ArcGIS data is organized in workspace folders and geodatabases

Workspace folders and geodatabases provide the primary containers to store and manage geographic information for ArcGIS. Workspace folders are simply file folders on disk that hold numerous file and personal geodatabases, file-based datasets, and a series of ArcGIS documents.

One of the key workspace folders in ArcMap is each map's home folder, which is the location used by default to store your map document, save results, and create new datasets.

Workspace folders can contain external datasets in many file formats as well as references to geodatabases. For example, you can work with file geodatabases, connect to ArcSDE geodatabases, and work with folders containing numerous data files—such as Esri shapefiles and coverages, JPEG images, DXF CAD files, dBASE tables, Excel spreadsheets, and GML data files.

You organize your datasets and ArcGIS documents into a series of file system folders (often referred to as workspace folders) and in geodatabases. Organizing datasets by workspace folders and in geodatabases is useful because it provides a mechanism to do the following:

• Control access to datasets.
• Provide a transaction framework for updating and sharing datasets.
• Organize, document, and catalog numerous geographic datasets.

Typical contents can include these:

• ArcMap documents (.mxd)
• ArcGlobe documents (.3dd)
• Layer files (.lyr)
• Python scripts (.py)
• Imagery (such as .jpg and .tif files)

ArcGIS applications use a series of documents for saving work created in ArcGIS. These documents define how maps, map elements, map layers, globes, globe elements, and geoprocessing models are managed and used within the software. For example, a map document specifies the set of map layers contained in a map along with the map layout elements and their display properties used to present GIS datasets. Once you create a map document, you can use it simply by double-clicking the document name to open it. This will launch the ArcMap application for the selected map.

Each ArcGIS document is saved as a file in a disk folder.

Some of the commonly used ArcGIS documents found in workspace folders

Document type	File name extension	How it is used	Notes
ArcMap document	.mxd	Double-click to open in ArcMap.	A file containing a map, its layers, display information, and other elements used in ArcMap.
Map package	.mpk	Double-click to open in ArcMap. It is used to share maps and geodatabases with other users and for sharing at ArcGIS Online.	A map document plus a geodatabase for the map's contents. The map document provides all of its specifications, and the geodatabase provides the actual data used in the map.
ArcGlobe document	.3dd	Double-click to open in ArcGlobe.	A file containing a globe, its layers, and 3D display properties for use in ArcGlobe, which is part of the 3D Analyst extension.
ArcScene document	.sxd	Double-click to open in ArcScene.	A file containing a 3D scene, its layers, and 3D properties for use in ArcScene, which is part of the 3D Analyst extension.
Service definition	.sd	Used to publish services with ArcGIS for Server.	Created in ArcMap and saved using the Save a Service Definition window.
Service definition draft	.sddraft	Used to save a draft of a service definition.	Created in ArcMap and saved using the Save a Service Definition window.
Layer file	.lyr	Drag into ArcMap, ArcGlobe, ArcScene, and ArcGIS Explorer.	A layer is a set of rules for displaying and working with datasets in ArcMap and ArcGlobe. Layer definitions include symbol assignments, classifications, labeling rules, and other map use properties.
Layer package	.lpx	Drag into ArcMap, ArcGlobe, ArcScene, and ArcGIS Explorer.	A layer package is a map layer plus its data packaged together. Layer packages are used for sharing both the data and its cartography.
Address Locator file	.loc	Used for geocoding in ArcGIS.	A locator dataset and rules used for geocoding addresses in ArcGIS. Locators are types of geodatabase datasets and can be saved independently of the geodatabase as a disk file for sharing and use.
Geoprocessing toolbox	.tbx	Appears as a toolbox. In ArcGIS for Desktop, it opens a toolbox folder containing geoprocessing models and scripts. It's also used to publish geoprocessing tools to ArcGIS for Server.	Collections of geoprocessing models saved and shared using toolbox files.
Map projection file	.prj	Saved with each dataset as its coordinate system.	Coordinate system and map projection information for a dataset.
Geoprocessing and Python scripts	.py	Used in geoprocessing.	Python (.py) scripts used for geoprocessing in ArcGIS.