Spatial Filter

A Spatial Filter is a region used to include or exclude items based on their positions and geometry relative to the filter.

Spatial Filters can be created from any item on an editable or hittable overlay.

A Spatial Filter can be used once or saved as a named object in a library for future use.

Use the Libraries Control Bar to inspect and amend stored Spatial Filters.

Example

You can use Spatial Filters to display results based on diverse criteria.

For instance, if the Spatial Filter is based on a Polygon item or closed LineString item, it could exclude all items which lie outside it; if it were based on an open LineString item, it could include only those items which intersect with it; or if based on a point item, it could include only those items which contain it.

A Spatial Filter can be used for the following purposes:

  • when applied to an overlay, you can use the Spatial Filter to filter out items from the display. On that particular overlay, only those items will be displayed which pass the Spatial Filter selection tests.
  • when used with Find (Home > Selection) - Filter tab it can be used to limit which items in the current map window are selected.
  • Select the Find items that... pass or fail as required.
  • Click on ... the filter... drop-down box arrow and select the filter to apply to items in the SWD.

Filter types

  • Class Filter - uses each item’s class to decide whether it is included or not. The possible classes are LineString, Point, Polygon etc.
  • Compound Filter - can be used to speed up a Property Filter. You can use a different Property Filter filter for each item class.
  • Feature Filter - uses each item's feature code to decide whether it is included or not.
  • Property Filter - this is the most general type of filter. Using this filter type you could in theory do the job of all the other filter types. But the drawbacks of this filter type are that it is more complicated to use, and will probably operate slower than the other specialised filters.