1. Aspatial Selection

2. Table Queries Table queries are a very common GIS aspatial operation Selects a subset of records based on values of specific attributes Uses Set Algebra and Boolean Operators

3. Set Algebra

4. Set Algebra uses operations: – Less than* < – Greater than* > – Equal to* = – Not equal to Greater Than and Less Than may not be applied to nominal attributes. – Why? *May be applied alone or in combination

5. “Male Population” > “Female Population”“Population” > 7,000,000 “Region” <> ‘Mountain’“State Name” = ‘South Dakota’

6. Boolean Algebra

7. Uses conditions OR, AND, and NOT Evaluated by assigning an outcome, true or false, to each condition Order of operations do matter Boolean operators are not distributable

8. Truth Tables XYR FFF TFF FTF TTT XYR FFF TFT FTT TTT AND OR XR TF FT NOT Order of Operations: Parenthesis/Brackets -> NOT -> AND -> OR

9. What are the results? NOT (F) T AND T F OR NOT(T) T OR (F OR (T AND T) ( T AND T) OR F AND (NOT(F) AND T )

10. What are the results? NOT (F)  True T AND T  True F OR NOT(T)  False T OR (F OR (T AND T))  True ( T AND T) OR F AND (NOT(F) AND T )  True

11. CountryPopulation 2009 Unemployment (%) UN Member Gyruss67,8372.1N Pengo5,250,2758.5Y Galaxian30,1673.1Y Tempest2,461,26719N Zaxxon14,01990Y (UN Member = “Y” OR UN Member = “N”) AND Unemployment > 3.5 Note: Data is fictitious

12. (UN Member = “Y” OR UN Member = “N”) AND Unemployment > 3.5 Note: Data is fictitious Answer: Pengo, Tempest, Zaxxon CountryPopulation 2009 Unemployment (%) UN Member Gyruss67,8372.1N Pengo5,250,2758.5Y Galaxian30,1673.1Y Tempest2,461,26719N Zaxxon14,01990Y

13. Population > 80,000 AND Unemployment < 6 Note: Data is fictitious CountryPopulation 2009 Unemployment (%) UN Member Gyruss67,8372.1N Pengo5,250,2758.5Y Galaxian30,1673.1Y Tempest2,461,26719N Zaxxon14,01990Y

14. Population > 80,000 AND Unemployment < 6 Note: Data is fictitious Answer: NULL (nothing was selected) CountryPopulation 2009 Unemployment (%) UN Member Gyruss67,8372.1N Pengo5,250,2758.5Y Galaxian30,1673.1Y Tempest2,461,26719N Zaxxon14,01990Y

15. NOT(Population 31,000) AND UN Member = “Y” Note: Data is fictitious CountryPopulation 2009 Unemployment (%) UN Member Gyruss67,8372.1N Pengo5,250,2758.5Y Galaxian30,1673.1Y Tempest2,461,26719N Zaxxon14,01990Y

16. NOT(Population 31,000) AND UN Member = “Y” Note: Data is fictitious Answer: Pengo, Zaxxon, Galaxian CountryPopulation 2009 Unemployment (%) UN Member Gyruss67,8372.1N Pengo5,250,2758.5Y Galaxian30,1673.1Y Tempest2,461,26719N Zaxxon14,01990Y