PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2010-12-15 NOTE = "LOLA Software Tools" END_OBJECT = TEXT END README This file describes command-line executable tools for outputting LOLA Reduced Data Record (RDR) files by detector, data type, etc. The individual RDR detached label points to a description of all columns in the LABEL/LOLARDR.FMT file. These tools apply the scale factors in the label and simplify the process of extracting data values for analysis The file HOWTO_USE_LOLA_SOFTWARE.TXT in the DOC/ folder gives a more detailed software description and usage notes. The executable tools may be used to reduce the size of the table output by eliminating instrument noise and non-altimetric measurements. A given detector altimetric spot (1-5) is classified as 'ground' or 'not ground' in several stages. The RDR pipeline processing flags spots with invalid pulse measurements, or altitudes exceeding -10.4 to 12.6 km. If no pulse is detected, flags are set and the detector 1 boresight is geolocated onto the reference sphere to give a continuous ground track. Following product generation the auto-noise editor compares spots in sequence along track and flags spots as 'not ground' if the point-to-point slope exceeds certain limits, or if the number of potential ground spots is less than 10 in any 2-second period of time. The noise editor sets both bit 6 and bit 0 in a flag word (see table below). Manual inspection compares altitudes with values interpolated from a global DEM and may set or clear bit 0 based on a visual assessment. Manual editing recovers sparsely posted values and rejects inconsistent values that escape the automatic editor. Bits 0 and 15 may be set if the value is deemed 'weird' but potentially good. Since more than one review of the data may be performed, the version of edits applied is added as a comment to the detached label. A data user may ignore edit flags and print all values, as in rdr2csv, or reject various combinations of N, M, and W flags: Flag W N M ------ - - - Bit 15 6 0 Test ------ - - - Ground x 0 and 0 Manual only x x 0 Auto only x 0 x ground and weird 1 or both 0 and 0 To generate a profile, for example, rdr2xyz will select only ground values, unless options 'N' or 'M' or 'W' are used, where N selects data that passes the auto-noise editor, M selects data that is manually approved, and W selects data that are considered probably valid, but not definitively so. Options are not case-sensitive and only the first character is used. Programs -------- rdr2table is a swiss-army-knife that outputs multiple columns for any or all detector ids. ID 0 is reserved for the spacecraft, while ID 1-5 in any order will output LOLA heights, with the numbers corresponding to a LOLA receiver. See the program usage message for the various switches that can be turned on. rdr2tab is a slightly slower program with more options to select output and limit the geographical range and observation geometry. It will optionally output UTC Day-of-year date/time, but requires the leapsecond file 'naif0009.tls' to be in the working directory. rdr2xyz outputs 3 columns from a single filename, as binary triples, for one or more detectors as separate output files. This program requires an output file template that sets the geographical limits of the area of interest. For example, rdr2xyz LOLARDR_092002359.DAT hgtdir/LOLARDR_092002359.DAT a f g l will output geopotential height on all 5 detectors flagged as ground over limits specified in 'r2x.prm', if it exists. rdr2xyz without any arguments will give program usage. rdr2csv converts an RDR to a comma-separated-value file. It reads one record of the RDR and outputs all columns in their engineering and scientific values. It uses the SPICE toolkit to extract the Terrestrial Dynamic Time from each record that corresponds to the laser fire, and outputs UTC Calendar date/ time. The output is comma-delimited, ASCII text. A sample label file RDR2CSV.LBL describes the columns. NOTES: In addition to the source, some compiled executables are provided. The MacPPC_OSX_gfortran_bin executables run under MacOS 10.4.11 and 10.5.8 with G4 and G5 processors. In order to read the binary RDR tables on these Bigendian machines, the "Swap" option should be specified. The MacPPC_OSX_Leopard_bin executables run under MacOS 10.5.8 only. The MacIntel_OSX_Leopard_bin executables run on Intel-based MacOS 10.5.8 and 10.6.4 computers. The MacIntel_OSX_Tiger_bin executables run in 32-bit mode on MacOS 10.4.11 and later computers. BUGS: rdr2csv requires the SPICE leapsecond file naif0009.tls in the working directory, and this file may need updating in the future. Contact Information =================== To get additional information about LOLA software, or to report bugs, please contact: Gregory A. Neumann (301) 614-6026 gregory.a.neumann@nasa.gov Kopal Jha kopal.jha@sigmaspace.com NASA Goddard Space Flight Center Mailstop 698.0 Greenbelt, MD 20771