Hi!Loading by chord in LWMviewer you get the different types of BGL-files (example: AB954180.BGL, FL954180.BGL, HL954180.BGL, HP954180.BGL, PK954180.BGL, RD954180.BGL, RR954180.BGL, ST954180.BGL, UT954180.BGL). What do these files contain? Where can I read about these file-types of BGL?Best RegardsLars

I think these are the different types of terrain data for the sim. FS2002 had a similar scheme, but with different abbreviations. Here's my take at what's what:AB - Airport BackgroundsFL - airport FLatteningHL - Hydrology Lines (shore lines)HP - Hydrology Polygons (lakes/oceans)PK - ParK polygonsRD - RoaD linesRR - RailRoad linesST - STreamsUT - UTility linesThat's my guess. Others may have also posted on this topic.

Thanks for your answer! I found something in the LWMviewer manual too http://www.jimkeir.co.uk/FlightSim/LWMViewer.htmlbut your explanation includes why the acronymes is named as they are and that makes it easier to remember!CheersLars ;-)