Tables

1. Tables Lecture 10

2. Tables & Attributes • Attribute Tables • Querying Data • Identifying Features • Selecting Features Interactively • Selecting Features by Attributes • Finding Features • Creating Tables • Microsoft Access • Join • Relate • Cardinality

3. Attribute Tables • To open an attribute table • Right click on the layer • Click on “Open Attribute Table”

4. Each Column is a Field Each Row is a Record Optional Information Required information FID Feature ID # SHAPE Type of Feature (Point, Line, Polygon) Contains X,Y Coordinate Info.

5. Querying Data • Identify Feature Tool • Turns cursor into query tool for identifying data associated with map elements and features. • Click on the Identify Feature Tool • Click on the map element • Item in the Attribute Table will be highlighted • Selecting Features Interactively • Click on the “Select Features” Tool • Click on multiple features to highlight the records in the attribute table. • At the bottom of the attribute table, click “Selected” to only show selected Records.

6. Selecting Features by Attribute • Using SQL (Structured Query Language) to select features by criteria. • Click on the “Selection” menu • Click on “Select by Attributes” • Click on the “Layer” drop down menu to select the layer you want. • Create a selection string by clicking on and typing in the Fields and Values.

7. Finding Features • Allows for query of data or features by name. • Search a layer or an attribute field for a value and highlights it on the map and attribute table. • Click on “Find” Tool • In the “Find” dialog box, select the layer and the attribute you want to find. • Click on the “Find” button • Right click on one or more items that are in objects found box. • Select the action that ypu want to occur with that item. • Flash Feature • Zoom to Feature • Identify Feature • Set Bookmark • Select Feature • Unselect Feature • Select Feature will cause the appropriate features to be highlighted on the map, and the records will be highlighted in the attribute table.

8. Microsoft Access or other Database Programs • Building a table outside of ArcGIS • Save as a .mdb (microsoft database) file • This is non-spatial data • Attach to a shapefile • The Database becomes queryable

9. Join • One to one cardinality - relationship between two tables. • One record in the first table is common with only one record in the second table. • The two tables are hooked together and a new table formed. Table from ArcGIS Desktop Help, (ESRI, Inc)

10. Steps to Join a table • Right click on the first layer • Click on “Joins and Relates” in the context menu. • Click on “Join” • In the drop down list choose the files and fields that you will join. • Click “OK” • Click “Yes” to build an index in the new table. • The new table is created.

11. Relate • One to many cardinality. • One record in the first table is common with more than one record in the second table. • The tables are linked, but remain separate. Table rrom Getting to Know ArcGIS desktop, Pg. 227

12. Steps to Relate a table • Right click on the first layer • Click on “Joins and Relates” in the context menu. • Click on “Relate” • In the drop down list choose the files and fields that you will relate. • Click “OK” • Now when you select a feature and open the attribute table. • Click “Options” at the bottom of the window • Choose “Related Tables” and click the name of the related table. • A new attribute table opens with the selected records highlighted.

13. Cardinality • The number of elements in a set or group. • If a table has a cardinality of 1:1 • (A common field in both tables) • One record in the first table relates to one record in the second table. • Join

14. If a table has a cardinality of 1:many • One record in the 1st table relates to many records in the 2nd table. • Relate