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Object Relational Model Spatial Queries

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Query Model Spatial Layer Data Table where coordinates are stored Primary Filter Spatial Index Index retrieves area of interest (window) Reduced Data Set Secondary Filter Spatial Functions Procedures that determine exact relationship Exact Result Set

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Spatial Operators vs Functions Spatial operators:Spatial operators: –Take advantage of spatial indexes –Require that spatial index exists on the first geometry specified in the operator. Spatial Functions: Spatial Functions: –Do not take advantage of spatial indexes –Could be used on small tables that are not spatially indexed Spatial operators:Spatial operators: –Take advantage of spatial indexes –Require that spatial index exists on the first geometry specified in the operator. Spatial Functions: Spatial Functions: –Do not take advantage of spatial indexes –Could be used on small tables that are not spatially indexed

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Spatial Operators vs Functions SDO_RELATE –Performs a primary and secondary filter SDO_WITHIN_DISTANCE –Gets all geometries that are within some distance from a selected geometry SDO_NN –Gets the ‘n’ closest geometries SDO_RELATE –Performs a primary and secondary filter SDO_WITHIN_DISTANCE –Gets all geometries that are within some distance from a selected geometry SDO_NN –Gets the ‘n’ closest geometries SDO_GEOM.RELATE –To determine the relationship between two geometries –To perform a spatial query without using a spatial index (I.e. on a small table) SDO_GEOM.WITHIN_DISTANCE –Generates a buffer around a geometry and performs a secondary filter OperatorsFunctions

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Spatial Operators

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The SDO_RELATE operator boolean := SDO_RELATE (,, ‘MASK= QUERYTYPE= [other optional parameters]’ ) boolean := SDO_RELATE (,, ‘MASK= QUERYTYPE= [other optional parameters]’ ) Performs an exact query (primary and secondary filter) Returns TRUE or FALSE Performs an exact query (primary and secondary filter) Returns TRUE or FALSE

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Required arguments GEOMETRY-1 –A column of type SDO_GEOMETRY GEOMETRY-2 –Variable or column of type SDO_GEOMETRY MASK –Identify spatial relationship to test QUERYTYPE –Valid values are JOIN or WINDOW GEOMETRY-1 –A column of type SDO_GEOMETRY GEOMETRY-2 –Variable or column of type SDO_GEOMETRY MASK –Identify spatial relationship to test QUERYTYPE –Valid values are JOIN or WINDOW

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A B A B A B A B A B A red B green A B B Inside A A Contains B B Covered by A A Covers B Touch Overlap Boundaries Intersect Overlap Boundaries Disjoint Equal Disjoint Topological relationships

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1.DISJOINT: boundaries and interiors do not intersect 2. TOUCH: boundaries intersect but interiors do not intersect 3. OVERLAPBDYDISJOINT: interior of one object intersects boundary and interior of other object, but two boundaries do not intersect (example: a line originates outside a polygon and ends inside the polygon) 4. OVERLAPBDYINTERSECT: boundaries and interiors of the two objects intersect 5. EQUAL: the two objects have the same boundary and interior Topological relationships

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6. CONTAINS: interior and boundary of one object is completely contained in the interior of other object 7. COVERS: interior of one object is completely contained in interior of other object and their boundaries intersect 8. INSIDE: opposite of CONTAINS; A INSIDE B implies B CONTAINS A 9. COVEREDBY: opposite of COVERS; A COVEREDBY B implies B COVERS A 10. ANYINTERACT: the objects are non-disjoint Topological relationships (cont.d)

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select c.city, c.pop90 from cities c where sdo_relate ( c.location, mdsys.sdo_geometry (2003, null, null, mdsys.sdo_elem_info_array (1,1003,3), mdsys.sdo_ordinate_array (-109,37,-102,40)), 'mask=ANYINTERACT') = 'TRUE'; select c.city, c.pop90 from cities c where sdo_relate ( c.location, mdsys.sdo_geometry (2003, null, null, mdsys.sdo_elem_info_array (1,1003,3), mdsys.sdo_ordinate_array (-109,37,-102,40)), 'mask=ANYINTERACT') = 'TRUE'; SDO_RELATE - An example Find all cities in a selected rectangular area

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select c.county, c.state_abrv from counties c, states s where s.state = 'New Hampshire' and sdo_relate (c.geom, s.geom, 'mask=INSIDE+COVEREDBY querytype=WINDOW') = 'TRUE'; select c.county, c.state_abrv from counties c, states s where s.state = 'New Hampshire' and sdo_relate (c.geom, s.geom, 'mask=INSIDE+COVEREDBY querytype=WINDOW') = 'TRUE'; SDO_RELATE - A window query Find all counties in the state of New Hampshire

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select c1.county, c1.state_abrv from counties c1, counties c2 where c2.state = 'New Jersey' and c2.county = 'Passaic' and sdo_relate (c1.geom, c2.geom, 'mask=TOUCH querytype=WINDOW') = 'TRUE'; select c1.county, c1.state_abrv from counties c1, counties c2 where c2.state = 'New Jersey' and c2.county = 'Passaic' and sdo_relate (c1.geom, c2.geom, 'mask=TOUCH querytype=WINDOW') = 'TRUE'; SDO_RELATE - Another window query Find all counties around county Passaic

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SDO_RELATE - join vs window query Find all interstates that cross county Passaic in NJ Find all interstates that cross a county in Arizona with pop density <10 This requires compatible indexes on the layers ! Find all interstates that cross county Passaic in NJ Find all interstates that cross a county in Arizona with pop density <10 This requires compatible indexes on the layers ! select i.interstate from interstates i, counties c where c.state = 'New Jersey' and c.county = ‘Passaic’ and sdo_relate (i.geom, c.geom, 'mask=ANYINTERACT querytype=WINDOW') = 'TRUE'; select i.interstate from interstates i, counties c where c.state = 'New Jersey' and c.county = ‘Passaic’ and sdo_relate (i.geom, c.geom, 'mask=ANYINTERACT querytype=WINDOW') = 'TRUE'; select i.interstate from interstates i, counties c where c.state = 'Arizona' and c.poppsqmi < 10 and sdo_relate (i.geom, c.geom, 'mask=ANYINTERACT querytype=JOIN') = 'TRUE'; select i.interstate from interstates i, counties c where c.state = 'Arizona' and c.poppsqmi < 10 and sdo_relate (i.geom, c.geom, 'mask=ANYINTERACT querytype=JOIN') = 'TRUE';

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Optional arguments IDXTAB1 –Index table to associate with first geometry in operator. –By default, the primary index table is used. IDXTAB2 –Index table to associate with the second geometry in operator –By default, the primary index table is used. –Only supported if QUERYTYPE=JOIN IDXTAB1 –Index table to associate with first geometry in operator. –By default, the primary index table is used. IDXTAB2 –Index table to associate with the second geometry in operator –By default, the primary index table is used. –Only supported if QUERYTYPE=JOIN

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The SDO_WITHIN_DISTANCE operator boolean := SDO_WITHIN_DISTANCE (,, ‘DISTANCE=, QUERYTYPE= [other optional parameters]’ ) boolean := SDO_WITHIN_DISTANCE (,, ‘DISTANCE=, QUERYTYPE= [other optional parameters]’ ) Performs an exact or approximate query Euclidean distance only Returns TRUE or FALSE Performs an exact or approximate query Euclidean distance only Returns TRUE or FALSE

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Arguments GEOMETRY-1 –A column of type SDO_GEOMETRY GEOMETRY-2 –Variable or column of type SDO_GEOMETRY DISTANCE (required) –The distance (expressed in the units used for the coordinate system) QUERYTYPE (optional) GEOMETRY-1 –A column of type SDO_GEOMETRY GEOMETRY-2 –Variable or column of type SDO_GEOMETRY DISTANCE (required) –The distance (expressed in the units used for the coordinate system) QUERYTYPE (optional)

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Find all cities within a distance from an interstate Find interstates within a distance from a city Find all cities within a distance from an interstate Find interstates within a distance from a city select c.city, c.state_abrv from cities c, interstates i where highway = ‘I4’ and sdo_within_distance ( c.location, i.geom,‘distance=0.5') = 'TRUE'; select c.city, c.state_abrv from cities c, interstates i where highway = ‘I4’ and sdo_within_distance ( c.location, i.geom,‘distance=0.5') = 'TRUE'; SDO_WITHIN_DISTANCE Examples select i.highway from interstates i, cities c where city = 'Tampa' and sdo_within_distance ( i.geom, c.location,'distance=0.5') = 'TRUE'; select i.highway from interstates i, cities c where city = 'Tampa' and sdo_within_distance ( i.geom, c.location,'distance=0.5') = 'TRUE';

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Find all cities within a distance from a state Also returns all cities in Florida ! Find all cities within a distance from a state Also returns all cities in Florida ! select c.city, c.state_abrv from cities c, states s where s.state='Florida' and sdo_within_distance ( c.location, s.geom, 'distance=1.5') = 'TRUE'; select c.city, c.state_abrv from cities c, states s where s.state='Florida' and sdo_within_distance ( c.location, s.geom, 'distance=1.5') = 'TRUE'; SDO_WITHIN_DISTANCE Examples

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The SDO_NN operator boolean := SDO_NN (,, ‘SDO_NUM_RES=, [other optional parameters]’ ) boolean := SDO_NN (,, ‘SDO_NUM_RES=, [other optional parameters]’ ) Calculates the N closest geometries Euclidean distance only Returns TRUE or FALSE Calculates the N closest geometries Euclidean distance only Returns TRUE or FALSE

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Arguments GEOMETRY-1 –A column of type SDO_GEOMETRY GEOMETRY-2 –Variable or column of type SDO_GEOMETRY SDO_NUM_RES (required) –Number of objects to select GEOMETRY-1 –A column of type SDO_GEOMETRY GEOMETRY-2 –Variable or column of type SDO_GEOMETRY SDO_NUM_RES (required) –Number of objects to select

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Find the 5 nearest cities from Orlando select c1.city, c1.state_abrv from cities c1, cities c2 where c2.city = 'Orlando' and sdo_nn ( c1.location, c2.location, 'sdo_num_res = 6') = 'TRUE' and c1.rowid <> c2.rowid; select c1.city, c1.state_abrv from cities c1, cities c2 where c2.city = 'Orlando' and sdo_nn ( c1.location, c2.location, 'sdo_num_res = 6') = 'TRUE' and c1.rowid <> c2.rowid; SDO_NN Example

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Find the 10 nearest cities from Orlando ordered by distance select c1.city, c1.state_abrv, sdo_geom.sdo_distance ( c1.location, c2.location, 0.005) distance from cities c1, cities c2 where c2.city = 'Orlando' and sdo_nn ( c1.location, c2.location, 'sdo_num_res = 11') = 'TRUE' and c1.rowid <> c2.rowid order by distance; select c1.city, c1.state_abrv, sdo_geom.sdo_distance ( c1.location, c2.location, 0.005) distance from cities c1, cities c2 where c2.city = 'Orlando' and sdo_nn ( c1.location, c2.location, 'sdo_num_res = 11') = 'TRUE' and c1.rowid <> c2.rowid order by distance; SDO_NN Example

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