1. ESRM 250/CFR 520 Autumn 2009 Phil Hurvitz
Tables
ESRM 250/CFR 520 Autumn 2009
Phil Hurvitz
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2. Using ArcMap tables Querying tables Table relationships
Overview
Using ArcMap tables
Querying tables
Table relationships
Graphs from tables
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3. Using ArcMap tables: Introduction
Tables are just as important as coordinate (map) data
Tables are used to hold attribute data
Tables can be used to hold data that are not explicitly spatial in nature
Tables are the source of all basic statistics
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4. Using ArcMap tables: Overview
Creating tables from existing sources
Creating a new table
Adding fields (columns) to tables
Adding records (rows) to tables
Editing values in table records
Calculating fields
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5. Creating tables from existing sources
Tables can be created from existing sources:
dBase files
ASCII files (tab or comma delimited)
INFO files
ODBC connections
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6. Creating tables from ODBC connections
Tabular data can be obtained from ODBC databases (e.g., Oracle, Access)
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7. New (dBase, GDB) tables can be created from scratch
Creating a new table
New (dBase, GDB) tables can be created from scratch
Creates a new file on disk
New table is empty
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8. Adding fields to tables
Each field must be defined at add time
Data type and storage parameters need to be defined
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9. Tips for defining fields
Field data types should match the data they will store
Short Integer: Whole numbers from -32,768 to 32,768
Long Integer: Whole numbers from -2,140,000,000 2,140,000,000
Float: single-precision floating-point numbers with an accuracy to 6 places past the decimal
Double: double-precision floating-point numbers with an accuracy to 15 places past the decimal
Date: January 1, 0100 to December 31, 9999
Text: characters
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10. Tips for defining fields
Precision = number of digits
Scale = digits to the right of the decimal point
e.g.,
precision = 5
scale = 2
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11. Adding records to tables
Records can be added ad hoc to stand-alone tables
Do not add records to feature data (point, line, polygon) tables
Adding features (feature editing) will automatically add a record to the feature attribute table
Adding records to feature attribute tables will result in “phantom” records that are not associated with shape features
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12. Adding records to tables
Records can be added ad hoc to stand-alone tables
New records will have null values for all fields until updates are made
new record
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13. Values in a new field can be generated based on calculated expressions
Calculating fields
Values in a new field can be generated based on calculated expressions
Expressions can use other fields
Acts on selected set of records
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14. Using ArcMap tables Querying tables Table relationships
Overview
Using ArcMap tables
Querying tables
Table relationships
Graphs from tables
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15. Displaying selected sets Modifying selected sets
Querying tables
Making queries
Sorting records
Displaying selected sets
Modifying selected sets
Basic descriptive statistics
Table summaries
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16. Select records from tables
Making queries
Select records from tables
“Select by attributes”
Graphical interface to table data
Selected records in cyan
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17. Displaying selections
Displaying selected records will show only those records that are in the selected set
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18. Record can be sorted ascending or descending by field
Sorting records
Record can be sorted ascending or descending by field
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19. Displaying selected sets
Selecting records from feature tables also selects features from layers (and vice versa)
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20. Modifying selected sets
Existing selections can be broadened or narrowed
Additional query criteria
Add to selection
Remove from selection
Further narrow down current selection
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21. Basic descriptive statistics
Basic descriptive statistics can be generated for a field
will describe selected set (or all records if there is no active selection)
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22. Summarizing tables Creates a new table
Table summaries
Summarizing tables
Creates a new table
Summarizes values in numeric fields by values in a categorical field
One output record per unique value in the (categorical) field of interest
Different summary statistics available
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23. Table summaries
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24. Using ArcMap tables Querying tables Table relationships
Overview
Using ArcMap tables
Querying tables
Table relationships
Graphs from tables
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25. Record relationships among tables
One-to-one relationship
every record in Table A has a matching value in Table B
Table B
Table A
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26. Record relationships among tables
Many-to-one relationship
Many records in Table A have a match with only 1 record in Table B
Table A
Table B
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27. Record relationships among tables
One-to-many relationship
Only 1 record in Table B has a match with many records in Table B
Table A
Table B
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28. Creates a virtual join (does not alter data sources)
Joining tables
Creates a virtual join (does not alter data sources)
Used for:
one-to-one
many-to-one
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29. Does not join, but allows simultaneous selections
Relating tables
Does not join, but allows simultaneous selections
Used for:
one-to-one
many-to-one
one-to-many
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30. Relating tables
“Relate” updates the selection on the related table based on field relationships
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31. Using ArcMap tables Querying tables Table relationships
Overview
Using ArcMap tables
Querying tables
Table relationships
Graphs from tables
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32. Making graphs from tables
What are graphs?
Creating graphs from tables
Graph elements
Graph types
Graph legends
Axis properties
Axis increments and grid lines
Displaying multiple fields
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33. Graphical representation of tabular data
What are graphs?
Graphical representation of tabular data
numbers can be
difficult to interpret
graphs are easier to interpret
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34. Graphs are dynamically linked to tables
What are graphs?
Graphs are dynamically linked to tables
A selection on the table will be reflected in the graph
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35. Creating graphs from tables
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36. Creating graphs from tables
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37. Graphs have many elements to format
Graph elements
Graphs have many elements to format
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38. A number of different types and subtypes of graphs exist
Graph types
A number of different types and subtypes of graphs exist
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39. X and Y axes have various properties
Axis properties
X and Y axes have various properties
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40. Axis increments and grid lines
Increments and grid lines can be formatted in different ways
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41. Axis increments and grid lines
A maximum value can be specified
Be careful, the graph no longer shows the data range
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42. Displaying multiple fields
Multiple fields can be displayed in the graph
Comparison of variables
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