****************************************************************

  lasindex:

  Creates a *.lax file for a given *.las or *.laz file that
  contains spatial indexing information. When this LAX file is
  present it will be used to speed up access to the relevant
  areas of the LAS/LAZ file whenever a spatial queries of the
  type
    
    -inside_tile ll_x ll_y size
    -inside_circle center_x center_y radius
    -inside_rectangle min_x min_y max_x max_y  (or simply -inside)

  appears in the command line of any LAStools invocation. This
  acceleration is also available to users of the LASlib API. The
  LASreader class has three new functions called

    BOOL inside_tile(F32 ll_x, F32 ll_y, F32 size);
    BOOL inside_circle(F64 center_x, F64 center_y, F64 radius);
    BOOL inside_rectangle(F64 min_x, F64 min_y, F64 max_x, F64 max_y);

  if any of these functions is called the LASreader will only
  return the points that fall inside the specified region and
  use - when available - the spatial indexing information in the
  LAX file created by lasindex.
  
  You can also '-append' the LAX file to the end of the LAZ file.
  
  If some but not all of your LAS or LAZ files are already indexed
  and you do not want to reindex those, then you can add the option
  '-dont_reindex' to the command line which will only process those
  LAS or LAZ files that are not indexed yet.

  For updates check the website or join the LAStools mailing list.

  http://lastools.org/
  http://rapidlasso.com/LAStools
  http://groups.google.com/group/lastools/
  http://twitter.com/lastools/
  http://facebook.com/lastools/
  http://linkedin.com/groups?gid=4408378

  Martin @rapidlasso

****************************************************************

example usage:

>> lasindex -i in.laz

creates a spatial indexing file called 'in.lax' that need to be
in the same folder as the file 'in.laz' to be useful. If you
modify the spatial location, the number of points, or their order
in the file then you need to recreate the LAX file.

>> lasindex -i *.laz

creates a spatial indexing file for all LAZ files *.laz

>> lasindex -i *.laz -append

creates a spatial indexing file for all LAZ files *.laz and appends
them to then end of the LAZ file (not possible when indexing LAS)

>> lasindex -i *.laz -dont_reindex

creates a spatial indexing file for all LAZ files *.laz that do
not yet have a LAX file

****************************************************************

overview of all tool-specific switches:

-v                                   : more info reported in console
-vv                                  : even more info reported in console
-quiet                               : nothing reported in console
-version                             : reports this tool's version number
-gui                                 : start with files loaded into GUI
-cores 4                             : process multiple inputs on 4 cores in parallel
-cpu64                               : start 64 bit lasindex64 instead of 32 bit executable
-dont_reindex                        : skip LAS or LAZ that already have an index
-append                              : append LAX file to LAZ file (not possible for LAS)
-tile_size 50                        : set smallest spatial area indexed to 50 by 50 units
-maximum -30                         : maximum number of intervals per spatial area
-minumum 200000                      : minimum number of points forming one indexed area
-threshold 1500                      : some threshold

****************************************************************

for more info:

D:\software\LAStools\bin> lasindex -h
Filter points based on their coordinates.
  -keep_tile 631000 4834000 1000 (ll_x ll_y size)
  -keep_circle 630250.00 4834750.00 100 (x y radius)
  -keep_xy 630000 4834000 631000 4836000 (min_x min_y max_x max_y)
  -drop_xy 630000 4834000 631000 4836000 (min_x min_y max_x max_y)
  -keep_x 631500.50 631501.00 (min_x max_x)
  -drop_x 631500.50 631501.00 (min_x max_x)
  -drop_x_below 630000.50 (min_x)
  -drop_x_above 630500.50 (max_x)
  -keep_y 4834500.25 4834550.25 (min_y max_y)
  -drop_y 4834500.25 4834550.25 (min_y max_y)
  -drop_y_below 4834500.25 (min_y)
  -drop_y_above 4836000.75 (max_y)
  -keep_z 11.125 130.725 (min_z max_z)
  -drop_z 11.125 130.725 (min_z max_z)
  -drop_z_below 11.125 (min_z)
  -drop_z_above 130.725 (max_z)
  -keep_xyz 620000 4830000 100 621000 4831000 200 (min_x min_y min_z max_x max_y max_z)
  -drop_xyz 620000 4830000 100 621000 4831000 200 (min_x min_y min_z max_x max_y max_z)
Filter points based on their return numbering.
  -keep_first -first_only -drop_first
  -keep_last -last_only -drop_last
  -keep_second_last -drop_second_last
  -keep_first_of_many -keep_last_of_many
  -drop_first_of_many -drop_last_of_many
  -keep_middle -drop_middle
  -keep_return 1 2 3
  -drop_return 3 4
  -keep_single -drop_single
  -keep_double -drop_double
  -keep_triple -drop_triple
  -keep_quadruple -drop_quadruple
  -keep_number_of_returns 5
  -drop_number_of_returns 0
Filter points based on the scanline flags.
  -drop_scan_direction 0
  -keep_scan_direction_change
  -keep_edge_of_flight_line
Filter points based on their intensity.
  -keep_intensity 20 380
  -drop_intensity_below 20
  -drop_intensity_above 380
  -drop_intensity_between 4000 5000
Filter points based on classifications or flags.
  -keep_class 1 3 7
  -drop_class 4 2
  -keep_extended_class 43
  -drop_extended_class 129 135
  -drop_synthetic -keep_synthetic
  -drop_keypoint -keep_keypoint
  -drop_withheld -keep_withheld
  -drop_overlap -keep_overlap
Filter points based on their user data.
  -keep_user_data 1
  -drop_user_data 255
  -keep_user_data_below 50
  -keep_user_data_above 150
  -keep_user_data_between 10 20
  -drop_user_data_below 1
  -drop_user_data_above 100
  -drop_user_data_between 10 40
Filter points based on their point source ID.
  -keep_point_source 3
  -keep_point_source_between 2 6
  -drop_point_source 27
  -drop_point_source_below 6
  -drop_point_source_above 15
  -drop_point_source_between 17 21
Filter points based on their scan angle.
  -keep_scan_angle -15 15
  -drop_abs_scan_angle_above 15
  -drop_abs_scan_angle_below 1
  -drop_scan_angle_below -15
  -drop_scan_angle_above 15
  -drop_scan_angle_between -25 -23
Filter points based on their gps time.
  -keep_gps_time 11.125 130.725
  -drop_gps_time_below 11.125
  -drop_gps_time_above 130.725
  -drop_gps_time_between 22.0 48.0
Filter points based on their RGB/CIR/NIR channels.
  -keep_RGB_red 1 1
  -drop_RGB_red 5000 20000
  -keep_RGB_green 30 100
  -drop_RGB_green 2000 10000
  -keep_RGB_blue 0 0
  -keep_RGB_nir 64 127
  -keep_NDVI 0.2 0.7 -keep_NDVI_from_CIR -0.1 0.5
  -keep_NDVI_intensity_is_NIR 0.4 0.8 -keep_NDVI_green_is_NIR -0.2 0.2
Filter points based on their wavepacket.
  -keep_wavepacket 0
  -drop_wavepacket 3
Filter points based on extra attributes.
  -keep_attribute_above 0 5.0
  -drop_attribute_below 1 1.5
Filter points with simple thinning.
  -keep_every_nth 2 -drop_every_nth 3
  -keep_random_fraction 0.1
  -keep_random_fraction 0.1 4711
  -thin_with_grid 1.0
  -thin_pulses_with_time 0.0001
  -thin_points_with_time 0.000001
Boolean combination of filters.
  -filter_and
Transform coordinates.
  -translate_x -2.5
  -scale_z 0.3048
  -rotate_xy 15.0 620000 4100000 (angle + origin)
  -translate_xyz 0.5 0.5 0
  -translate_then_scale_y -0.5 1.001
  -transform_helmert -199.87,74.79,246.62
  -transform_helmert 598.1,73.7,418.2,0.202,0.045,-2.455,6.7
  -transform_affine 0.9999652,0.903571,171.67,736.26
  -switch_x_y -switch_x_z -switch_y_z
  -clamp_z_below 70.5
  -clamp_z 70.5 72.5
  -copy_attribute_into_z 0
  -add_attribute_to_z 1
  -add_scaled_attribute_to_z 1 -1.2
  -copy_intensity_into_z
  -copy_user_data_into_z
Transform raw xyz integers.
  -translate_raw_z 20
  -translate_raw_xyz 1 1 0
  -translate_raw_xy_at_random 2 2
  -clamp_raw_z 500 800
Transform intensity.
  -set_intensity 0
  -scale_intensity 2.5
  -translate_intensity 50
  -translate_then_scale_intensity 0.5 3.1
  -clamp_intensity 0 255
  -clamp_intensity_above 255
  -map_intensity map_file.txt
  -copy_RGB_into_intensity
  -copy_NIR_into_intensity
  -copy_attribute_into_intensity 0
  -bin_gps_time_into_intensity 0.5
Transform scan_angle.
  -set_scan_angle 0.0
  -scale_scan_angle 1.944445
  -translate_scan_angle -5
  -translate_then_scale_scan_angle -0.5 2.1
Change the return number or return count of points.
  -repair_zero_returns
  -set_return_number 1
  -set_extended_return_number 10
  -change_return_number_from_to 2 1
  -change_extended_return_number_from_to 2 8
  -set_number_of_returns 2
  -set_extended_number_of_returns 15
  -change_number_of_returns_from_to 0 2
  -change_extended_number_of_returns_from_to 8 10
Modify the classification.
  -set_classification 2
  -set_extended_classification 41
  -change_classification_from_to 2 4
  -classify_z_below_as -5.0 7
  -classify_z_above_as 70.0 7
  -classify_z_between_as 2.0 5.0 4
  -classify_intensity_above_as 200 9
  -classify_intensity_below_as 30 11
  -classify_intensity_between_as 500 900 15
  -classify_attribute_below_as 0 -5.0 7
  -classify_attribute_above_as 1 70.0 7
  -classify_attribute_between_as 1 2.0 5.0 4
  -change_extended_classification_from_to 6 46
  -move_ancient_to_extended_classification
Change the flags.
  -set_withheld_flag 0
  -set_synthetic_flag 1
  -set_keypoint_flag 0
  -set_overlap_flag 1
Modify the extended scanner channel.
  -set_scanner_channel 2
  -copy_user_data_into_scanner_channel
Modify the user data.
  -set_user_data 0
  -scale_user_data 1.5
  -change_user_data_from_to 23 26
  -change_user_data_from_to 23 26
  -map_user_data map_file.txt
  -copy_attribute_into_user_data 1
  -add_scaled_attribute_to_user_data 0 10.0
Modify the point source ID.
  -set_point_source 500
  -change_point_source_from_to 1023 1024
  -map_point_source map_file.txt
  -copy_user_data_into_point_source
  -copy_scanner_channel_into_point_source
  -merge_scanner_channel_into_point_source
  -split_scanner_channel_from_point_source
  -bin_Z_into_point_source 200
  -bin_abs_scan_angle_into_point_source 2
  -bin_gps_time_into_point_source 5.0
Transform gps_time.
  -set_gps_time 113556962.005715
  -translate_gps_time 40.50
  -adjusted_to_week
  -week_to_adjusted 1671
Transform RGB/NIR colors.
  -set_RGB 255 0 127
  -set_RGB_of_class 9 0 0 255
  -scale_RGB 2 4 2
  -scale_RGB_down (by 256)
  -scale_RGB_up (by 256)
  -switch_R_G -switch_R_B -switch_B_G
  -copy_R_into_NIR -copy_R_into_intensity
  -copy_G_into_NIR -copy_G_into_intensity
  -copy_B_into_NIR -copy_B_into_intensity
  -copy_intensity_into_NIR
  -switch_RGBI_into_CIR
  -switch_RGB_intensity_into_CIR
Transform attributes in "Extra Bytes".
  -scale_attribute 0 1.5
  -translate_attribute 1 0.2
  -copy_user_data_into_attribute 0
Ignore points based on classifications.
  -ignore_class 7
  -ignore_class 0 1 7 33
Ignore points based on return type.
  -ignore_first -ignore_first_of_many
  -ignore_last -ignore_last_of_many
  -ignore_intermediate
  -ignore_single
Ignore points based on flags.
  -ignore_synthetic -ignore_keypoint
  -ignore_withheld -ignore_overlap
Supported LAS Inputs
  -i lidar.las
  -i lidar.laz
  -i lidar1.las lidar2.las lidar3.las -merged
  -i *.las - merged
  -i flight0??.laz flight1??.laz
  -i terrasolid.bin
  -i esri.shp
  -i nasa.qi
  -i lidar.txt -iparse xyzti -iskip 2 (on-the-fly from ASCII)
  -i lidar.txt -iparse xyzi -itranslate_intensity 1024
  -lof file_list.txt
  -stdin (pipe from stdin)
  -rescale 0.01 0.01 0.001
  -rescale_xy 0.01 0.01
  -rescale_z 0.01
  -reoffset 600000 4000000 0
Fast AOI Queries for LAS/LAZ with spatial indexing LAX files
  -inside min_x min_y max_x max_y
  -inside_tile ll_x ll_y size
  -inside_circle center_x center_y radius
LAStools (by martin@rapidlasso.com) version 190909
usage:
lasindex lidar.las
lasindex *.las
lasindex flight1*.las flight2*.las -verbose
lasindex lidar.las -tile_size 2 -maximum -50
lasindex -h

---------------

if you find bugs let me (martin.isenburg@rapidlasso.com) know.