1. Introduction to ArcGIS for Environmental Scientists Module 2 – Fundamentals Lecture 6 – Table Functions

2. 6-1 Introduction to ArcGIS Chapter 6 Objectives Table properties and functions Field functions Graphs and reports Cardinality and table relationships

3. 6-2 Introduction to ArcGIS Structure Records (rows) Fields (attributes, columns, items) Field names must be unique and start with a letter Only letters, numbers and underscores are allowed in field names. Aliases may contain other characters Alias

4. 6-3 Introduction to ArcGIS Table Characteristics Layer attribute tableStand-alone table Relationship to spatial data One record per feature None Object ID and Shape fields required? YesNot required, usually not present FormatsGDB, dBase, INFOGDB, dBase, INFO, Excel*, Text*, Access* * Not editable in ArcGIS All tables may be opened in ArcMap or previewed in ArcCatalog

5. 6-4 Introduction to ArcGIS Table Functions Operations that work with the entire table Queries Change schema or appearance Manage relationships Create graphs and reports Export all or selected records to new table

6. 6-5 Introduction to ArcGIS Field Functions Operations that mostly work with single fields Sort (based on up to four fields) Summarize by unique values in a field (creates a new table) Summary statistics Change schema or appearance Properties – define alias, set field visibility or make field the Primary Display Field

7. 6-6 Introduction to ArcGIS Table Relationships Datasets with large numbers of attributes are often stored in several tables for management efficiency and ease of use Many applications require ancillary data stored in stand- alone tables There are two methods to combine tables – joins and relates The cardinality, or relationship of how records in different tables match, determines which method is used

8. 6-7 Introduction to ArcGIS Joins One-to-one and many-to-one matches use joins For each record, all fields from the matching record in the joined table are appended Join is virtual, stored in the map, not on disk Joins can be made permanent by exporting to a new table or feature class Appended fields can be used to label, symbolize, query or analyze as if they were part of the original table

9. 6-8 Introduction to ArcGIS 1 to 1 Join

10. 6-9 Introduction to ArcGIS Spatial Joins When feature classes do not share attributes, but do share location Like table joins, spatial joins work on one-to-one and one-to- many relationships Creates a new feature class with attributes from both input feature classes Commonly used to add attributes to points from: – polygons they fall within – lines or points they are nearest to

11. 6-10 Introduction to ArcGIS Relates One-to-many and many-to-many matches use relates For each selected record, all matching records in the related table are selected To refresh the display of related selections, go to Options>Related Tables>[Relate Name]

12. 6-11 Introduction to ArcGIS Many to Many Relate Reachcode used as key field in both tables

13. 6-12 Introduction to ArcGIS Graphs and Reports Both are created from selected records in a table – if nothing is selected, the entire table is used A wizard interface is used to choose graph style (pie, bar, etc.) and report formatting

14. 6-13 Introduction to ArcGIS Graphs May be added to layouts or saved as images

15. 6-14 Introduction to ArcGIS Reports Can be constructed using the built-in ArcMap Report Writer or Crystal Reports May be added to layouts, printed or exported to PDF, RTF or text files.