Working with Tables

Where the serious GIS work takes place.

One Feature – One Record

Field

or

Column

Record

or

Row

One Feature – One Record

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.

Joining and Relating Tables

A Common Field

One to One Relationship

Join the tables.

Many to One

Join the tables.

One to Many Relationship

Relate the tables.

Many to Many

Relate the tables.

Joining Tables

Joining to another table based on atributes.

This is the table you are joining

These are the common fields

Join Results

Original Coffee Shop Attribute Table (points)

Original Owners.dbf

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.

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.

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

Multiple Joins and Relates(Daisy Chains)

Route

Route

Related Tables

Summarize Data

Create a Graph from Summarized, Selected Data

Chart of joined, summarized, selected data.