«  Expression viewer   ::   Contents   ::   Help contents  »

Filter viewer

Filter viewers are used in Style Editor dialog and other areas where selecting the content you wish to work with is important. A formula is used to select content on a feature by feature basis.

This is a powerful technique that can be used for on the fly styling, or directly for data processing.

You can switch between appropriate options using the drop down arrow on the right hand side. Depending on what content you are working with different options will be listed some of which are described below:

Common examples:

Related concepts

Constraint Query Language

Related reference

Style Editor dialog

Transform dialog

Constraint Query Language

This is a plain viewer offering simple constraint query language input.

It does offer dynamic help with auto completion for:

  • Attributes are listed from the feature type you are working with
  • Function are listed, with pop up function reference


A friendly general purpose viewer offering constraint query language input. Provides a list of attributes, operations and values that can be inserted into your filter.


Offers an easy way to enable or disable a rule. This is not a general purpose viewer.

  • Enable: To include all features.

  • Disable: To ignore all features.


This viewer is often used in the Style Editor dialog to toggle a Rule on or off.

«  Expression viewer   ::   Contents   ::   Help contents  »