project geo_xaml

I HC QUC GIA TP.HCM TRNG I HC BCH KHOA KHOA KHOA HC & K THUT MY TNH

Bo Co Thc Tp Cng Ngh Phn Mm

TM HIU GEO-XACML V GIS

GVHD: TRN TH QU NGUYT ---o0o--SVTH 1: L ON DUY KHNH 50800935 SVTH 2: TRN THCH LAM 50801039 SVTH 3: NGUYN HONG TH VINH 50802629

TP. H CH MINH, 01/2012

Mc lcChng 1: Gii thiu .................................................................................................................. 4 1.1. 1.2. S dng v trao i d liu a l: ................................................................................ 4 D liu a l v i tng khng gian a l: ............................................................... 6

Chng II: CC KIN THC NN TNG .................................................................................. 7 2.1. 2.2. 2.3. Ngn ng XML ............................................................................................................. 7 XML Schema. ............................................................................................................... 8 XPATH ......................................................................................................................... 8 nh ngha .................................................................................................................... 9 Cc thnh phn c bn trong ngn ng XACML .......................................................... 9 Qu trnh hot ng ca XACML ................................................................................ 10 Lc dng chy thng tin trong XACML: ............................................................... 11 Cc hm v kiu d liu trong XACML ....................................................................... 12 nh ngha GeoXACML .............................................................................................. 12 Cc Kiu Hnh Hc Trong Geo-XACML ...................................................................... 13 nh ngha cc Identifier ............................................................................................. 15 GeoXACML vi m hnh GeoRBAC. .......................................................................... 15 Gii hn quyn truy cp trong GeoXACML .......................................................... 16 c t cc permission khng gian, s dng GeoXACML ..................................... 20

Chng III: Ngn Ng XACML ................................................................................................... 9 3.1. 3.2. 3.3. 3.4. 3.5.

Chng IV: Ngn Ng Geo-XACML ......................................................................................... 12 4.1. 4.2. 4.3. 4.4.

4.4.1. 4.4.2.

Chng V: GIS ......................................................................................................................... 25 5.1. 5.2. 5.3. 5.4. Gii thiu : .................................................................................................................. 25 Cc b phn cu thnh GIS: .................................................................................. 26 Kh nng ng dng ca GIS ...................................................................................... 27 CC NHIM V CA GIS: ......................................................................................... 27 Nhp d liu: ....................................................................................................... 27 Thao tc d liu:.................................................................................................. 28 Qun L D liu: ................................................................................................. 28 Hi p v phn tch: ........................................................................................... 28 Hin th: ............................................................................................................... 29

5.4.1. 5.4.2. 5.4.3. 5.4.3. 5.4.4. 5.5. 5.6.

D Liu cho GIS ......................................................................................................... 29 Cc Cng ngh Lin Quan ......................................................................................... 29

Chng VI: Kt Lun ................................................................................................................ 31 Ti Liu Tham Kho:................................................................................................................. 31

Thc Tp Cng Ngh Phn Mm GEO-XACML

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Mc Lc Hnh:Hnh 1.1 ...................................................................................................................................... 4 Hnh 1.2 ...................................................................................................................................... 5 Hnh 3.1 ...................................................................................................................................... 9 Hnh 3.2 .................................................................................................................................... 11 Hnh 4.1 .................................................................................................................................... 13 Hnh 5.1 .................................................................................................................................... 26 Hnh 5.2 .................................................................................................................................... 27


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Chng 1: Gii thiu1.1. S dng v trao i d liu a l: Nhng loi d liu a l khc nhau c tp hp li nhm nhng mc ch khc nhau bi nhng nh cung cp dch v khc nhau. Mt yu cu ca vic kt hp v s dng d liu a l l tinh chnh d liu. Nhng kiu d liu v phin bn ph thuc vo c tnh d liu a l v ch nh s dng d liu . kt hp s dng, vic hin thc c iu khin bi mt tch hp d liu. Nh vy, tch hp d liu a l ( Geo-data integartion ) l th tc m n c th kt hp s dng bng cch mang nhng loi d liu khc nhau cho mt tin trnh.

Hnh 1.1 Tr tu d liu mang nhng d liu a l khc nhau vo trong mt h thng ch. Mt trong nhng phng php tip cn l n c lu tr, ni m d liu c duy tr v c cp nht. Tin trnh c th thng qua mt gin d liu o m i din cho mt gin trung gian. Mt gin ny cho php vic s dng d liu mt Thc Tp Cng Ngh Phn Mm GEO-XACML Page 4

cch thng dung, n nh l mt b chuyn i sang cu trc d liu thch hp h thng, trc khi truy nhp vo ni lu tr tht s. Nh vy lc n vi ngi dng u cui.

Hnh 1.2 : Phng php cung cp d liu a l trc tuyn khng ng nht v phn phi ra cc gin trung gian. y, mt adminisrtator c nhim v lm cho h thng hiu qu cho tr tu d liu bng cch cp nht vo mt ch lu d liu c gi l h thng ch (taget system), m m hnh ny gi l GIS. Mt trong nhng nhc im l h thng ch chng bao gi cp nht. Nhng ci nhc m ny li tr thnh u im ca phng php tip cn tr tu, ni m tin trnh ly d liu c cp nht. Mt cc hin thc ca phng php ny l d trn k thut Internet. Nhng nh cung cp dch v thit lp cng truy xut Internet, c gi l dch v web m nh cung cp nh ngha cch truy xut d liu. Nu mt dch v cung cp dch v h tr c bit nh x l tnh hung ging bn hoc phi hp chuyn i qua li nhng h thng tham kho, n c gi l mt Geo Web Service (GWS). gc mt gc nhn ca mt Geo Web Service c trng nh l mt n v tin trnh m n hot ng kt hp li nhng tin trnh hm v d liu a l cho mt lnh vc c th s dng. Thc Tp Cng Ngh Phn Mm GEO-XACML Page 5

Trong khi s dng tng tc d liu a l, c thu v t mt GWS, da trn khi nim c bn rng u ra ca dch v c th c iu khin bng nhng tham s u vo. iu ny cho php vic c th tch ring kiu nh dng ban u v m hnh nh n c s dng bi mt nh cung cp d liu v mt trung gian ha nh dng d liu, m n c cung cp bi GWS. Trong thi gian ngn, s c gng ny da trn nn trc tuyn v chuyn i d liu thi gan v khng lu tr d liu y v vnh vin. Mt gii hn ca cc kt qu lin kt tch hp d liu t mng cn thit. Qu trnh x l d liu c yu cu s lng ln d liu m n phi gi n dch v v nhn t dch v. V Vy, tc lin qua n kh nng ca mng li. Nhm s dng mt c s h tng trc tuyn ca mt dch v phn phi, m n cho php truy cp vo lin khi d liu a l, iu khin truy xut l bc buc. iu ny m bo cho nh cung cp c th bo v d liu theo ng mt cch mong mun. 1.2. D liu a l v i tng khng gian a l: Nh cp, d liu a l c thu thp v c duy tr cc dng d liu v v m hnh d liu khc nhau, theo mc ch ca qu trnh x l. Nhng loi ca d liu a l khng c ph hp c mt cu trc. V d, mt d liu hnh nh c khi lng cao nh c thu thp t mt v tinh thi tit da trn d liu a l. N khng phi c nh trc c trong tt c m hnh d liu. Nhng nhng hin tng khc c th c quan st v o thng qua thit b chuyn dng ( trc a (geodetic)), c m hnh qu trong m hnh hng i tng. V d, mt con ng c th c th hin trong mt m hnh d liu hng i tng. Theo chun ISO 19107, mt thng tin i tng trong bi cnh ny l mt s tru tng ca mt hin tng th gii thc. Cc i tng thng tin c gi l mt i tng khng gian a l hay i tng thng tin khng gian nu n kt hp mt v tr tng i vi b mt tri t. Theo m hnh hng i tng, mt i tng l mt th hin ca lp m n xc nh thuc tnh ca i tng. i din ca thng tin ny c li th l tham kho ti mnh thng tin c bn (the raster-based information) m mt i tng c th c xc nh duy nht v t ng x l. Tin trnh x l mnh d liu ch yu l qu trnh th cng. Thc Tp Cng Ngh Phn Mm GEO-XACML Page 6

Cch tip cn hng i tng c mt u im ln khc rng n cho php c th kt hp thng tin ph thuc vo nhau, nh ngha cc hot ng cho tin trnh x l v m hnh quan h gia cc i tng. iu ny mng mt li th tri vi trng hp trc, mt ci my c th phn bit c gia cc i tng ca mt trong hai lp v con ngi, khng cn nhn qua lp ha bn ngoi. Hn na, Hng tip cn hng i tng cho php a phin bn ca mt lp ( i tng ) mt kiu xc nh ring bit x l da vo, thm ch gi tr thuc tnh n c th thay i. Da trn nhn dng duy nht, n c th th hin mi quan h gia cc i tng. Cc loi quan h ny c th l khng gian hoc phi khng gian. Mt v d cho quan h phi khng gian l mt quan h s hu; mt v d cho quan h khng gian l quan h lin k, cn c trn mt i tng hnh hc ca mt i tng thng tin khng gian. M hnh hng i tng ca cc i tng khng gian a l c yu cu th hin c nhng c im khng gian a l. V tr v hnh dng ca mt i tng khng gian a l c m t bng hnh hc.

Chng II: CC KIN THC NN TNG2.1. Ngn ng XML

XML ( eXtensible Markup Language) l mt ngn ng c thit k m t v mang thng tin, cc thng tin c cu trc, hay chnh xc hn l mang d liu. Hin nay n l cng c ph bin nht truyn thng tin gia tt c cc mi trng x l thng tin, gia cc my tnh, gia cc chng trnh vi nhau v vi ngi dng. V tnh n gin v c kh nng m rng nn n c s dng ngy cng rng ri. Trong nghin cu ny ta s thy XACML v GeoXACML thc cht cng l XML. V cc Document ca chng ta cng u c encode bng XML. XML cng s dng cc tag ng v m nh du, cc tag ny khng c nh ngha trc. Tng quan : c th hnh dung XML n gin nht, nhanh nht vi nhng ai quen thuc vi HTML, ta c ngh n ging HTML nhng cht ch hn v khng cho php ngoi l. N yu cu tnh chnh xc v khng c li m ha, khng ging nh HTML cho php li nhng ni trong ti liu v cc chng trnh x l c th b qua, v x l phn k tip. Vi XML nu c Thc Tp Cng Ngh Phn Mm GEO-XACML Page 7

li n s dng . Cc chng trnh x l XML thc thi nhanh v khng cng knh nh i vi HTML. XML khc vi HTML nhng im : XML chnh xc, XML dng mang thng tin v tp trung vo vic din t thng tin l g trong khi HTML tp trung vo vic din t thng tin c trnh by nh th no .

V cu trc v c php ca XML, chng ti khng cp chi tit v khng thuc phm vi ca nghin cu chnh . Ngun tham kho chi tit v chnh xc nht xin tham kho http://www.w3.org/standards/xml v http://www.w3schools.com/xml/default.asp . 2.2. XML Schema.

Khi nim : XML Schema nh ngha cu trc ca 1 XML Document. N ra i sau DTD ( Document Type Definition ), nhng tr nn mnh hn DTD trong vic nh cu trc cho XML Document nh mt s kh nng nh : h tr nhiu kiu d liu hn, phong ph hn v c vit bng c php XML ( n gin v ngi ta khng mc cng hc thm 1 loi ngn ng mi ) kh nng m rng v h tr namespace. XML Schema m t : + Cc element xut hin trong 1 XML Document + Cc attribute trong 1 document + Cc element no l con ca element no + S element con ca 1 element no . + Trt t ca cc element con. + Liu 1 element c th rng hay khng hay l phi chng text, hay l phi cha th g bn trong. + Data type cho cc element v cc attribute. + Default value v fixed value cho cc element v attribute. Cc tham kho tham kho cc trang hng dn XML ni trn. 2.3. XPATH

Khi nim XPath (vit tt cho XML Path) theo ng tn gi ca n, l nhng biu thc ng dn n cc thnh phn trong cc XML Documents. Nhng biu thc ny Thc Tp Cng Ngh Phn Mm GEO-XACML Page 8

trong tng t nh nhng biu thc ng dn dng trong cc h thng file bnh thng ca my tnh hin nay, c bit ging trong cc h Unix v Unix-base. XPath l thnh phn quan trng trong chun XSLT ca W3C v trong XQuery. Trong biu thc ca XPath dng cc khi nim Node, Operator, Axes, v Function

Chng III: Ngn Ng XACML3.1. nh ngha L vit tt ca eXtensible Access Control Markup Language. L ngn ng c t chnh sch kim sot truy cp kiu khai bo da trn ngn ng XML. V y cng l mt hnh thc x l m t lm th no gii thch c cc chnh sch . 3.2. Phin bn mi nht c t chc OASIS ph chun vo thng 2/2005. Cc thnh phn c bn trong ngn ng XACML

Hnh 3.1: cc thnh phn XACML v mi lin h gia chng Thc Tp Cng Ngh Phn Mm GEO-XACML Page 9

XACML c ba thnh phn c bn l , v . Cng vi 4 hot ng h tr l PAP, PDP, PEP v PIP c th: PAP - Policy Administration Point: l ni qun l cc chnh sch. PDP- Policy Decision Point: l ni nh gi v a cc quyt nh cp quyn. PEP- Policy Enforcement Point: l ni chn yu cu ca ngi dng truy cp vo ti nguyn v thi hnh quyt nh ca PDP. PIP- Policy Information Point: L ni cung cp thng tin h tr cho PDP. Ngn ng XACML hot ng da trn 3 thnh phn l Request, Policy v Response. Request; l yu cu truy cp c gi t ngi dng. Policy: l tp tin chnh sch h thng dng kim cho quyt nh y quyn. Response: l kt qu c tr v sau khi kim tra gia request v policy. Thnh phn Request: Mt Request l mt yu cu truy cp c gi i t ngi dng. Trong bao gm cc thuc tnh: Subject, Resoure, Action v Environment. Thnh phn Policy: Policy trong XACML c cu trc thnh 3 cp: PolicySet, Policy v Rule. Tt c chng u cha thnh phn Target. Thnh phn PolicySet c th cha cc PolicySet khc hay cc Policy. Cn Policy th c th cha cc Rule. Mi Policy c nh ngha vi mt tp cc Rul. Mi Rule v Request u gm cc thnh phn Subjecs, Resoures v Actions. Thnh phn Response: Response l kt qu c tr v sau khi PDP so snh Request vi cc Policy tng ng. Mt Response bao gm 3 thnh phn l Decision, Status v Obligations. 3.3. Qu trnh hot ng ca XACML


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Hnh 3.2: kin trc hot ng ca XACML C 4 b phn h tr hot ng cho XACML l PIP, PEP, PDP, PAP cng 3 thnh phn chnh l Request, Policy, Response. Da vo ta c th t hot ng trong XACML to ra c 1 quyt nh cp quyn khi c 1 ngi mun to ra mt request yu cu truy cp vo d liu ca h thng: 1)Request truy cp c chn lc bi Policy Enforcement Point (PEP) 2)PEP ny s hnh thnh 1 request theo chun XACML v s dng cc t kha trong truy cp v phn b sung them cn thit t Policy Information Point ( PIP) 3)XACML request sau s c a n Policy Decision Point (PDP) 4)PDP s ly cc policy cp quyn ghp vo request . 5) PDP s ly cc thuc tnh cn thit ra so snh gia request vi policies. 6)Da vo kt qu so snh, quyt nh s c tr v nh mt XACML response n PEP. 7)PEP s quyt nh t chi hay cho php truy xut . 3.4. Lc dng chy thng tin trong XACML:


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Da vo qu trnh hot ng trong ngn ng XACML, ta c lc dng chy thng tin trong XACML. Lc dng chy thng tin nh ngha kin trc ca mt h thng theo kiu module. Thm vo , n n ngha thm s trao i thng ip gia cc thnh phn cng nh cu trc ca cc thng ip PAP: l thnh phn cho php mt hay nhiu khi qun tr policy duy tr quyn truy cp cho mt tp cc policys. Thm vo PAP c th cung cp mt interface ring cho cc policy yu cu. PDP: l thnh phn c th xut ra mt quyt nh y quyn da vo mt request nhn t mt hay nhiu PEP. Mt PDP c th yu cu policys yu cu t PAP v s dng kho policy trong mt tp tin hay mt kho d liu. PEP: c th m t nh mt cng tc hai chiu m c th p ng cc dch v n tng request ca khch hng tng ng hay tr li vi mt thng bo li y . 3.5. Cc hm v kiu d liu trong XACML Cc kiu d liu xut pht t XML Schema, XQuery v c bit ch c XACML. Ring cc loi hm, ta thy c cc tp hm rt nhiu lnh vc. Trong ta thy c c hm thi gian. C ngha l XACML h tr rng buc v mt thi gian trong qu trnh truy xut d liu. Cc kiu d liu : From XML Schema : String, Boolean, Integer, double, time, date, anyURI, HexBinary.. From Xquery : dayTimeDuration, yearMonthDuration.. Unique to XACML : rfc822Name. x500Name.. Cc loi hm : Equality predicates, Arithmetic functions, String conversion functions, Numeric type conversion functions, Logical functions, Arithmetic comparison functions, Date & time arithmetic, non-numeric. Special math functions, XPath-based functions, Extension functions and primitive types.

Chng IV: Ngn Ng Geo-XACML4.1. nh ngha GeoXACML Page 12


- Vit tt ca Geospatial Extensible Access Control Markup Language. c gii thiu bi Open Geospatial Consorithm (OGC) nh l 1 phn m rng ca XACML, cung cp c t thc thi da vo d liu thong tin a l. Tr thnh 1 chun ca OGC vo 2/2008. Phn m rng cho XACML c them cc thuc tnh hnh hc v cc hm v khng gian. Cc thuc c nh ngha trong m hnh hnh hc ca GeoXACML : Point, LineString, Polygon v MultiPoint, MultiLineString, MultiPolygon tng ng vi tp hp ca 3 thuc tnh u Cc hm khng gian c chia thnh 5 loi : Topological, Geometric, Bag, Conversion v Set. nh ngha cc thnh phn trong Geo-XACML: XACML nh nghi nhng thnh phn c th m rng c. l DataTyp, FunctionID v AttributedId. Nh vic m rng thm thuc tnh khng gian cho cc thnh phn ny m GeoXACML c ra i nh nga kiu d liu mi: mt thnh phn c kiu l , c th c mt thuc tnh l datatype c kiu anyURI, vi iu kin bt buc phi c. S ln xut hin c th l 0 hay nhiu hn.

Hnh 4.1 : Mt kin trc GeoXACML n gin 4.2. Cc Kiu Hnh Hc Trong Geo-XACML


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So vi XACML, GeoXACML m rng them cc kiu d liu hnh hc cng vi cc hm khng gian Gi tr cho 1 kiu d liu hnh hc vi URN tng ng phi c trnh by qua 1 trong s cc kiu c bn sau : . Point : l i tng hnh hc 0 chiu v i din cho 1 v tr n l trong ta khng gian. 1 point cho 1 gi tr ta x v 1 gi tr ta y . Nu trong khng gian c th c thm z v m. . LineString : l 1 ng cong vi php ni suy tuyn tnh gia cc Points. Mi cp im lin tip to thnh 1 on thng. T kiu ny ta c kiu c bin l ng cong khp kn LinearRing. .Polygon ( hay cn gi l Surface) l 1 b mt c to ra bi mt vng bin bn ngoi v 0 hay nhiu hn cc bin gii bn trong. Mi bin gii bn trong l mt l trng trong Polygon. . Box: l vng dng hnh ch nht (envelop) c 2 ta : 1 im gc di ca hnh v 1 im gc trn ca hnh ch nht . .MultiPoint: l 1 tp hp hnh hc 0-chiu thnh phn con l cc Points. .MultiLineString: l 1 tp hp gm nhiu ng cong l cc LineString. .MultiPolygon: l 1 a din vi cc thnh phn con l Polygons. Cc hm khng gian trong GeoXACML: Cc hm Topological(a hnh hc) VD:Contain(g1:Geometry, g2:Geometry):Boolean. Crosses(g1:Geometry, g2:Geometry):Boolean. Disjoin, Equals, Intersets, Overlaps, Touches, Within. Cc hm Geometric(hnh hc) VD: Buffer(g:Geometry,d:Double):Bag; Boundary(g:Geometry):Geometry; Convexhull(g:Geometry):Geometry; Centroid(g:Geometry):Geometry; Difference(g1:Geometry, g2:Geometry):bag; Sym Difference(g1:Geometry, g2:Geometry):bag; Intersection(g1:Geometry, g2:):bag; Union Difference(g1:Geometry, g2:Geometry):bag; Thc Tp Cng Ngh Phn Mm GEO-XACML Page 14

+ nh ngha cc hm hnh hc v hng: Area (g:geometry) :double Distance (g1:Geometry , g2:Geometry):double IsWithinDistance (g:Geometry):Boolean Length (g: Geometry):Double .nh ngha cc hm kim tra nhng tnh cht chuyn bit: IsSimple(G:Geometry):Boolean IsClose (g:Geometry):Boolean IsValid (g:Geometry):Boolean + nh ngha cc hm Bag (ti) GeometryOneAndOnly(b:Bag) :Geometry GeometryBagSize (b:bag):Integer GeometryIsIn(g:Geometry, b:Bag):Boolean GeometryBag(g*:Geometry):Bag +nh ngha cc hm Set (tp hp) GeometryBagIntersection(b1:Bag, b2:Bag):Boolean GeometryBagAtLeastOneMember(b1:Bag, b2:Bag): Boolean GeometryBagUnion(b1: Bag, b2:Bag):Bag GeometryBagSubset(b1:Bag, b2:Bag):Boolean GeometrySetEqual(b1:Bag, b2:Bag):Boolean 4.3. nh ngha cc Identifier

Trong qu trnh hin thc GeoXACML ta phi s dng cc thuc tnh cng vi cc indentifiers ca n. Ct th hai ca cc bng bn di l tn ca cc hm tng ng nh lit k trc. 4.4. GeoXACML vi m hnh GeoRBAC.

M hnh GeoRBAC l mt m hnh gii hn quyn truy xut d liu a l gn vi v tr ngi dng. Minh ha c th nh ngi dng A s c truy xut d liu bn TPHCM nu ngi ny trn a bn TPHCM vo ng lc pht ra yu cu truy xut Thc Tp Cng Ngh Phn Mm GEO-XACML Page 15

d liu. Nu ngi ny i khi TPHCM lc pht ra yu cu th s khng c chp nhn cho truy xut d liu bn TPHCM na. V v tr ca ngi dng lc pht ra yu cu truy xut s c tnh ton da trn cc thng s nh phn GeoRBAC. Nhng m hnh GeoRBAC trong ngn ng GeoXACML khng cn l gii hn quyn truy xut d liu ng vi v tr ca ngi dng na, m by gi l gii hn quyn truy xut d liu ng vi v tr ca d liu. C ngha l vi v d trn, ngi dng A s c gn sn cc v tr hay vng khng gian c php truy xut, gi d nh TPHCM. A bt k ni u khi yu cu 1 v tr hay 1 vng khng gian no , nu v tr hay vng ny m nm trong vng a l cho php tng ng l TPHCM th kt qu tr v s l cho php nhng nu vng mong mun nm ngoi vng cho php nh Long An th s t chi tr v kt qu cho ngi dng A. 4.4.1. Tng quan: Nh phn bn trn ta phn tch r v cch hn ch truy xut d liu a l khng gian m ng vi v tr ca d liu. Mt ngi dng s c gn vi cc vng khng gian cho php truy xut. V ty thuc vo vng h mun truy xut so snh vi vng ban u, kt qu s l cho php hoc t chi. thc hin c cng vic ly yu cu truy xut ca ngi dng, sau so snh n vi vng khng gian truy xut tng ng vi ngi , ta dng n cc Web Services. Ph bin nht l Wep Map Service(WMS) v Web Feature Service(WFS). Gii thiu hot ng hn ch quyn trn cc tp tin policy Gii hn quyn truy cp trong GeoXACML

4.4.1.1.

M hnh bn di ch ra qu trnh hot ng ca mt h thng s dng cc policy GeoXACML. Cc policy ny c lu tr GeoXACML Policy Repository, thuc tng gia ca chu trnh hot ng. WMS ng vai tr l cng c h tr hot ng trong sut qu trnh thc thi mt yu cu ca ngi dng, t lc gi n lc tr v kt qu. C th, khi ngi dng Alice tng tc vi mt WMS Client gi Request xung PEP, lc PEP, PDP s thc thi qu trnh xc thc yu cu ca Alice vi cc tp tin policy ca h thng. Kt qu a v PEP s gi tip n WMS Service thao tc ly ra d liu c lu tr Geodata Repository. 4.4.1.2. Cc yu cu v iu khin truy cp dng trong WMS v WFS Page 16


Cc yu cu v iu khin truy cp trong WMS v WFS l: + Khng th gii hn quyn truy cp vo ton b service khi cho php ngi dng xc thc c quyn truy cp vo tt c cc d liu a l c cung cp. + Class based restrictions: ta c th gii hn quyn truy cp n tt c cc i tng resource ca mt lp chung. i tng WMS(Web Map Service), yu cu ny ni n kh nng gii hn quyn truy cp bn vo mi lp hay mt tp cc lp ring r. i tng WFS(Web Feature Service), yu cu ny ni n kh nng gii hn quyn truy cp cho mt kiu feature hay mt tp cc kiu features. + Object based restrictions: ta c th gii hn quyn truy cp ca ngi dng n cc objects ring r ca mt lp. Khng c s tng ng cho cch truy cp WMS. i vi WFS, yu cu ny ni n kh nng gii hn quyn truy cp cho cc features ring r(mt feature hay mt tp cc features). + Spatial restrictions: ta c th gii hn quyn truy cp ca ngi dng da vo cc resources hnh hc nu c mt mi lin h khng gian n mt dng hnh hc tn ti cho trc. i vi WMS, yu cu ny ni n kh nng mt bn c th c yu cu, nu khu vc mong mun nm trong vng gii hn cho php. i vi WFS, yu cu ny ni n kh nng cc features c th c truy cp, nu n bn trong1 vng cho trc hay chm vo ng cho trc. + Ta c th khai bo khng nh hay ph nh din t s gii hn quyn, nh l ngi dng A c th c tt c cc features ca kiu Building, nhng khng phi vi c tn The White House. + Ta c th kt hp permission v class-based, object-based v special. Nh v d, ngi dng A c th c tt c cc features vi kiu building bn trong khu vc Washington D.C, nhng khng phi vi building c tn The White House. Cc minh ha v gii hn quyn truy cp: Thc Tp Cng Ngh Phn Mm GEO-XACML Page 17

Phn ny cung cp gii hn quyn truy cp dng vn bn c th. Mi v d ny khng bao ph v mt chc nng ca Geo-XACML. t bit l khng c s dng phn kt hp ca cc cho php v class-based, object-based, spatial. Cc v d cho WMS im chung cho tt c cc v d, vic m t cc gii hn quyn cho mt truy cp bn WMS l cu trc ca ni dung resource c m t bi mt tp cc feature GML. S t v thc thi ca cc gii hn quyn truy cp cho phn feature-info l ging vi WFS cho php ton read. + Class-based restriction Pla: Alice c th map lp COASTL. Plb: Bob c th map tt c cc lp, ngoi tr lp COASTL. Plc: Tt c cc yu cu khc b t chi. + Object based restrictions Khng c v d c xc nh cho object-based restriction, bi v n tng t vi cc v d ca WFS, s dng php ton read. + Spatial restriction P2a: Alice c th map lp COASTL trong vng 3 0.6 1.6 5.1 5.0 2.3 0, c din t trong h thng khng gian tham chiu foo. P2b: Tt c cc yu cu khc u b t chi. Cc v d cho WFS im chung cho tt c cc v d, vic m t cc s gii hn quyn cho mt truy cp WFS l cu trc ca ni dung resource c m t bng mt tp cc feature GML(nh v d City Model.xsd). + Class-based restrictions P3a: Alice c th read tt c cc feature ca kiu building. P3b: Bob c th write tt c cc features ca kiu Intersertion v c th read tt c cc feature ca kiu Building. P3c: Tt c cc yu cu khc u b t chi. + Object-based restrictions P4a: Alice c th read feature building, khi n c xc thc bi fid The While House. P4b: Tt c cc yu cu khc u b t chi. Thc Tp Cng Ngh Phn Mm GEO-XACML Page 18

+ Spacial restrictions P5a: Alice c th read cc feature ca kiu building, nt n trong vng 3 0.6 1.6 5.1 5.0 2.3 0, nh c din t trong h thng khng gian tham chiu foo. P5b: tt c cc yu khc u b t chi. 4.4.1.3. Cc Identifiers h thng tham chiu ta CRS Mc d dng nh hnh ca cc geometries c s khc bit v CRS(Coordinate Reference System), nhng chng phi cng s dng chung mt h tham chiu ta . a ra mt quyt nh cp quyn v khng gian th c hai geometries phi chung CRS vi nhau. C bn ta c hai la chn l: + CRS c chn vo AuthorrizationDecisionRequest nh l mt thnh phn ca Attribute Value. iu ny yu cu cc dch v thc thi phi cha cc thng tin . Nu thng tin CRS c sn nh mt Attribute Value, mt cuc kim tra tng th s c tin hnh trn ton b ni dung Resource. + CRS c ly t geometry s c kim tra. iu ny c u im l s tng ng CRS ca geometry c kim tra ngay lc trc khi cc mi lin h khng gian c nh gi. C 2 CRS thng dng, l CRS foo v CRS EPSG:4326. + M ha s dng CRS gi foo c c t trong Cartesian Coordinate System(h ta Cc). Thng tin c m t nh h ta Cc m ta c hc v hay dng trong ton hc. Nh v d bn di: SimpleSurface = {foo, 0 0, 3 0, 3 4, 0 4, 0 0} ComplexSurface = {{foo, 0 0, 3 0, 3 4, 0 4, 0 0}, {foo, 1 1, 2 1, 2 3, 1 3, 1 1}} + EPSG l vit tt ca EuroPean Petroleum Survey Group, t chc bao gm cc chuyn gia iu tra, o c v v biu t cc cng ty du la trn chu u v c hot ng trn ton th gii. Mi nm hp li 2 ln tho lun iu tra v nh v cc ti trong lnh vc kinh doanh ca ngnh cng nghip du la, ni c li ch chung ca h. Cc nhm lm vic o c ca EPSG duy tr v cung cp danh sch cc CRS r rng. Mt CRS quan trng l World Geodetic Standard 1984 (WGS84) v c s dng rng ri trong Global Positioning System(GPS). Cc chui nh dng EPSG cho WGS84 l EPSG:4326. Thc Tp Cng Ngh Phn Mm GEO-XACML Page 19

4.4.1.4.

Cc Identifiers Service/Operation

Cc gii hn quyn truy cp c gn vi d liu a l, mc d d liu l c th c truy cp thng qua cc thao tc dch v. Minh ha,WFS1 v WFS2 cung cp truy cp n mt vng d liu a l chung, nhng WSF1 tr v d liu a l mt cu trc khc vi WFS2. iu ny ngha l mc d permision ca hai dch v l nh nhau, nhng cc s suy din Xpath so trng vi cc resources l khng ging nhau gia WFS1 v WFS2. iu ny i hi ta phi gn kt mt permision vi mt Service/Opertion no , c c ng cu trc ca cc resources cng nh l ni dung ca thnh phn . 4.4.1.5. Ngn ng Geography Makeup Language(GML)

GML l mt chun quc t ca OGC( Open GIS Consortium, Inc. : mt t chc thng mi quc t phi li nhun dn dt cng vic pht trin cc tiu chun cho kh nng tnh ton x l d liu a l). GML l mt m ha XML cho vic vn chuyn v lu tr cc thng tin a l, bao gm c tnh cht spatial v non-spacial ca cc features a l. y ta s dng phin bn GML 2.1.2, gn vi php ni suy tuyn tnh vi cc dng hnh hc n gin. Tuy phin bn GML 3.0 ra i, nhng n c xem nh khng c lin quan. GML cng cung cp c t XML cho cc dng hnh hc m c nh ngha trong lc hnh hc. Cc lp c s tru tng ca cc lc hnh hc l gml:_Geometry. N c cc thuc tnh ty chn l gid lu tr identifier ring cho dng hnh hc v thuc tnh srsName lu tr identifier cho CRS c dng. 4.4.2. c t cc permission khng gian, s dng GeoXACML

c t c cc permision khng gian cho ngi dng, ta cn phi c cc vng khng gian c php truy cp cng nh kiu vng khng gian m ngi dng Thc Tp Cng Ngh Phn Mm GEO-XACML Page 20

khi mun truy xut n. T , da vo tnh cht ca hm kt hp 2 thuc tnh , cc permision tr v l cho php hay t chi. 4.4.2.1. c t cc vng khng gian gii hn truy cp trong GML

GML 2.1.2 nh ngha tp cc lp hnh hc c bn, v c s dng y bao gm: Point, LineString, LineaRing (dng c bit ca LineString), Polygon (cn gi l Surface) v kiu Box. Nh vy, trong GeoXACML, c 5 kiu vng khng gian a l 2 chiu m c th c gn vi quyn truy cp ca mi ngi dng l: Point, LineString, LinearRing, Polygon v Box. + Gml:Point M ha GML cho gml:Point c trnh by lc bn di Point vi kiu PointType, c th c m ha bng thnh phn gml:coord hay gml:coordinates. Thnh phn coord i theo nhm cc gi tr(X, Y, Z) trong Y v Z l khng bt buc. Tng t thnh phn coordinates c cc gi tr c nh ngha theo kiu chui String mang cc gi tr X,Y v Z. Point = {CRS, Coord} Coord = X Y 1 2 3 4 5 6 7 8 9 10 11 12 A Point is dened by a single coordinate tuple.

13 Lc : M ha GML cho dng hn hc Point. + Gml:LineString M ha GML cho gml:LineString c trnh by lc bn di. Thc Tp Cng Ngh Phn Mm GEO-XACML Page 21

Dy 2 hay nhiu hn thnh phn coord cha cc points ca chui cc on thng. Dng hnh hc Line c th c m ha di dng LineString vi 2 thnh phn coord. Line = {CRS, Coord1, Coord2} LineString = {CRS, Coord1, Coordi, Coordn} |Coord1 Coordn 1

between them. 5 6 7 8 9 10 11 12

13 Lc : M ha GML cho dng hnh hc LineString + Gml:LinearRing M ha cho thnh phn gml:LinearRing c trn by lc bn di. Dy 4 hay nhiu hn thnh phn coord cha cc points ca chui cc on thng. iu quan trng l LinearRing l dng hnh hc khp kn. V th, im u v im cui phi trng nhau. Nhng iu ny khng c thc hin bi GML. LinearRing = {CRS, Coord1, Coord2, Coordi, Coord1} 1

between them. Thc Tp Cng Ngh Phn Mm GEO-XACML Page 22

5 6 7 8 9 10 11 12

13 Lc : m ha GML cho dng hnh hc LinearRing + Gml:Polygon Trong GML, thnh phn Surface khng c m ha trc tip m phi thng qua lp Polygon nh lc bn di. Thnh phn gml:outerBoundaryIs cha mt dng hnh gml:LinearRing c t vng bin bn ngoi ca gml:Polygon . Cn cc vng bin bn trong khng bt buc c lu dy thnh phn gml:innerBoundaryIs. Mi thnh phn ny cng l mt gml:LinearRing. Surface = {LinearRing1, LinearRingi} 1

between them. 5 6 7 8 9 10 11 12

13 Thc Tp Cng Ngh Phn Mm GEO-XACML Page 23

+ Gml:Box Trong GML, Box l mt dng hnh hc ch nht(envelop), bao gm chnh xc hai ta : 1 l ta im gc di lowerCorner, 1 l ta im gc trn upperCorner. Hai ta ny to nn hnh ch nht. 4.4.2.2. c t cc permission khng gian vi thnh phn

+ nh ngha thnh phn Thnh phn Condition vi kiu xacml:ApplyType cho php khai bo cc iu kin phc tp m iu khin u ra ca mt Rule. Lc di y trnh by cu trc lc XML cho thnh phn Conditionn. y l phn m t tng qut m ta cn quan tm. 1 2 3 4 5 6 7 8 9 10 11 12 13 Lc : nh ngha XMLSchema cho thnh phn Khng ging vi cc thn phn PolicySet, Policy v Rule, thnh phn Condition cung cp nh ngha cc rng buc trn tt c cc attributes bi cc thnh phn SubjectAttributeDesignator, ResourceAttributeDesignator, ActionAttributeDesignator hay EnvironmentAttributeDesignator. Thm vo , cc iu kin phc tp hn c th c nh ngha bng cch s dng 2 thnh phn Apply v Function. Vi 8 thn phn c th la chn trong lc trn ta ch c th chn 1 loi c xut hin trong thn phn condition. Tuy nhin vi thnh phn Apply c th Apply cho nhiu thuc tnh nh trn. Thc Tp Cng Ngh Phn Mm GEO-XACML Page 24

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+ c t vi cc Permission khng gian c t cc permissions truy cp d liu s dng GeoXACML, mt quyt nh cp quyn s phi tun theo cc quy tc nh nh ngha trong XACML. Trong ngha , s khc bit trong GeoXACML l n cung cp s m t cho cc rng buc v khng gian, s dng cc thuc tnh v cc hm hnh hc gii quyt cc mi quan h khng gian gia mt resource hnh hc v mt permission hnh hc. Mi permission c din t bi mt thnh phn cha mt thnh phn khng bt buc . Thnh phn ny l thnh phn din t cc permission v khng gian, thng qua cc hm khng gian . Mi hm trong s c 2 thng s truyn vo l