Geodatabases
What is a Geodatabase in ArcGIS?
Overview
Geodatabases are a term utilised by ArcGIS. They can usefully be contrasted with shapefiles and spatial databases.
Shapefiles
Shapefiles are a longstanding open specification of data interoperability for vector data types.
A shapefile may only contain one vector data type:
- points
- lines
- polygons
Files in a shapefile:
The various files can be distinguished by their extensions:
- shp - shape geometry
- shx - shape index
- dbf - attributes (dBase format)
- prj - projection (crs wkt)
Feature Layer:
A Feature layer is a zipped shapefile collating all the files that make up the “shapefile” itself.
Spatial Database Servers
Spatial databases, such as Postgres with the PostGIS extension, provide their own spatial indexing and spatial functions (e.g. ST_Contains(), ST_Intersects(), etc.)
Geodatabases
Geodatabases are ESRI-specific. They are either server- or file-based systems. They are managed using ArcGIS Catalog.
File-based geodatabases:
The file-based geodatabases can be distinguished by their extensions:
- mdb - Personal Geodatabase - An MS Access RDBMS (deprecated)
- geodatabase - Mobile Geodatabase - An SQLite RDBMS.
- gdb - File Geodatabase - A collection of files in a folder. Can store non-vector datatypes.
Server-based geodatabases:
Enterprise Geodatabases - also known as multi-user geodatabses
ArcGIS acts as an application server, utilising storage in a database server:
- DB2
- Oracle
- PostgreSQL
- SAP HANA
- SQL Server
Further Reading”
ESRI, Shapefiles
— What is a geodatabase?. ArcGIS Pro 3.3, ESRI.
— File geodatabases. ArcGIS Pro 3.3, ESRI.
— Types of geodatabases. ArcGIS Pro 3.3, ESRI.
— Elaine Evans (18 may 2023). It’s Not Personal: A brief history of the geodatabase and why personal geodatabases are not in ArcGIS Pro. ArgGIS Pro, Data Management, ESRI.
— Donald Rees (14 January 2021) Look at Mobile Geodatabases go! (What’s new in Pro 2.7). ArgGIS Pro, Data Management, ESRI.
Wikipedia Shapefile
QED
© Adam Heinz
17 June 2024