Adding database linkages based on Spatial Recognition relies on something that is easy for a human to do, but is harder for a computer. Namely saying “This is inside that”.
This process requires that the base drawing has areas that have been “polygonized” - the outlines of the areas are defined using a single, closed polygon. This process is very common in drawings that are used for Computer Aided Facilities Management (CAFM) systems such as Archibus or Tririga. If the areas are merely defined using lines, arcs and other simple geometry then our Spatial Recognition routines (aka “RL/TL” for “Room Layer/Text Layer”) cannot recognize the areas and will not work.
The user will define two layers or sets of layers that define the layers used for the area polygons (also known as the Room Layer since this facility was first designed to work with CAFM systems, so the areas are rooms) and the layers for the text that define a unique identifier for the area, usually the Room Name. The Spatial Recognition process will then match the unique Text Ids with their corresponding Areas. It processes them in the following order:
1. All text that falls entirely inside a single area polygon - If more than one text is inside the given polygon then the text that is closest to the center of the polygon is used 2. All text that is closest to an area polygon that was not matched in step one - Again "closest wins" any ties
Whereas Spatial Recognition relies on which layers entities are on, Block-based Linkages are based on the name(s) of the blocks, regardless of layer.
The user specifies the name or names of blocks and all such block instances are converted to linkages. The clickable area for the link can be either a circle centered on the midpoint
of the block area or a polygon tracing the block area.
Attribute-based linkages are a specialized case of Block-based linkages. Where in Block-based all block references of a given Block Name are converted to linkages, under Attribute-based
processing, the blocks must also contain an attribute of a given Tag Name that contains a value. The value does not matter, just as long as it is not blank.
Text-based linkages are based on the layer(s) the text is on. All text on the given layer(s) is converted into links.
The clickable area for the link can be either a circle centered on the midpoint of the text or a polygon tracing the text area.