(t)alinqfit information
sm 9/3/97
alinqfit and talinqfit are Sun/unix programs that are used for processing
laser altimeter elevation data from the NASA/WFF Airborne Topographic Mapper.
alinqfit compares two ranked laser elevation files. Ranking is done
by the rankqfit program. A search radius is specified, then each pair
of laser measurements ( one from the first file and another
from the second file) which fall within the specified radius of one another
are compared. The elevation difference of the pair is written to an
output file.
talinqfit is similar to alinqfit, but uses the output of trankqfit
which carries time information in the last word. talinqfit preserves
this time information.
in the descriptions below, talinqfit may be substituted for alinqfit.
alinqfit is run by typing at the unix prompt:
alinqfit alin.cmd
where alin.cmd is a command file such as:
------- sample command file -----------
filenameA.rq
filenameB.rq
2.5 | search radius
0
0
------ end of command file
The above command file would cause the creation of an output file with
the name (the radius is tacked onto the end):
filenameB.rq.minus.filenameA.rq.alin2.5
OPTIONS:
running the program with the following options will add information
to the output:
alinqfit -b alin.cmd : this includes lat/lon from both input points
alinqfit -r alin.cmd : this includes the distance between points compared
OUTPUT FORMAT:
The output file has a scaled integer format similar to qi or rq files,
including a header. Each data record contains information about point B
(the data point from file B) and point A (the data from file A).
the output file contains data in this order, but the presence of the words
will vary as noted. most of the info is carried over directly from the
input file.
lat of ptB
lon of ptB
elv of ptB
elv difference ptB minus ptA in mm
lat of pt A (only with -b option)
lon of pt A (only with -b option)
distance between ptA and ptB, in mm (only with -r option)
transmit energy of ptA --- (only if present in input fileA)
receive energy of ptA "
scan azimuth of ptA "
pitch of ptA "
roll of ptA "
transmit energy of ptB --- (only if present in input fileB)
receive energy of ptB "
scan azimuth of ptB "
pitch of ptB "
roll of ptB "
time of ptB (HHMMSSmmm) (only present in talinqfit output)
time of ptA (HHMMSSmmm) (only present in talinqfit output)
OTHER NOTES:
alinqfit makes use of information placed into the first line
of the file header by rankqfit. If the files are ranked according
to latitude, then word 3 is set to zero, if they are ranked
according to longitude then word 3 is set to 1. (these values
should be long integer, i.e. 4 bytes)