Application Properties

While many configuration and setup options are available through the Web Administration application Settings > Global page, more fundamental (and security minded) changes to how the application operates are made using “Application Properties” defined by:

Java System Properties
Web Application context parameters
System Environmental Variable.

As part of the operating environment GeoServer application properties, unlike settings, cannot be changed at runtime.

Setting Application property

Application properties are determined using the first value obtained from: Java System Properties, Web Application context parameters, or System Environmental Variable.

See also:

Using GEOSERVER_DATA_DIR as an example:

Java System Properties: Supplied to the java virtual machine as part of your application server configuration.
```
-DGEOSERVER_DATA_DIR=/var/lib/geoserver_data
```
- For Tomcat on linux edit setenv.sh to append additional java system properties:
```
# Append system properties
CATALINA_OPTS="${CATALINA_OPTS} -DGEOSERVER_DATA_DIR=/var/lib/geoserver_data"
```
- For Tomcat on windows use Apache Tomcat Properties application, navigating to the Java tab to edit Java Options:
```
-DGEOSERVER_DATA_DIR=C:\ProgramData\GeoServer\data
```
While not commonly used for GEOSERVER_DATA_DIR, this approach is a popular way to enable/disable optional geoserver functionality.

See Set Java startup options for more details.
Web Application context parameter:
- Recommended: Use your application server to configure the GeoServer web application via conf/Catalina/localhost/geoserver.xml file:
```
<Context docBase="geoserver.war">
  <Parameter name="GEOSERVER_DATA_DIR"
             value="/var/opt/geoserver/data" override="false"/>
</Context>
```
  This is the approach documented in our setup instructions for GEOSERVER_DATA_DIR and is recommended.
  
  Note
  
  Tomcat management of application properties as using overide="false" is not the most straight forward to understand. This setting prevents the WEB-INF/web.xml included in the geoserver.war to overide the provided file location.
  
  Other application servers provide a user inteface to manage web application properties and are more intuitive.
- Not recommended: Hand editing the webapps/geoservere/WEB-INF/web.xml file:
```
<context-param>
  <param-name>GEOSERVER_DATA_DIR</param-name>
  <param-value>/var/lib/geoserver_data</param-value>
</context-param>
```
  Note
  
  This file is part of the GeoServer application and will be replaced when updating the application.
  
  As a result this approach is error prone making updates more difficult and is not recommended.
Operating environmental variable:
```
export GEOSERVER_DATA_DIR=/var/lib/geoserver_data
```
This approach can be useful for GEOSERVER_DATA_DIR when running GeoServer in a docker container, traditionally managed with environmental variables.

GeoTools system properties

The GIS library used by GeoTools for working with spatial data has a number of configuration options avaialble as system properties.

Recommended: org.geotools.referencing.forceXY=true

The official EPSG database specifies ordinates following the scientific tradition of most accurate value first. Many computer systems assume that the order should follow easting / northing order (corresponding to x / y pixel order on screen).

This setting is recommended for greater compatibility with a wider range of web services.

Reference: Axis Order

Optional: org.geotools.referencing.operation.order=AreaFirst

When choosing a math transform between coordiante reference systems GeoTools defaults to an AccuracyFirst setting. For greater compatibility with PROJ systems an AreaFirst setting may be used, prioritizing math transforms that covers a larger area.

Reference: Coordinate operations tuning