average ht. difference for 2013-2011 is -2.3 cm with a min/max span of
-20.1 to +22.8 cm.
.qi and .rq files are in /net/gs614wicestream/Volumes/Raid0/gps/truk_surveys/2013
130428_truk_l12_thuleramp_anthtrem_nopark_s3.qi & 130428_truk_l12_thuleramp_anthtrem_nopark_s3.rq