Advanced SQL Selects
Download as PPT, PDF1 like1,160 views
The document provides details from the MapInfo User Conference 2014, focusing on advanced SQL selections and geographic operations using MapBasic functions. It includes exercises on calculating distances, areas, and lengths related to states and highways, as well as joining tables and utilizing sub-selections for spatial data analysis. It also outlines various SQL queries and their corresponding solutions for practical applications during the conference.
Advanced SQL Selects
- 1. Welcome MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC
- 2. Hands on Lab 13D Advanced SQL Selects Peter Horsbøll Møller GIS/LI Pre-Sales Specialist June 13, 2014 Every connection is a new opportunity™ MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC
- 3. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Advanced SQL Selects Practice calculating distances, object lengths and other geographic operations in SQL. Learn how to use Sub-selects and other advanced features.
- 4. Geographic Measurements MapBasic functions • Area(OBJ, ”units”) • ObjectLen(OBJ, ”units”) • Perimeter(OBJ, ”units”) • They also exist as Cartesian- & Spherical- versions • Units: ”m” MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC ”km” ”in” ”ft” ”mi” ... ”sq m” ”sq km” ”hectare” ”sq ft” ”sq mi” ...
- 5. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Exercise Data sets •USStates.tab •USUS_HIWay.tab •Calculate the area of each state •Calculate the perimeter of each state •Calculate the length of each highway
- 6. Aggregations and Grouping With the aggregations you can extract statistical information from a number of records, such as Sum, Average and Minimum or Maximum values The aggregations often take a column as parameter. Count(*), however, just takes a * If you use an aggregation you’ll get just one row in the result, unless you specify a column to group the result by MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC
- 7. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Exercise Data sets •USStates.tab •USUS_HIWay.tab •Calculate the total area of all states •Calculate the total area of the selected states •Calculate the total length of the selected highways
- 8. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Joining Tables When joining two tables thru a Select statement you need to specify a join condition This can be a alfanumerical join: • TABLE1.ID = TABLE2.ID or a spatial join: • TABLE1.OBJ Intersects TABLE2.OBJ The spatial object is taken from the first table in the join statement
- 9. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Exercise Data sets •USStates.tab •USUS_HIWay.tab •Find the spatial join between highways and states, that is which states does the highways intersect? •How much of each highway (in miles) is within the individual states?
- 10. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Sub Selections A Sub Selection returns a value or a list of values that can compared to bojects or alfanumerical values A sub select has this structure: Select * From TABLE1 Where COLUMN1 In (Select COLUMN1 From TABLE2) Or Select * From TABLE1 Where OBJ Intersects Any (Select OBJ From TABLE2)
- 11. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Exercise Data sets •USStates.tab •USUS_HIWay.tab •Find the states that has one or more highways crossing •Find the states that has no highways crossing
- 12. Measuring Distance MapBasic functions • Distance(xFrom, yFrom, xTo, yTo, ”units”) • Exists also as Cartesian- & Spherical- versions • Format$() • Can be used to forse a larger number of decimals: Format$(numeric_value, ”#.######”) • CentroidX(object) / CentroidY(object) • Extracts coordinates from the centroid of an object MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC
- 13. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Exercise Data sets •USStates.tab •USUS_HIWay.tab •USSTATECAP.tab •Find the distance from every state capital to Washington •Find the distance from every state capital to Nashville
- 14. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Solutions 1 Select State_Name , Area(obj, "sq mi") "Area sq miles" from STATES into Selection 2 Select State_Name , Area(obj, "sq mi") "Area sq miles" , Perimeter(obj, "mi") "Perimeter miles" from STATES into Selection 3 Select Highway , ObjectLen(obj, "mi") “Length miles” from US_HIWAY into Selection 4 Select Sum(Area(obj, "sq mi")) "Area sq miles" from STATES into Selection
- 15. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Solutions 5 Select Sum(Area(obj, "sq mi")) "Area sq miles" from Selection into __SUM 6 Select Sum(ObjectLen(obj, "mi")) “Length miles” from Selection into __SUM 7 Select US_HIWAY.Highway, STATES.State_Name from US_HIWAY, STATES where US_HIWAY.Obj Intersects STATES.Obj order by US_HIWAY.Highway, STATES.State_Name into Selection
- 16. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Solutions 8 Select US_HIWAY.Highway, STATES.State_Name , ObjectLen(Overlap(US_HIWAY.Obj, STATES.Obj), "mi") "Length Miles" from US_HIWAY, STATES where US_HIWAY.Obj Intersects STATES.Obj order by US_HIWAY.Highway, STATES.State_Name into Selection 9 Select State_Name from STATES where OBJ Intersects Any (Select OBJ From US_HIWAY) order by State_Name into Selection
- 17. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Solutions 10 Select State_Name from STATES where not OBJ Intersects Any (Select OBJ From US_HIWAY) order by State_Name into Selection
- 18. MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC Solutions 11 Set CoordSys Table STATECAP ‘Select Washinton Fetch First From Selection Print Format$(CentroidX(Selection.obj), "#.######") + ", " + Format$(CentroidY(Selection.obj), "#.######") Select Capital, State , Distance(-77.016167, 38.90505, CentroidX(OBJ), CentroidY(OBJ), "mi") "Distance To Washington" from STATECAP into Selection
- 19. Get the latest MapInfo User Conference news: Twitter via #MapInfoUC and follow us @MapInfo MapInfo User Conference 2014: GIS Gets Personal #MapInfoUC