R-tree is a spatial index file used in TatukGIS products to dramatically increase map rendering speed with very large vector layers (such as hundreds of megabytes or more) at relatively closer zoom levels. Upon opening a layer containing vector data with binary representation, such as SHP, TAB, and DGN data, the TatukGIS software tries (if the R-tree feature is enabled) to create an R-Tree (*.rtree) file for future use. In an event R-tree file creation is not possible, such as a read-only situation, the index file is created in-memory. In-memory R-tree files are also created for some vector coverages, such as TGIS_LayerVector, TGIS_LayerMIF, TGIS_LayerDXF, but not for SQL geodatabase layers (because R-tree would be meaningless for SQL layers).
The R-tree index file speeds up most map viewing operations in most situations. For situations not requiring R-tree, the feature can be easily turned off within the layer properties.
To enable r-tree: layer.useRTree := True ; after attaching the layer to the viewer.
To disable r-tree: layer.UseRTtree := False; after attaching the layer to the viewer.
When R-tree is enabled, the optimal enabling level is calculated internally.
In an event the R-tree file becomes corrupted for some reason, the *.rtree file can be safely deleted. Then the index will then be rebuilt automatically when the layer is next opened.