2.8 Cac tmg d\lng Clla h~ th6ng thong tin dia ly trong cUQcs6ng
2.8.1 Sv nguy hi~m Clla nu6c tri~u len
2.8.2 Cac dich V\l khAn cAp:
2.8.3 Sv 0 OOi~mti~ng 6n a san bay:
2.8.4 Phan dch mt;lllg:
'"
2.8.5 Web Gis:
,
2.8.6 Mobile Gis:
2.9 K~t lu?n
CHVONG 3-TONG QUAN VE THUAT ToAN TAO LlJOI TAM GIAC
3.1 Mo ta Thu~t toan chiOO:
3.1.1 DiOONghia
3.1.2 Di~u Ki~n
3.1.3 Vi d\l
3.1.4 Thu~t toan Delone
3.2 Cac du truc dfr li~u duqc su d\lng:
3.2.1 Mo hiOOtopology
3.2.2 Xay dvng cac cAu trUc
3.2.3 K~t lu?n
1
1
1
1
3
3
.4
4
4
4
5
5
6
.6
6
7
7
8
8
8
8
9
9
9
9
10
10
11
12
12
13
14
14
14
14
15
15
16
16
17
19
3.3 K~t lu~
CHlfONG 4 - HIBN THVC THUAT ToAN
4.1 Tim bao 16i:
4.1.1 Dinh nghia
4.1.2 PhU011gphap tim bao 16i
4.1.2.1 Vet e~ (ban dAu)
4.1.2.1.1 PhU011gphap
4.1.2.1.2 Vi d\l
4.1.2.2 Vet e~ (cai ti~n)
4.1.2.2.1 PhU011gphap
4.1.2.2.2 Vi d\l
4.1.2.2 Chia d~ tri
4.1.2.2.1 PhU011gphap
4.1.2.2.2 Cac truang hqp
4.1.2.2.3 Vi d \l
4.1.2.3 PhU011gphap Melkman
4.1.2.3.1 PhU011gphap
4.1.2.3.2 Hi~n th\Ic
4.1.2.3.3 Vi d\l minh hQa
4.1.3 K~t lu~
4.1.3.1 Vu di~m va khuy~t di~m cua cae phU011gphap tim bao 16i
4.1.3.2 ThOi gian th\Ic hi~n cua cac phU011gphap tim bao 16i (eh~y ITch~ dQ Debug)
4.2. T~o lu61 TIN ban dAu:
4.2.1 Dinh nghia
:
4.2.2 Cae bUGe d~ t~o mQt lu61 Tin Sa Khai Ban DAu
4.2.3 Ap d\lng minh hQa
4.3 T~o Lu61 Tin Hoan Chinh:
4.3.1 Dinh nghia:
4.3.2 Cac bUGed~ t~o mQt lu61 Tin hoan ehinh:
4.3.3 Nhi'ing phU011gphap tim ki~m:
4.3.3.1 Phu011g phap vet c~ :
4.3.3.1.1 Mo ta
4.3.3.1.1.1 PhU011gphap
4.3.3.1.1.2 Danh gia
4.3.3.1.2 Vi d\l minh hQa
4.3.3.2 Phu011g phap dung Bang Bam:
4.3.3.2.1 Mo ta
4.3.3.2.1.1 PhU011gphap
4.3.3.2.1.2 Vi d\l
4.3.3.2.1.3 Danh gia
4.3.3 .2.2 Vi d\l minh hQa
4.3.3.3 RTree:
4.3.3.3.1 Gi61 thi~u
4.3.3.3.2 C~u true RTree
4.3.3.3.2.1 Dinh nghia eae cftu true dfr li~u:
4.3.3.3.2.2 Dinh nghia eay RTree:
4.3.3.3.2.3 Vi d\l:
19
20
20
20
20
20
20
23
32
32
34
41
41
42
42
43
43
43
44
51
51
53
53
53
54
54
60
60
60
60
60
60
60
60
61
61
61
61
62
62
63
63
63
64
64
65
65
4.3.3.3.3 Phuong phap tim Vt tri mQt di~m trong lum TIN bfulg RTree
66
4.3.3.3.4 K€t lu~
66
4.3.3.4 K€t lu~:
66
4.3.4 Phuong phap them di~m vao tam giac:
67
4.3.5 K€t lu~:
70
4.3.5.1Vu di~m va khuy€t di~m Clla timg phuong phap:
70
4.3.5.2 Thai gian th\fc hi~n t<;10lum TIN hoan chinh khi dUng cac phuong phap tim ki€m
(su d\mg phuong phap tim bao 16i Chi a D~ Trt va ch<;1ya ch€ dQ Release):
71
4.4 MQt s6 giai thu~t quan tr<;mg:
72
4.4.1 Giai thu~t d~t tam giac vao bang Bam
72
4.4.2 Giai thu~t ki~m tra mQt Face th6a di~u ki~n Delone
73
4.5 Thu~t toan t<;10lum tam giac d\fa theo y tllang Clla phuong phap tim bao 16i Melkman:
.............................................................................................................................................
75
4.5.1 Thu~t toan:
75
4.5.2 Vi d\l:
76
4.6 Thu~t toan t<;10lum tam giac d6i vm mQt vung co sful duemg bien:
82
4.6.1 Thu~t toan:
82
4.6.2 Vi d\l t<;10lum tam giac ban d~u til cac di~m thuQc duemg bien da dugc s5p theo chi~u
thu~ kim d6ng h6:
84
4.7 T<;1olucri TIN vcri duemg bien ben ngoai va cac vting 15m ben trong:
87
4.7.1 Phuong phap:
87
4.7.2 Vi d\l:
88
4.5 Chuong trinh minh hQa:
99
4.6 K€t Lu~:
'" 104
CHVONG 5 - cAc CONG NGHB vA NGON NGU
105
LAP TRiNH DVOC Sa DlJNG
105
5.1 H~ quan trt co sa dii li~u MySQL
l 05
5.2 Thu vi~n SQLAPI++
105
5.2.1 Gim thi~u
105
5.2.2 V u di~m
105
SQLAPI++ gQi tT\fcti€p cac ham API clla h~ quan trt co sa dii li~u dich
105
5.3 BCGControlBar
106
5.4 Thu vi~n d6 hQa 3D OPENGL
106
OPENGL LA CHUAN DO HOA DVOC CONG NHAN RONG RAJ
106
5.5 Ngon ngii su dl)ng
106
5.6 K€t lu~
106
CHVONG 6 - KET LuAN
107
6.1 Nhiing k€t qua d<;1t
dugc va nhiing dong gop mm
107
6.2 D~ xu~t cho huang ph
107
TAl LIBu THAM KHAo
108
DANH Ml}C KY HI~U VIET TAT
•
Ky hi~u
Di~n giai
GIS
Geographical Information Systems
GPS
Global Position System
TIN
Triangulated Irregular Network
DANH MVC
cAe HiNH vi:
Hinh 1: Use Case t5ng quat.
2
Hinh 2: UseCase chi ti~t.
3
Hinh 3:Cae 1<;>ai
ban d5
4
Hinh 4:Cae di;iedi€m ella ban d6
5
Hinh 5:Cae thong tin tren ban d6
5
,
.;;".;;"
b'
~
~
'b'
'nh
Hinh 6:BIeu dlen an do bang cae It tren may tl
.6
Hinh 7:du li~u Vector
6
Hinh 8:du li~u Raster
7
J...
*'"
.
Hinh 9:mOl
quan h~'" gma
eong
VI-'"
en Hyde va, h~0 Serpentme
.8
Hinh 1O:SVnguy hi€m ella nuae tri~u len
9
Hinh 11:Cae dieh Y\lkhc1ne~p
10
Hinh 12:Sv 0 nhi~m ti~ng 6n (; san bay
10
Hinh 13:MQt vi d\l don gian ella vi~e phan tieh m~ng la ehQn hai di€m (; tren m~g va sir
d\lng h~ th6ng thong tin dia ly d€ tinh duemg di ng~n nh~t giua chung
11
Hinh 14:Di~u khi€n xe
11
Hinh 15:Web Gis
12
Hinh 16:Mobile Gis
12
Hinh 17:Tu giae duqe t~o thanh ill tam giae 1 & 2
14
Hinh 18:Hi~u ehinh hai tam giae 1 & 2 thoa di~u ki~n Delone
15
Hinh 19:Thu?t toan t~o lum tam giae
16
Hinh 20:MQt s6 khai ni~m co ban trong mo hinh topo
17
Hinh 21 :G6e Anpha
21
Hinh 22:G6e Beta nhQn
22
Hinh 23 :G6e Beta til
23
Hinh 24:Phuong phap tim bao 16i vet e~ (ban dAu)
24
Hinh 25: Phuong phap tim bao 16i vet e~ (ban dAu)
24
Hinh 26: Phuong phap tim bao 16i vet e~ (ban dAu)
25
Hinh 27: Phuong phap tim bao 16i vet e~ (ban dAu)
26
Hinh 28: Phuong phap tim bao 16i vet e~ (ban dAu)
26
Hinh 29: Phuong phap tim bao 16i vet e~ (ban dAu)
27
Hinh 30: Phuong phap tim bao 16i vet e~ (ban dAu)
28
Hinh 31: Phuong phap tim bao 16i vet e~ (ban dAu)
29
Hinh 32: Phuong phap tim bao 16i vet e~ (ban dAu)
30
Hinh 33: Phuong phap tim bao 16i vet e~ (ban dAu)
31
Hinh 34: Phuong phap tim bao 16i vet e~ (ban dAu)
31
Hinh 35 :Cae vi tri ella cae di€m Start va End
33
Hinh 36:G6e Theta
34
Hinh 37: Phuong phap tim bao 16i vet e~ (cai ti~n)
35
Hinh 38: Phuong phap tim bao 16i vet e~ (eai ti~n)
35
Hinh 39: Phuong phap tim bao 16i vet e~ (em ti~n)
36
Hinh 40: Phuong phap tim bao 16i vet e~ (cai ti~n)
37
Hinh 41: Phuong phap tim bao 16i vet e~ (em ti~n)
37
Hinh 42: Phuong phap tim bao 16i vet e~ (cai ti~n)
38
Hinh 43: Phuong phap tim bao 16i vet e~ (cai ti~n)
39
A
'II
,
Hinh 44: Phuong phap tim bao 16i vet c~ (cai ti~n)
39
Hinh 45: Phuong phap tim bao 16i vet c~ (cai ti~n)
.40
Hinh 46: Phuong phap tim bao 16i vet c~ (cai ti~n)
.40
Hinh 47: Phuong phap tim bao 16i vet c~ (cai ti~n)
.41
Hinh 48: Phuong phap tim bao 16i chia d~ tri
.42
Hinh 49: Phuong phap tim bao 16i Melkman
.44
Hinh 50: Phuong phap tim bao 16i Melkman
.45
Hinh 51: Phuong phap tim bao 16i Melkman
46
Hinh 52: Phuong phap tim bao 16i Melkman
.47
Hinh 53: Phuong phap tim bao 16i Melkman
.48
Hinh 54: Phuong phap tim bao 16i Melkman
.49
Hinh 55: Phuong phap tim bao 16i Melkman
50
Hinh 56: Phuong phap tim bao 16i Melkman
51
Hinh 57:Lum Tin co ban ban d~u Clla mang di~m dii cho
53
Hinh 58:T~p di~m ban d~u(vm nhUng di~m d~ la nhUng di~m thuQc bao 16i)
54
Hinh 59:Minh h9a lum tin ban d~u a buac K = 2
55
Hinh 60:Minh h9a lum tin ban d~u a buac K = 3
56
Hinh 61 :Minh h9a lum tin ban d~u a buac K = 4
57
Hinh 62:Minh h9a lum tin ban d~u a buac K = 5
58
Hinh 63:Minh h9a lum tin sau khi qua buac 2
59
Hinh 64:Vi d\l minh h9a tim ki~m di~m vet c~
61
Hinh 65:Quan ly Lum Tin bfulg bang bam
62
Hinh 66:Vi d\l minh h9a tim ki~m di~m theo bang Bam
63
Hinh 67:Mo hinh cay RTree va d~g th~ hi~n theo khung chfr nh~t.
66
Hinh 68:Minh h9a vi~c them 1 di~m n~m ben trong Face vao Face(n la s6 c~ hi~n
co,NumberFace la s6 face hi~n co)
67
Hinh 69:Minh' h9a vi~c them 1 di~m n~ tren c~ clla Face rna c~ do khong co k~ vm
Face khac(idFace la chi s6 Face dang xet, n la s6 C<;1nh
hi~n co,NumberFace la s6 face hi~n
co)
68
Hinh 70:Minh h9a vi~c them 1 di~m n~ tren c~ clla Face rna c<;lnhdo co k~ vm Face
khac(idFace la chi s6 Face dang xet,idFaceNextTo la chi s6 Face k~ vm idFace qua c~
rna di~m n~ tren,n la s6 c<;lnhhi~n co,NumberFace la s6 face hi~n co)
68
Hinh 71 :Bi~u d6 th~ hi~n t6c dQ khi t<;10lum tam giac hoan chinh vm phuong phap tim
ki~m bfulg Bang Bam
72
Hinh 72:T<;10tam giac d~u tien
76
Hinh 73: Cac tam giac 1,2 duqc t<;10
khi xet di~m 3
77
Hinh 74:Tam giac 3 duqc t<;10
khi xet di~m 4
78
Hinh 75:Cac tam giac 4, 5 duqc t<;10
khi xet di~m 5
79
Hinh 76:Tam giac 6 duqc t<;10
khi xet di~m 6
80
Hinh 77:Tam giac 7 duqc t<;10
khi xet di~m 7
81
Hinh 78:Cac tam giac 8, 9 duqc t<;10
khi xet di~m 8
82
Hinh 79: Cac di~m thuQc dUOngbien dii duqc s~p theo chi~u thu~ kim d6ng h6
84
Hinh 80:Tam giac d~u tien duqc t<;10
khi xet di~m 0
85
Hinh 81 :Tam giac 1 duqc t<;10
khi xet di~m 1
85
Hinh 82:Tam giac 2 duqc t<;10
khi xet di~m 2
86
Hinh 83 :T<;1o
tam giac cu6i cling
87
Hinh 84: T<;1olum TIN vm dUOngbien ben ngoai va cac vling 15m ben trong:
88
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
Hinh
trong
85: T?o lum TIN vm dUOng bien ben ngOili va cac vimg lorn ben trong:
86: T?o lum TIN vm dUOng bien ben ngoai va cac vimg 10m ben trong:
87: T?o lum TIN vm dUOng bien ben ngoai va cac vimg lorn ben trong:
88:T?o lum TIN vm dUOng bien ben ngoai va cac vimg 10m ben trong:
89:T?o lum TIN vm dUOng bien ben ngoai va cac vimg lorn ben trong:
90:T?o lum TIN vm dUOng bien ben ngoai va cac vimg lorn ben trong:
91 :T?o lum TIN vm dUOng bien ben ngoai va cac vimg 10m ben trong:
92:T?o lum TIN vm dUOng bien ben ngoai va cac vimg 10m ben trong:
93:T?o lum TIN vm dUOng bien ben ngoai va cac vimg lorn ben trong:
94:T?o lum TIN vm duemg bien ben ngoai va cac vimg 10m ben trong:
95 :T?o lum TIN vm dUOng bien ben ngoai va cac vilng 10m ben trong:
96: Chuang trinh minh hQa lum TIN hoan chinh khi khong to mau cac Face
97: Chuang trinh minh hQa lum TIN hoan chinh khi khong to mau cac Face
98: Chuang trinh minh hQa lum TIN hoan chinh khi to mau cac Face
99: Chuang trinh minh hQa lum TIN vai cac dUOng bien co s~n
100 : Chuang trinh minh h(;mlum TIN vm cac dUOng bien co s~ va bao l5i ben
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
Trang 1
Chuang 1- Gi6i thieu
CHUONG 1 - GI61 THI~U
1.1 D6i tugng va ph~m vi nghien cme
Nghien Clm cac thu?t toan t6i uu t~o lucri tam giac (TIN).
1.2 Y nghia khoa hQCva th\fC tiSn:
Cac thu?t toan t~o lucri tam giac (TIN) la co s6, n@ntang dS giai quySt cac bai
toan nhu xay d\fllg ban d6 dia hinh; ch6ng lap thong tin; xay d\fllg vung d~m
cho cac d6i tugng, ... Tir do gop phAn giai quySt cac vfin d@quan trQng trong
cUQcs6ng nh~ giai toa, quy ~Oc;lchcac thanh ph6; quan ly, bao v~ va phat triSn
cac thanh pho, cac vung, mien thuQc cac quoc gia ... Vi V?y, vi~c nghien Clm
va t6i uu cac thu?t toan t~o lucri tam giac co y nghia khoa hQCva th\fC tiSn rfit
cao.
1.3 M\lc dich cua vi~c nghien Clm:
M\lc dich cua vi~c nghien Clm la t6i Uti thu?t toan t~o lucri tam giac va lrng
d\lng thu?t toan dS giai quySt cae bai toan:
- Xay d\fllg ban d6 dia hinh.
- Ch6ng lap thong tin.
- Xay d\fllg vung d~m cho cae d6i tugng.
".
Trang
Chuang 1- Gi6i thieu
Xay dung ban do dia hinh
/
/'
0/
A
Giai quyet cae bai toan chong lop
thong tin
User
Xay dung vung dem cho cae doi tuong
Hinh 1: UseCase t6ng quat.
2
Trang 3
Chuang 1- Gi&i thieu
.
0
o
«mcl~
Tao Juoitam giac voi
mot tap hop diem...
0
Xay dung ban do dia hinh
I
~
~
User
Xac dinh hoi cua hai
vung
«include» J'
/«include<>
~Xac
«include»
r
dinh giao cua
hai vung
Giai quyet cae bai toan
chong lop thong tin
«includ~
«include>
o
Tao Juoitam giac voi
mot vung co san
«include»
Xac dinh hoi nhung
khong Jay phan goo.
o
Xay dung vung dem cho cae
doi tuong
Hinh 2: UseCase chi tiSt.
1.4 Huang tiSp c~n:
Xay d\1l1gthu~t toan t~o lu6i tam giac b~ng cach ap d\mg cac c~u truc dfr li~u
sau:
- Mf> hinh Topology.
- Bang bam.
- RTree.
1.4 KSt lu~n:
Vi~c nghien Clm va t6i
hQCva tht,l'CtiSn r~t cao.
Uti
cac thu~t toan t~o lu6i tam giac co
y nghia khoa
Trang
Chuang 2-T6ng quan ve he th6ng thong tin dia Iy
CHUONG 2 - TONG QUAN vi: H~ THONG THONG TIN DJA
4
LY
2.1 Gi&i thi~u:
Vao th~p nien,30 va 40 clla thS ky 20, dS phan ti,ch dia Iy, con nguai sir ~\ln&
cac lo~i him do khac nhau. Til th~p nien 50, h~ thong dil co nhfrng phat trien de
co thS chuySn d6i nhfrng him d6 nay thilnh nhfrng dfr li~u duQ'c luu trfr trong
may tinh va sir d\lng cac dfr Ii~u nay dS phan tich, ghii quySt cac vftn
de.Nhfrng h~ th6ng do duQ'c gQi Ia h~ th6ng thong tin dia Iy (Geographical
Information Systems - GIS).
2.2 Ban d6:
2.2.1 Cac Io~i ban d6:
Lich SUClla h~ th6ng thong tin dia Iy b~t dAu til thS gi&i Clla han d6.MQt ban
d6 Ia mQt S\l thS hi~n mQt cach tf\lC quan, dan gian tdt ca mQi S\l v~t til thS
gi&i th\lc.Cac ban d6 co thS mo ta thS gi&i th\lc h~ng nhieu cach.
---- .•.
TopographIc
Contour
Choropleth
Real world
Hinh 3:Cac IQai ban d6
MQt ban d6 Topographic biSu diSn cac d~c diSm clla be m~t v~t Iy, vi d\l: cac
con duang, cac dong song, cac toa nha, ...
MQt ban d6 Contour biSu diSn nhfrng duang thAng n6i cac diSm 0 nhfrng vi tri
rna mQt thuQc tinh nao do co cung gia tri, vi d\l: dQ cao tren m\lc nu&c biSn,
cac duang dAng ap biSu diSn ap sudt khong khi.
MQt ban d6 Choropleth biSu diSn cac vung duQ'c mo ta boi mQt vai d~c diSm
chung ph6 biSn, vi d\l: cac Io~i cay tr6ng nong nghi~p.
Chuang 2-T6ng quan v~ he th3ng thong tin dia
Ii'
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2.2.2 Cae d~e di~m ella ban dB:
Di~m (Vd: mQt ddu th~p bi~u dien mQt nha tho).
Duang (Vd: mQt duang mau vang bieu dien mQt con duang).
Vung (Vd: mQt viIng mau xanh bieu dien mQt eai hB).
Van ban (Vd: ten ella mQt toa nha).
Hinh 4:Cae d~e di~m ella ban dB
2.2.3 Thong tin tren ban dB:
H~ th3ng thong tin dia ly phai co th~ lUll tni cae thong tin v~:
Hinh hQe: hinh dang va vi tri ella cae d~i tUQ11~.
Cae thuQe tinh: la cae thong tin mo ta ve cae doi tUQ11g,thuang duqe trinh bay
b~ng cae bi~u tUQ11gva loi ehil thieh 0 tren ban dB.Vd: mQt con duang duqe
rno ta boi ten, ehi~u dai, dQ rQng, ...
Combe Road
4.52 Km long
6.2 m wide
Tarmac surface
Hinh 5:Cae thong tin tren ban dB
Chuang 2-T6ng quan vS he thfmg thong tin dia Iy
Trang 6
2.3 Gi6i thi~u vS Raster va Vector:
2.3.1 Bi~u di~n ban dB bfulg cac bit tren may tinh:
Cac thong tin tren ban dB duQ'c luu trii, bi~u di~n tren may tinh du6i d~g cac
bit.
Hinh 6:Bi~u di~n bim dB b~ng cac bit tren may tinh
2.3.2 Dfr li~u Vector ( Vector Data):
Dinh nghia dfr li~u Vector:
Dfr li~u Vector Ia mQt day cac gia tri s6, thuang duQ'c bi~u di~n du6i d~g
diem, duang va vimg.
MQt diem duQ'cdinh nghia boi mQt c~p t<;>a
dQ x, y.
MQt duang thfulg duQ'c dinh nghia boi mQt day cac c~p tQa dQ x, y cua cac
diem t~o nen duang th~ng.
MQt vung duQ'c dinh nghia tuang tv nhu duang th~ng v6i diem dAu va diem
cu6i n6i I~i v6i nhau de t~o nen mQt hinh khep kin.
Hinh 7:dfr li~u Vector
Chuang 2-T6ng guan v~ he th6ng thong tin dia ly
Trang 7
Trong vi d\l a tren, ban dB mlY the hi~n mQt toa nha nhu mQt hinh chir nh~t
mau do, vi tri va hinh dang Clla toa nha duQ'c luu trir oou mQt day cac c~p tQa
dQ x, y clla 4 diem; de tai t:;10l:;1itoa nha nay trong h~ th6ng thong tin dia ly,
may tiOOdQc cac gia tri nay va ve mQt duang n6i cac diem l:;1iv&i OOau.
2.3.3 Dir li~u Raster(Raster Data):
DiOOnghia dir li~u Raster:
Dft li~u Raster OOumQt rna tr~n gBm OOi~u0, m6i 0 co mQt gia tri s6.
Dir li~u Raster duQ'c dung de luu trir cac hinh aOO,cac gia tri clla cac 0 lien
quan d~n mau clla cac diem t:;10nen hinh aOO.
Hinh 8:dir li~u Raster
Trong vi d\l tren, ban dB duQ'cchia thanh cac 0 r~t nho, cac gia tri s6 duQ'c luu
trir trong cac 0 la tr~ng, ho~c xanh, ho~c do. De tai t:;10l:;1ihinh aOO,may tiOO
dQc cac gia tri s6 trong cac 0 va ap d\lng chung d6i v&i cac diem tren man
hinh.
2.4 Topology:
DiOOnghia Topology:
Topology la t~t ca cac m6i quan h~ giira cac d6i tugng.
Vd: Cong vien Hyde a London co hB Serpentine nAm a ben trong.
Chuong 2-T6ng quan vS he th6ng thong tin dia
IV
Trang 8
n n
Topological map of Hyde park in London
Hinh 9:m6i quan h~ giiia cong vien Hyde va h6 Serpentine
2.5 Dii li~u dia 1y ( Geographical Data, Geospatia1 Data):
Dinh nghia dii li~u dia 1y:
Dii li~u dia 1y lUll trii cac thong tin vS vi tri, hinh dang va cac thuQc tinh clla
cac d6i tUQ11gtrong th8 gi6i th\lc.
2.6 Dinh nghia h~ th6ng thong tin dia 1y (Geographical Information SystemsGIS):
H~ th6ng thong tin dia 1y 1amQt h~ th6ng bao g6m con nguai, cac phdn mSm,
phdn ctmg may tinh va mQt co
dii 1i~u d~ lUll trii cac dii li~u dia 1y; co cac
chuc nang thu th~p, biSu diSn dii 1i~udia 1y mQt cach tIV'c quan tren may tinh
va co th~ c~p nh~t, phan tich, xu 1y, quim tri dii 1i~u dia 1y mQt cach hi~u qua,
gop phdn giai quy8t cac bai toan tmg d\lng lien quan t6i vi tri dia 1y tren bS
m~t trai dAt.
so
2.7 Thu th~p cac ngu6n dii 1i~uclla h~ th6ng thong tin dia 1y:
D~ thu th~p cac ngu6n dii 1i~uClla h~ th6ng thong tin dia 1y, nguai ta su d\lng
cac phuong phap khac nhau nhu do d~c tIV'Cti8p tren cac vung dAt cdn khao
sat, chuySn d6i tit ban d6 giAy sang hinh thuc lUll trii Clla ban d6 di~n tu. Co
hai phuong phap thuang duQ'c su d\lng do hi:
2.7.1 Phuong phap quet ( Scanning ):
Day 1a ky thu~t thong d\lng rna l~i it t6n kern, co th~ duQ'Cth\lc hi~n tren cac
may tinh ca nhan hay clla cong ty. May quet se lUll trii l~i cac hinh anh Clla
ban d6 giAy du6i hinh thuc s6 va hi~n thi chung tra l~i man hinh. Vi~c quet
hinh anh tit ban d6 giAy tuong d6i don gian va nhanh chong, tuy nhien
Chuong 2-T6ng guan v@he th6ng thong tin dia IV
Trang 9
phuong phap mlY khong thS cung c~p thuQc tiOOcua cac d6i tUQ11gt\1'OOien
nhu dia chi cua mQt toa nhil. Ou li~u co duqc tir OOUngphuong phap nay
thuOng duai d~ng Raster cho kich thuac r~t Ian.
2.7.2 Phuong phap s6 hoa (Oigitising):
Ky thu~t nay doi hoi phai cung c~p cac thiSt bi chuyen nganh. Ban dB nguBn
se duqc trai b@m~t ngang, mQt con tro se xac diOOtQa dQ cac diSm t~o nen
hinh d~g ban dB, sau qua trinh s6 hoa, thuQc tiOO cua cac d6i tUQ11gmai
duqc them vao. Phuong phap nay doi hoi nhi@uthai gian va nguBn du li~u co
duqc tir ky thu~t nay duai hinh thuc Vector.
2.7.3 Phuong phap vector hoa (Vectorisation ):
MQt vai h~ th6ng may tinh chuyen nghi~p co thS chuySn d6i du li~u Raster
sang d~ng du li~u Vector. Phuong phap na>,cho t6c dQ nhanh do tinh tv dQng
OOung I~i kern chinh xac hon so vai vi~c so hoa thu congo
Cac kY thu~t tren d@ud\1'avao nguBn du li~u ban dB gi~y co s~n. Tren th\1'ctS,
nguai ta con d\1'avao cac nganh IIOOV\1'Ckhac OOu:GPS, phan tich aOO... dS
thu th~p nguBn du li~u cho h~ th6ng thong tin dia Iy.
2.8 Cac lIng d1;1ngcua h~ th6ng thong tin dia Iy trong cUQcs6ng:
2.8.1 S\1'nguy hiSm cua nuac tri@ulen:
H~ th6ng thong tin dia ly co thS cho biSt cac thong tin quan trQng OOum\1'c
nuac hi~n thai la bao nhieu, nhUng vimg nao bi anh hu6ng khi nuac dang len,
•
Water level rls ng by 5 m
Impact on lIdjacenl urb
lIrelis
Hinh 10:S\1'nguy hiSm cua nuac tri@ulen
Chuong 2-Tang quan v~ he th6ng thong tin dia ly
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10
2.8.2 Cae dieh V\lkh~n e~p:
Bfutgeach su d\lng h~ th6ng thong tin dia ly, nguai ki~m soat cae phuong ti~n
cimh sat va e~p eUuco th~ ngay l~p tue gQidSn mQtnai 0 tren ban da ella khu
Y\lexung quanh nai xay ra sg vi~e.BAngeach theo d5i cae phuong ti~n theo
thai gian thge va su d\lng cae ehue nang tim duang ella h~ th6ng thong tin dia
ly, nguai ki~m soat co th~ nh~n ra phuong ti~n t6t nh~t d~ co m~t 0 nai xay ra
sg vi~e va chi ra duang di nhanh nh~t dSn nai do.
Hinh 11:Cae dieh V\lkh~ e~p
2.8.3 Sg 0 nhiSm tiSng an 0 san bay:
TiSng an ella may bay tlilisan bay lam anh huang dSn nhiing nguai s6ng 0
gAnsan bay. H~ th6ng thong tin dia ly co th~ eho biSt cae mue dQella tiSng an
ella may bay, nh,iin~kh~ vge bi anh huang boi tiSng an ella may bay d~ tir do
tim each hlilnehe tieng on ella may bay 0 mue eho phep.
Nolle level
100%
-75'1\
50%
25'1\
Public
complaints
>!5QIIOOO
Hinh 12:Sgo nhiSm tiSng an 0 san bay
---------------------------------Trang
Chuang 2-T6ng guan vS he th6ng thong tin dia IV
11
2.8.4 Phful tich m~ng:
Dinh nghia phan tich m~g:
Phful tich m~ng la cac xu ly toan hQc tren mQt m~g (V d: m~ng cac con
dUCmg) de co the tim duqc tfit ca cac con dUCmgtren m~g, tinh toan cac
khoang cach va thai gian.
Hinh 13:MQt vi d\l dan gian cua vi~c phan tich m~ng la chQn hai diem a tren
m~ng va su d\lng h~ th6ng thong tin dia ly de tinh dUCmgdi ngfuI nhfit giiia
chung.
A
Ie
•
•
•
B
o
A
•
e
•
B
.-
0'
DiSu khien xe:
Ap d\lng cac nguyen tAc cua phan tich m~g trong phan tich dUCmgdi, nguai
lai xe co duqc cac hu6ng d~n vS dUCmgdi, ting tr~g giao thong nhu th8 nao,
thai gian di la bao nhieu b~ng hinh ve tren ban de, va giQng noi.
Hinh 14:DiSu khien xe
Chuang 2-TAng quan
vB he th6ng
Trang 12
thong tin dia IV
2.8.5 Web Gis:
MQi nguai co thS su d\l11gcac dich Vl)cua h~ th6ng thong tin dia
Internet nhu xem cac hinh anh ban dB cua mQt nai nao do, ...
Internet GIS
I
Web Server
GIS lools
Dala
HTM
FAT CLIENT
Images
ly thong
qua
I
THIN CLIENT
Hinh 15:Web Gis
2.8.6 Mobile Gis:
H~ th6ng thong tin dia ly duQ'c (rng dl)ng tren di~n tho~i di dQng, nguai su
dl)ng di~n tho~i di dQng co thS bi~t duQ'c duang di d~n khach s~n, r~p chi~u
phim, tr~ xe bus, nha ga gAnnhdt, ...
Find Route•••
Hinh 16:Mobile Gis
Chuang 2-T6ng guan vS he th6ng thong tin dia ly
Trang 13
2.9 KSt lu~n:
H~ th6ng thong tin dja ly dfl giup giai quySt cae bai toan ilng d\mg lien quan
dSn vj tri dja ly tren bS ffi~t trai d~t ffiQteach hi~u qua va ngay cling phat trien,
holin thi~n, tra thanh S\Tl\Ta ch<;mcho S\Tthlinh cong cua ffiQinguai, ffiQi t6
chile, qu6c gia.
Chuang 3-T6ng guan vS thuat to{mtao lucri tam giac
Trang 14
CHUONG 3-TONG QUAN VE THU~T ToAN T~O LUm TAM GIAC
3.1 Mo til Thu~t toan chinh:
3.1.1 Dinh Nghia:
Vcri mQt t~p hQ'Pcac t9a dQ diSm bftt ky ban dfiu, ta xay d\ffig mQt lucri tam
giac th6a diSu ki~n clla Delone, ta g9i do la lucri tam giac Delone.
3.1.2 DiSu Ki~n:
MQt Lucri tam giac th6a diSu ki~n clla Delone khi va chi khi:
+Vcri m6i tam giac trong Lucri thi dUOng tron ngo~i tiSp clla tam giac do
khong chua bftt ky mQt diSm nao khac, ngo~i trir ba dinh clla tam giac dang
xet.
MQt C?P 2 tam giac kS nhau trong mQt Lucri tam giac th6a diSu ki~n Delone
nSu 2 tam giac nay dSu th6a diSu ki~n clla Delone.
DS dan giiin, thay vi phiii xet tUng tam giac trong Lucri theo dUOng tron ng9ai
tiSp Cllano xem co th6a diSu ki~n Delone hay khong ? Tu mQt tam giac ta xet
tUng C?P kS nhau cua chinh tam giac do vcri 3 tam giac Ian c~n(nSu co). Xem
C?P tam giac kS nhau do la mQt tu giac, va xet dQ dai 2 dUOng cheo cua tu
giac do (hai tam giac kS nhau qua mQt c~nh thi c~nh do la mQt trong 2 dUOng
cheo clla tu giac ).
DU
Hinh 17:Tu giac dugc t~o thanh til tam giac 1 & 2
Trang 15
Chuong 3-TAng quan v@thuat to{mtao lum tam giac
N@udUOng cheo la c~nh k@clla 2 tam giac (duOng cheo 1) co dQ dai nho hon
dUOng cheo con l~i (duOng cheo 2) thi C?P tam giac nay thoa di@u ki~n
Delone.(hinh 17)
NguQ'c l~i khi mQt C?P tam giac khong thoa di@u ki~n clla luai tam giac
Delone, ta co th~ xu 1;' b~ng cach d?t l~i dUOngcheo Clla C?Ptam giac do.
3.1.3 Vi d\l:
Gia su ta co tam giac 1 va cac tam giac k@vai no la 2-3-4. Ta xet til giac do
C?Ptam giac 1 & 2 t~o thanh, ta nh~n thfiy hai tam giac nay khong thoa di@u
ki~n Delone (do dUOng cheo la c~nh n6i gifra hai tam giac 1 & 2) co chi@udai
Ian hon dUOng cheo con l~i clla ill giac dang xet). D~ cho C?P tam giac nay
thoa di@uki~n Delone, ta phai sua l~i dUOng cheo clla til giac sao cho no co
chi@udai ng~n hon chi@udai Clla dUOng cheo hi~n t~i. (3.1.3.1)
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Khong Thoa
Hinh 18:Hi~u chinh hai tam giac 1 & 2 thoa di@uki~n Delone
3.1.4 Thu~t toan Delone:
Thu~t toan Delone duQ'cti@nhanh qua 3 buac sau:
Buac 1 : Tim bao 16i.
Buac 2 : T~o luac TIN ban d~u.
Buac 3 : T~o luai TIN hoan chinh.
Chuang 3-Tang quan vS thuat tmln tao lucri tam giac
J
I-f\
(} - __FindConvexAreaO: Tim baoloi.
:User
:'Int~ce
I: Open( FileName) I
~
Trang 16
:Triangulation
FrrstTnangulatlOnO: Tao tuOlTIN ban dau.
CompleteTriangulationO: Tao luoi TIN hoan chinh.
2: ReadFile~iteName, m_arrPbint)
3: FindConvexAreaO
I
I
I
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I
i" J:
DisJ1IayOn Scre~
I
Hinh 19:Thu?t toan t~o lucri tam giac
3.2 Cac cftu truc dfr li~u dugc su dVng:
3.2.1 Ma hinh topology:
NhUng khai ni~m da:dugc su dVng trong rna hinh tapa:
Start Node: Nut b~t d~u clla c~nh.
End Node: Nut kSt thuc Clla c~nh.
Right Edge: C~nh d~u tien g~p khi di chuySn ngugc chiSu kim d6ng h6 quanh
nut kSt thuc Clla c~nh hi~n t~i.
Left Edge: C~nh d~u tien g~p khi di chuySn ngugc chiSu kim d6ng h6 quanh
nut b~t d~u clla c~nh hi~n t~i.