Thorsden

Hi I've found the answer in using Great Circle calculations and the co-ordinates for tthe ends of the runways included in the data file. Even on short runways using a simple pythagorus triangle solution add in too many errors. The formula in Excel is =ACOS(COS(RADIANS(90-A2)) *COS(RADIANS(90-A3)) +SIN(RADIANS(90-A2)) *SIN(RADIANS(90-A3)) *COS(RADIANS(B2-B3))) *6371 Co-ordinates in A2,B2 and A3,B3 Thanks to BLueMM for the answer. Multiply this result by 1000 to convert to metres in length. This formula gives a 2m error on the published length of Heathrows 3904m runway using the data in the current airport data file. Bob

Hi I hope that I'm posting in an appropriate forum. I'm building a simple web page to display airport information when I input an ICAO code. I can't get the runway lengths out of the world data database. I suspect that it needs calculating by adding together a selection of individual items to produce the whole, but it's beyond me at the moment. Can anyone point me in the right direction of what data I need to extract, filter and add to get this figure? Many thanks Bob