1. Feature Classes, Data File Formats in ArcGIS

2. Feature Class
A single geographic feature type (having the same spatial representation) corresponds to a feature class
Feature classes in geodatabase are:
Point feature class
Line feature class
Polygon feature class
Annotation
Geographic feature type (counties, roads, capitals, etc.)
Collection of geographic features with same geometry type.
manhole cover locations as points
sewer lines
parcel polygons
Street name annotation

3. Feature Classes
Annotation: Text

4. Data File Formats and ArcGIS
Shapefile - legacy ESRI (ArcView 3.x)
Coverage - legacy ESRI (ArcInfo 7.x)
Geodatabase - most recent (ArcGIS 8.x onwards)
Layer
Type of data format (A Data Format is an implementation of a Data Structure. Examples of a data format include 'coverages', 'shapefiles' and 'grids')
graphic (location and shape data)
Tabular (text, numbers, or other data)
Source:

6. Shapefile (.shp) Each shapefile corresponds to a feature class
A complete shapefile comprises of at least 3 files with the same prefix name( *.shp, *.shx and *.dbf) (should be saved in a same folder)
*.shp = shapefile, *.shx = header and *.dbf = associated database file
Additionally, you may have a *.prj = Projection file, a *.lyr =layer, and other index files.
All these files must be saved in the same workspace.
Contains a single feature type.
Attribute information (stored in dBASE tables)
The linkage of geometric files to separate attribute tables is common to shapefiles and coverages and is called a georelational data model by ESRI.

7. ArcInfo Coverages
A coverage is a collection of files in a subdirectory
Contains multiple geographic feature types
Folder that contains all of these feature classes is the actual coverage
Two folders within a workspace (one with the name of the coverage and another named ‘info’)
These files contain both the graphic and tabular data
Each geographical feature type corresponds to a feature class
An ArcInfo coverage does not have an individual file extension.
Each of the 2 folders contain multiple files. One with coverage name has various .adf files and info folder has .dat and .nit for all the coverages and grids in the workspace.
The best way to manage (copy, move, delete, rename) ArcInfo coverages is with ArcCatalog or ArcInfo Workstation.
Similar description with ArcInfo Grid.

8. ArcInfo Coverages
Icons and hierarchy.

9. Geodatabase (.mdb)
Primary mechanism used to organize and use geographic information in ArcGIS
Geodatabase is a collection of geographic datasets of various types (vector, raster, and tabular data)
Can be created, accessed, managed through standard menus and ArcCatalog, ArcToolbox and ArcMap
object-relational database approach for storing spatial data.
A geodatabase is a "container" for holding datasets, tying together the spatial features with attributes.
With shapefiles, each file can only handle one type of feature. A geodatabase can store multiple feature classes or type of features within one file (held in a common file system folder)

10. Geodatabase

11. Layer File (.lyr) Readable directly by ArcGIS
Does not contain actual geographic data
Specifications for the presentation of other datasets
color
label properties (font, color, placements, etc.)
Such presentation properties are usually time consuming to create, so a .lyr file allows these settings to be saved and shared. In order to use a .lyr file, you must also have a separate data file with the same prefix name saved in the same file space.

12. Icons and hierarchy
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