Working with Tables

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Working with Tables

• Where the serious GIS work takes place.

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One Feature One Record
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Field or Column
Record or Row
One Feature One Record
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Field Requirements

• Use unique column names
• Define the data type to be stored
• Appropriate width for attribute value.

Data Types will be discussed in the next lecture.
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Joining and Relating Tables
A Common Field
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One to One Relationship
Join the tables.
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Many to One
Join the tables.
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One to Many Relationship
Relate the tables.
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Many to Many
Relate the tables.
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Joining Tables
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Joining to another table based on atributes.
This is the table you are joining
These are the common fields
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Join Results
Original Owners.dbf
Original Coffee Shop Attribute Table (points)
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Joined Tables

• The originals remain separated
• They can be unjoined
• You can use joined data to symbolize and
  classify.
• You can create statistics, charts and reports.

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What happens if you join when you should relate
for a One to Many?
Shape Area Name ID
point 32456 Smith 71
point 23412 Jones 64
point 16534 Green 22
ID Tax_Val Income
71 1400 42000
71 723 5701
64 3218 89055
64 127 879
22 465 2271
71 4213 120000
?
?
Join will combine for the first record and then
ignore the rest. Relate will connect all the
records.
?
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What happens if you join in a Many to One
Shape Area Name Route
point 17864 Allan 14
Point 22341 Rios 14
Point 12221 Lee 9
point 32456 Smith 9
point 23412 Jones 27
point 16534 Green 27
Route Day Comp
14 M UPS
9 T FEDX
27 F AIRB
The records are duplicated in the Joined file
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Multiple Joins and Relates(Daisy Chains)
Route
Route
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Related Tables
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Summarize Data
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Create a Graph from Summarized, Selected Data
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(No Transcript)
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Chart of joined, summarized, selected data.