Defined by coordinate Defined by coordinate. meaning, but is required for comparisons

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1 Developer s Guide to Native Spatial Types y SQL Server Tony Wakim Shannon Shields

2 Topics Introduction to SQL Server spatial types Geometry and Geography Using geography & geometry data Integration with ArcGIS Migration g tool SQL Server spatial indexes Architecture Tuning

3 Spatial data in SQL Server 2008 Microsoft provides two spatial data types GEOMETRY XY coordinates on a plane Supports geographic and projected coordinate systems GEOGRAPHY Latitude, longitude coordinates on an ellipsoid Supports only geographic coordinate systems Spatial reference must match SQL ServerServer-supported European Petroleum Survey Group (EPSG) codes defined in sys.spatial_reference_systems OGC compliant methods Implemented as.net CLR (UDT) data type Available in all 2008 editions except Compact

4 Comparing Geometry & Geography types ASPECT GEOMETRY GEOGRAPHY Line interpolation Cartesian Great Circle Spatial Domain Defined by coordinate system Sphere (Earth) Units from calculations Defined by coordinate Defined by coordinate system same as data system meters or units feet Supported coordinate systems t Any SRID SRID has h no inherent i h t meaning, but is required for comparisons Defined in sys.spatial_reference_ ti l f systems table

5 Built--in Spatial Type Support Built Treated like any other spatial storage type Added benefit is SQL access to simple features Use ArcGIS to create data Import, Copy/Paste or create new Feature Class Configuration keyword controls storage type Geometry keyword Geography keyword Spatial Index automatically created with default values

6 Using existing SQL Server spatial tables Integrate data created with other applications Use SQL to create table with Geometry or Geography columns l Access methods: ArcMap Query Layers (read(read-only) Register with Enterprise Geodatabase (read/write) sdelayer o register Register in ArcCatalog sdelayer o register l blocks,geog_col e an+c t GEOGRAPHY C objectid,sde G 4326 k GEOGRAPHY

7 Registration considerations Registration R i t ti pre pre--requisites i it Single spatial column Single entity type (point, line or polygon) Single coordinate reference (SRID) Registration does not add a spatial index or calculate a layer extent Use ArcCatalog to create index Use sdelayer o alter to calculate an extent Registration does not check for valid geometries

8 Migrating SDEBinary to Geometry or Geography Geoprocessing tool for in in--line conversion of SDEBinary data to SQL Server data types New at ArcGIS 10 Converts non non--versioned, versioned & archived data # Import arcpy module import arcpy # Local l variables: i bl inputdataset = "Database Connections\\gdb@gis1.sde\\gdb.Parcels" # Process: Migrate Storage arcpy.migratestorage_management( inputdataset, "GEOMETRY")

9 SQL Server spatial queries -- Select all rivers that intersect Sonora SELECT r.name, r.shape.stlength()/1000 Length_km, r.shape FROM gdb.rivers gdb rivers r WHERE (SELECT s.shape FROM gdb.states s WHERE name = 'Sonora').STIntersects(r.Shape) = 1

10 SQL Server Spatial Index Overview Modified Adjustable Quadtree 4 level hierarchical grid 3 densities per level low 16 cells (4x4) medium di 64 cells ll (8 (8x8) 8) high 256 cells (16x16) Cells per object: Tessellation rules Covering Cells Cells--perper-object Deepest cell

11 Index tessellation LOW LOW, LOW, LOW LOW, LOW LOW Cells/Object = 16 Object recorded in level 2 cells only Level 1 - low Level 2 low Total cells = 14 Level 3 low Total cells > 16 With medium or high g density, object recorded in level 1 cells Level 1 - medium Level 1 - high

12 Creating a SQL Server spatial index CREATE SPATIAL INDEX spidx p _g geometry y ON parcels (geometry_col) USING GEOMETRY_GRID WITH ( BOUNDING BOX = (0,0,500,200), GRIDS = (MEDIUM, MEDIUM, MEDIUM, MEDIUM), CELLS_PER_OBJECT = 16); Created by ArcGIS using feature class extent and dbtune parameters B_MS_SPINDEX and A_MS_SPINDEX A MS SPINDEX Extent (BOUNDING_BOX) calculated automatically properties p specified p in dbtune parameters p All other p

13 Sp help spatial index stored procedures Sp_help_spatial_index Returns metrics of index value for a supplied spatial filter Primary Filter efficiency Percentage of output rows selected by primary filter Higher is better - indicates fewer false positives processed by secondary filter Internal Filter efficiency Percentage of primary filter rows processed by internal filter Higher is better indicates index is avoiding more costly secondary filtering And much more see SQL Server Books Online for full list of properties

14 Spatial Index Tuning Demo Using sp_help_spatial_geometry_index output to evaluate spatial index performance Observe Ob performance f metrics t i for f spatial ti l index i d with very large bounding box Observe performance metrics for more performant spatial indexes

15 Related Content ArcGIS and Geodatabase Resource Centers Presentations: Accessing A i Y Your G Geodatabase d t b Outside O t id off ArcObjects A Obj t Wed 10:30am Primrose B (PSCC) Demo Theater Presentations Introduction to Query Layers Wed 4:00pm Theater 1 SQL Server 2008 Spatial p Data: SQL Server Books Online com/en-us/library/ms aspx us/library/ms aspx Spatial Indexing Overview