Contour Index Lines : Contour lines accompanied by a numerical value indicating elevation. Index contours are usually shown on a map as a thicker line to distinguish them from standard contour lines
Dr. Robert Stacey (compilor), European Glossary of Wildfire Terminology (Covering areas of wildfire environment, fire behaviour, fuel, topography, weather, wildfire suppression operations, safety, incident command, tactics, cartography and map reading, equipment, aerial operations, wildfire preparation, prevention and recovery, prevention and detection, fire investigation and restoration), EUFOFINET (European Forest Fire Networks) Project, Northumberland Fire and Rescue Service, Northumberland UK 2012 (1st Ed.). http://www.fire.uni-freiburg.de/literature/EUFOFIN ET-Fire-Glossary.pdf, (For Fr - Brit) {808}