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Tables Recall...... A view displays features A feature is a geographic component of a theme and must have attributes to have significant meaning......

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Presentation on theme: "Tables Recall...... A view displays features A feature is a geographic component of a theme and must have attributes to have significant meaning......"— Presentation transcript:

1 Tables Recall A view displays features A feature is a geographic component of a theme and must have attributes to have significant meaning The feature is linked to the view The table contains/stores these attributes, that are then linked to the features.....

2 Linked Tables Linked implies that there must be some way of associating the attributes in the table to the features in the view... Tables may be in several forms: –Text files -.txt –Data Base files -.dbf –Other types of data bases - Oracle, Informix, etc.....

3 Getting to the Table Theme Table Button

4 The Table Records Attributes

5 Identifying Features/Attributes You are extracting a record...

6 Select Information from the Table Select Feature Tool Used

7 Querying

8 Or..... Query Tool

9 Query Builder

10 Build A Query.... Note the quotes... Double Click Logical Expressions All Values of State Names - in the DBF

11 The Result....

12 Once these Records are Selected You may Promote You may Extract - save as a new theme Graph Export Zoom to Selected etc.....

13 Promote

14 New Theme/Shapefile

15 There it is..

16 Attributes and all.... Attributes of Theme6.shp

17 Graph/Chart...

18 Charting....

19 The Chart

20 Sort

21 Export

22 File Type

23 Yet to Cover - Regarding Tables Some Merging & Union Features Linking Importing/Adding Data Base access Editing

24 Tables, cont... Get Statistics Summarize Merge

25 Statistics Get statistics on 1990 Population of ALL States

26 How to do it...

27 The result

28 Combine Query & Statistics

29 Result of the Query

30 Promote....

31 And get Statistics.... Note that the COUNT is now 7

32 Summarizing Very powerful and needed tool Allows user to produce a table of summary values... Can be summarized by a variety of methods : average, sum, standard deviation, etc... Lets look at an example......

33 Sub-regional Summarization The U.S. is divided into sub-regions.. The mid-Atlantic, Pacific, Mountain, etc... Lets find the total population in each of those sub-regions The sub-regions

34 Sub-regions

35 Activate Theme Table and Select SUMMARIZE From Field Menu Sub-region field is ACTIVE summarize

36 Summarize Window By summing Population 1990 will be summarized Default table name - change it if you like... Default table field name.. Recall we are summarizing by sub-region

37 The Result....

38 Graph the Result.....

39 Merging Features.... All features in the theme that have a common value within some field are merged to become a single theme. Polygons may be discontinuous (what does that mean?) This often makes managing data easier... Lets merge by sub-region...

40 From Summarize Window...

41 Results....

42 The Table...

43 Join & link

44

45

46 The Tables

47 Summarize by Name How many unique Names are there?

48 There are 4 unique county names Bedford Blair Fulton Huntingdon And how many TRIs are in each unique name?

49

50 Summarize Window By summing Population 1990 will be summarized Default table name - change it if you like... Default table field name.. Recall we are summarizing by sub-region

51 The data base file (dbf) There is no shape file at this point... What would the shape file do for us? What should you have done if you wanted to make a shapefile?

52 From Summarize Window...

53 I forgot to make the shapefile-- or I have a dbf that is related to an existing shapefile..... You may JOIN the tables.....

54 Recall the Tables Table you created....

55 Join.... How do I know which table gets added to the other?

56

57 This was a one-to-one join.... What if I have a situation with one- to-many?

58 For example...

59 LINK the tables for a one-to- many relationship... With the tables opened and the desired receiving table the active one - go to TABLE...LINK

60


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