Working with Tables Where the serious GIS work

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 Owners. dbf Original Coffee Shop Attribute Table (points)

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 point 32456 Smith point 23412 Jones point 16534 Green ID 71 64 22 Join will combine for the first record and then ignore the rest. Relate will connect all the records. ID Tax_Val Income 71 1400 42000 723 5701 3218 89055 ? 64 127 879 22 465 2271 4213 120000 ? 71 64 ? 71

What happens if you join in a Many to One Shape point Point point Area 17864 22341 12221 32456 23412 16534 Name Allan Rios Lee Smith Jones Green Route 14 14 9 9 27 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

Related Tables

Summarize Data

Create a Graph from Summarized, Selected Data

Chart of joined, summarized, selected data.