Optec LIDAR

The Optec LIDAR operated up to 2008 is owned and processed by ULM - see Processing/LIDAR.

It outputs raw files with the name "surveyX.range" (possibly compressed with bzip2 or gzip if I got near them). There may also be a surveyX.pos file (applanix navigation?).

Scanning through 2006 & 2007, it looks like the surveyX.range files have a header of ~16 bytes:

00000000  7a a5 80 07 00 00 00 00  7a a5 80 0d 00 00 02 c8 |z.......z.......|

The .pos files (very limited sample here) seem to start with "$GRP":

/users/rsg/arsf/arsf_data/2006/flight_data/136_WM06_04/lidar/raw-lidar/136-06_Madrid/survey15.pos
00000000  24 47 52 50 04 00 3c 00  64 8e 50 92 be 17 0a 41 |$GRP..<.d.P....A|
/users/rsg/arsf/arsf_data/2006/flight_data/144_WM06_11/lidar/raw-lidar/144_06b_RioTinto/survey6.pos
00000000  24 47 52 50 04 00 3c 00  0a cb 09 46 02 5d 12 41 |$GRP..<....F.].A|
/users/rsg/arsf/arsf_data/2006/flight_data/153_WM06_13/lidar/raw-lidar/153_06a_Rodalquillar/survey24.pos
00000000  24 47 52 50 01 00 84 00  ac d8 c1 9f c1 29 1c 41 |$GRP.........).A|
/users/rsg/arsf/arsf_data/2006/flight_data/157_WM06_07/lidar/raw-lidar/157_06_Toulouse/survey12.pos
00000000  24 47 52 50 04 00 3c 00  78 0f 92 5a 96 ed 09 41 |$GRP..<.x..Z...A|
/users/rsg/arsf/arsf_data/2006/flight_data/158_WM06-09/lidar/raw-lidar/158-06_Sinard/survey13.pos
00000000  24 47 52 50 01 00 84 00  b5 4f b4 2a 84 aa 11 41 |$GRP.....O.*...A|
/users/rsg/arsf/arsf_data/2006/flight_data/184_GB06_09/lidar/raw-lidar/184-06_IOW/survey26.pos
00000000  24 47 52 50 04 00 3c 00  ed 59 55 f6 57 4e fd 40 |$GRP..<..YU.WN.@|

The processed files are typically called "strips/Str_XXX.all" (.bz2) and are plain ASCII, looking like:

  301041.000020   368399.57   90948.05   72.55    30   368399.57 90948.05   72.55    30
  301041.000050   368400.93   90948.22   72.42    51   368400.90 90948.22   72.51    51

The format appears to be:

217755.001130 30563577.97 4513423.12 1293.23 178 30563577.96 4513423.12 1293.28 178
GPS_time (? pulse) ZZeasting [last_pulse] northing [last_pulse] height(m) [last_pulse] intensity [last_pulse] ZZeasting [first_pulse] northing [first_pulse] height(m) [first_pulse] intensity [first_pulse]

where ZZ = UTM zone number

Handy tip for Linux users: strip off the UTM zone numbers with this command:
cat Str123.all | awk '{print $2, $3, $4, $6, $7, $8}' > Str123-stripped.all
or this one, if you prefer sed:
cat Str123.all | sed 's/^\( *[.0-9]* *\)..\([.0-9]* *[.0-9]* *[.0-9]* *[.0-9]* *\)..\([.0-9]* *[.0-9]* *[.0-9]* *[.0-9]*\)/\1\2\3/' > Str123-stripped.all

There's an accompanying header called something like YYJJJ[a-z]_SITENAME_header.txt.

Last modified 8 years ago Last modified on Mar 23, 2009 12:27:04 PM