Greetings [note that by default replies go to the poster - not the list]: In JSBSim we are addressing this in our own way (at the moment), programmatically using an STL map (indexed by STL strings) to index conversion factors like this:
convert["M"]["FT"] = 3.2808399; convert["FT"]["M"] = 1.0/convert["M"]["FT"]; convert["M2"]["FT2"] = convert["M"]["FT"]*convert["M"]["FT"]; convert["FT2"]["M2"] = 1.0/convert["M2"]["FT2"]; convert["FT"]["IN"] = 12.0; convert["IN"]["FT"] = 1.0/convert["FT"]["IN"]; convert["LBS"]["KG"] = 0.45359237; convert["KG"]["LBS"] = 1.0/convert["LBS"]["KG"]; convert["SLUG*FT2"]["KG*M2"] = 1.35594; convert["KG*M2"]["SLUG*FT2"] = 1.0/convert["SLUG*FT2"]["KG*M2"]; convert["RAD"]["DEG"] = 360.0/(2.0*3.1415926); convert["DEG"]["RAD"] = 1.0/convert["RAD"]["DEG"]; convert["LBS/FT"]["N/M"] = 14.5939; convert["LBS/FT/SEC"]["N/M/SEC"] = 14.5939; convert["N/M"]["LBS/FT"] = 1.0/convert["LBS/FT"]["N/M"]; convert["N/M/SEC"]["LBS/FT/SEC"] = 1.0/convert["LBS/FT/SEC"]["N/M/SEC"]; convert["M"]["M"] = 1.00; convert["FT"]["FT"] = 1.00; convert["IN"]["IN"] = 1.00; convert["IN3"]["IN3"] = 1.00; convert["DEG"]["DEG"] = 1.00; convert["RAD"]["RAD"] = 1.00; convert["M2"]["M2"] = 1.00; convert["FT2"]["FT2"] = 1.00; convert["KG*M2"]["KG*M2"] = 1.00; convert["SLUG*FT2"]["SLUG*FT2"] = 1.00; convert["KG"]["KG"] = 1.00; convert["LBS"]["LBS"] = 1.00; convert["LBS/FT"]["LBS/FT"] = 1.00; convert["N/M"]["N/M"] = 1.00; convert["LBS/FT/SEC"]["LBS/FT/SEC"] = 1.00; convert["N/M/SEC"]["N/M/SEC"] = 1.00; convert["PSI"]["PSI"] = 1.00; convert["INHG"]["INHG"] = 1.00; convert["HP"]["HP"] = 1.00; Since this is only done at initialization time, CPU usage is not so critical for us. I'd be interested in hearing more about standard unit abbrev.s, though. Jon Berndt
