Filtering Data Controlling data using filters

Filtering Data

A filter is a mechanism for separating a subset of information from the whole data set, such that only the data you wish to load, display or process, is available; the rest is ignored. Being object-based, your Datamine application is not as dependent on filters as earlier versions, but there are still many occasions where filtering is desirable.

Filters operate at several levels:

• Data can be filtered as it is loaded or reloaded in to memory.

• An object (data in memory) can be filtered such that only a part of the object is used in certain commands.

• An object type, individual object or all loaded objects can be filtered such that only part of the data is displayed e.g. in the 3D (any), Plots, Tables or Reports windows.

Filtering Data on Loading

Datamine binary format files can be filtered as they are loaded from the Project Files control bar, using the dialog that opens if the <Ctrl> key is depressed when the loading operation is initiated. All the fields are listed, and the check boxes can be used to select the fields that are to be loaded; clearing a Data Field check box will result in the field not being loaded.

There is a filter entry box, in the Filter group,  where a filter expression may be entered (e.g. GROUP = 1) to load a subset of the data. This also provides access to the Expression Builder dialog which can be used to construct more complex filter expressions. 

Filtering Multiple Objects by Data Type

Once data has been loaded, the various objects can be filtered by object type using the Formatribbon's variousFilterbuttons. These open the Expression Builder dialog which is then used to create, save or retrieve, then apply a filter expression.

Use the Filter All Objects commands to filter multiple objects when: data have already been loaded into memory working with multiple objects of the same object type, which contain a shared user-defined attribute e.g. geological string model and grade control outlines,  with a mineralization zone code (e.g. ZONE=2) an underground mine design consisting of separate string models for development and stoping, with a work area attribute (e.g. LEVEL=127) working with multiple objects of the same object type which can then be filtered using coordinate ranges.

 

Filter Expressions:

The filter expressions which are defined in the Expression Builder dialog are  the mechanism used for filtering data. They are constructed using logical expression syntax. These filter expressions will be accepted after a cursory check of syntax, however, if a filter expression is valid (in that it contains syntax in the correct structure) but is intended for filtering data fields that do not exist in the incoming file, the file will be loaded without filtering. For example, if you elect to filter a wireframe model based on, say, an XP field, but this field does not exist in the loaded file, then the entire contents of the file will be loaded i.e. filtering will not be performed.

	Related Topics
	Logical Expressions Expression Builder Dialog