1. Who Needs Google Maps? (when you’ve got SQL Server)
Alastair Aitchison

2. Route between locations
Google Maps
Snazzy Logo
Search for Location
Map Display
Route between locations

3. Route between locations
Bing Maps
Snazzy Logo
Search for Location
Map Display
Route between locations

4. Route between locations
Yahoo Maps
Snazzy Logo
Route between locations
Map Display
Search for Location

5. Route between locations
MapQuest
Snazzy Logo
Search for Location
Route between locations
Map Display

6. Requirements Checklist
Snazzy Logo
Pannable, Zoomable Map Display
Search for a Location
Calculate Route Between Destinations
This will involve: Importing data from shapefiles, integrating with SQLCLR, using SSRS, passing spatial data to/from stored procedures, and more!

7. Requirement #1 : Snazzy Logo
Take a brand name and add on “maps”
Therefore…

8. Requirements Checklist
Snazzy Logo a
Pannable, Zoomable Map Display
Search for a Location
Calculate Route Between Destinations

9. Ordnance Survey Open Data
Free, “lite” OS datasets
Different products, e.g:
VectorMap (features)
Gazetteer (placenames)
CodePoint Open (p’codes)
Download or DVD
ESRI Shapefile format

10. Loading Shapefiles to SQL Server
SQL Server does not support shapefiles
Use 3rd party tools
Commercial: Safe FME, Manifold
Free: OGR2OGR, Shape2SQL
Check .prj file to determine geography/geometry and correct SRID

11. Shape2SQL Demo

12. Requirement #2 : Map Display
What visualisation options does SQL Server provide?
SSMS Spatial Results tab (SQL 2008/R2)
SSRS Map Component (SQL 2008 R2 only)
No new options in SQL Denali

13. SSMS Spatial Results Tab Demo

14. SSRS Map Component Demo

15. Requirement #2 : Map Display
SSMS Spatial Results tab
+ Available after SELECTing geometry/geography data
+ Pannable, zoomable, labelled
- Max 5,000 features
- Only for use in SSMS - not embeddable / exportable
SSRS Map Component (SQL 2008 R2)
+ Good for analysis – drilldown by clicking shapes etc.
+ Can be exported as static image
Slow and static. Not “slippy” interface

16. A Silverlight Map Display App
Silverlight provides UI and Graphics classes
SqlServer.Types.dll not Silverlight compatible
Use intermediary web service
OS Eastings / Northings -> Screen (x,y)

17. SProc to Retrieve OS Tiles
CREATE PROCEDURE geometry AS BEGIN float = float / 256; SELECT FROM Settlement_Area WITH(index(geom27700_sidx)) WHERE = 1 END

18. Silverlight Slippy Map Demo

19. Requirements Checklist
Snazzy Logo a
Pannable, Zoomable Map Display a
Search for a Location
Calculate Route Between Destinations

20. Geocoding (Location Searching)
Not really a Spatial Operation
Address text parsing / search
SELECT * FROM OSLocator
WHERE ROADNAME
Fuzzy matching with full-text search
RegEx matching for Postcode
Supplied address is freetext user input so be cautious of SQL injection attacks etc.

21. Geocoding Demo

22. Requirements Checklist
Snazzy Logo a
Pannable, Zoomable Map Display a
Search for a Location a
Calculate Route Between Destinations

23. Routing Not sufficient to have a table of LineStrings
Network topology – how are roads connected?
Graph theory:
Node (Point)
Edge (LineString)

24. Brute Force Routing with T-SQL
Recursive CTE
Anchor member selects LineString edges that begin at chosen start node
Recursive member joins from STEndPoint() of last edge to STStartPoint() of next edge
Create geometry of route already travelled to avoid infinite loops
Expand outwards until end node found

25. Smart Routing with SQLCLR
A* algorithm
Heuristics prioritise edges more likely to lie on least cost route to goal
“Least cost” does not have to mean “shortest”
Additional properties of each node:
g: cost of route already travelled to reach this node
h: estimated remaining cost from this node to goal
f: g + h

26. A* Algorithm in OperationB C
Start D
Goal E

27. A* Algorithm in OperationB C
8.2
2.8
Start D
Goal 3 7 2
10.2 E

28. A* Algorithm in OperationB C
8.2
2.8
Start D
Goal X 2
10.2 E

29. A* Algorithm in OperationB C 1
8.5
2.8
Start D
Goal X 2
10.2 E

30. A* Algorithm in OperationB C 1
8.5
2.8
Start D
Goal X 2
10.2
Goal reached!
Route cost: 12.2 E

31. Requirements Checklist
Snazzy Logo a
Pannable, Zoomable Map Display a
Search for a Location a
Calculate Route Between Destinations a
Put it all together and what have you got?

32. SQLBitMaps in action…

33. Want More?
#sqlbits8 : MSDN Spatial Forum: