Writing LAS files

Any LASFile object can be written to a new LAS file using the lasio.LASFile.write() method.

Converting between v1.2 and v2.0

Take this sample LAS 2.0 file:

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~VERSION INFORMATION
 VERS.                          2.0 :   CWLS LOG ASCII STANDARD -VERSION 2.0
 WRAP.                          NO  :   ONE LINE PER DEPTH STEP
~WELL INFORMATION
#MNEM.UNIT              DATA                       DESCRIPTION
#----- -----            ----------               -------------------------
STRT    .M              1670.0000                :START DEPTH
STOP    .M              1660.0000                :STOP DEPTH
STEP    .M              -0.1250                  :STEP
NULL    .               -999.25                  :NULL VALUE
COMP    .       ANY OIL COMPANY INC.             :COMPANY
WELL    .       AAAAA_2            :WELL
FLD     .       WILDCAT                          :FIELD
LOC     .       12-34-12-34W5M                   :LOCATION
PROV    .       ALBERTA                          :PROVINCE
SRVC    .       ANY LOGGING COMPANY INC.         :SERVICE COMPANY
DATE    .       13-DEC-86                        :LOG DATE
UWI     .       100123401234W500                 :UNIQUE WELL ID
~CURVE INFORMATION
#MNEM.UNIT              API CODES                   CURVE DESCRIPTION
#------------------     ------------              -------------------------
 DEPT   .M                                       :  1  DEPTH
 DT     .US/M           60 520 32 00             :  2  SONIC TRANSIT TIME
 RHOB   .K/M3           45 350 01 00             :  3  BULK DENSITY
 NPHI   .V/V            42 890 00 00             :  4  NEUTRON POROSITY
 SFLU   .OHMM           07 220 04 00             :  5  SHALLOW RESISTIVITY
 SFLA   .OHMM           07 222 01 00             :  6  SHALLOW RESISTIVITY
 ILM    .OHMM           07 120 44 00             :  7  MEDIUM RESISTIVITY
 ILD    .OHMM           07 120 46 00             :  8  DEEP RESISTIVITY
~PARAMETER INFORMATION
#MNEM.UNIT              VALUE             DESCRIPTION
#--------------     ----------------      -----------------------------------------------
 MUD    .               GEL CHEM        :   MUD TYPE
 BHT    .DEGC           35.5000         :   BOTTOM HOLE TEMPERATURE
 BS     .MM             200.0000        :   BIT SIZE
 FD     .K/M3           1000.0000       :   FLUID DENSITY
 MATR   .               SAND            :   NEUTRON MATRIX
 MDEN   .               2710.0000       :   LOGGING MATRIX DENSITY
 RMF    .OHMM           0.2160          :   MUD FILTRATE RESISTIVITY
 DFD    .K/M3           1525.0000       :   DRILL FLUID DENSITY
~OTHER
     Note: The logging tools became stuck at 625 metres causing the data
     between 625 metres and 615 metres to be invalid.
~A  DEPTH     DT    RHOB        NPHI   SFLU    SFLA      ILM      ILD
1670.000   123.450 2550.000    0.450  123.450  123.450  110.200  105.600
1669.875   123.450 2550.000    0.450  123.450  123.450  110.200  105.600
1669.750   123.450 2550.000    0.450  123.450  123.450  110.200  105.600

And we can use lasio to convert it to LAS 1.2:

>>> las = lasio.examples.open("2.0/sample_2.0.las")
>>> las.write('example-as-v1.2.las', version=1.2)

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~Version ---------------------------------------------------
VERS. 1.2 : CWLS LOG ASCII STANDARD - VERSION 1.2
WRAP.  NO : ONE LINE PER DEPTH STEP
~Well ------------------------------------------------------
STRT.M         1670.0 : START DEPTH
STOP.M        1669.75 : STOP DEPTH
STEP.M         -0.125 : STEP
NULL.         -999.25 : NULL VALUE
COMP.         COMPANY : ANY OIL COMPANY INC.
WELL.            WELL : AAAAA_2
FLD .           FIELD : WILDCAT
LOC .        LOCATION : 12-34-12-34W5M
PROV.        PROVINCE : ALBERTA
SRVC. SERVICE COMPANY : ANY LOGGING COMPANY INC.
DATE.        LOG DATE : 13-DEC-86
UWI .  UNIQUE WELL ID : 100123401234W500
~Curves ----------------------------------------------------
DEPT.M                 : 1  DEPTH
DT  .US/M 60 520 32 00 : 2  SONIC TRANSIT TIME
RHOB.K/M3 45 350 01 00 : 3  BULK DENSITY
NPHI.V/V  42 890 00 00 : 4  NEUTRON POROSITY
SFLU.OHMM 07 220 04 00 : 5  SHALLOW RESISTIVITY
SFLA.OHMM 07 222 01 00 : 6  SHALLOW RESISTIVITY
ILM .OHMM 07 120 44 00 : 7  MEDIUM RESISTIVITY
ILD .OHMM 07 120 46 00 : 8  DEEP RESISTIVITY
~Params ----------------------------------------------------
MUD .   GEL CHEM : MUD TYPE
BHT .DEGC   35.5 : BOTTOM HOLE TEMPERATURE
BS  .MM    200.0 : BIT SIZE
FD  .K/M3 1000.0 : FLUID DENSITY
MATR.       SAND : NEUTRON MATRIX
MDEN.     2710.0 : LOGGING MATRIX DENSITY
RMF .OHMM  0.216 : MUD FILTRATE RESISTIVITY
DFD .K/M3 1525.0 : DRILL FLUID DENSITY
~Other -----------------------------------------------------
Note: The logging tools became stuck at 625 metres causing the data
between 625 metres and 615 metres to be invalid.
~ASCII -----------------------------------------------------
       1670     123.45       2550       0.45     123.45     123.45      110.2      105.6
     1669.9     123.45       2550       0.45     123.45     123.45      110.2      105.6
     1669.8     123.45       2550       0.45     123.45     123.45      110.2      105.6

Converting between wrapped/unwrapped

Here is an example using this file to convert a wrapped data section to unwrapped.

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~Version Information
 VERS.                1.20:   CWLS log ASCII Standard -VERSION 1.20
 WRAP.                 YES:   Multiple lines per depth step
~Well Information
#MNEM.UNIT       Data Type    Information
#---------    -------------   ------------------------------
 STRT.M            910.000:
 STOP.M            901.000:
 STEP.M            -0.1250:
 NULL.           -999.2500:   Null value
 COMP.             COMPANY:   ANY OIL COMPANY INC.
 WELL.                WELL:   ANY ET AL XX-XX-XX-XX
 FLD .               FIELD:   WILDCAT
 LOC .            LOCATION:   XX-XX-XX-XXW3M
 PROV.            PROVINCE:   SASKATCHEWAN
 SRVC.     SERVICE COMPANY:   ANY LOGGING COMPANY INC.
 SON .     SERVICE ORDER :   142085
 DATE.            LOG DATE:   13-DEC-86
 UWI .      UNIQUE WELL ID:
~Curve Information
#MNEM.UNIT      API CODE      Curve Description
#---------    -------------   ------------------------------
 DEPT.M                       :    Depth
 DT  .US/M                    :  1 Sonic Travel Time
 RHOB.K/M                     :  2 Density-Bulk Density
 NPHI.V/V                     :  3 Porosity -Neutron
 RX0 .OHMM                    :  4 Resistivity -Rxo
 RESS.OHMM                    :  5 Resistivity -Shallow
 RESM.OHMM                    :  6 Resistivity -Medium
 RESD.OHMM                    :  7 Resistivity -Deep
 SP  .MV                      :  8 Spon. Potential
 GR  .GAPI                    :  9 Gamma Ray
 CALI.MM                      : 10 Caliper
 DRHO.K/M3                    : 11 Delta-Rho
 EATT.DBM                     : 12 EPT Attenuation
 TPL .NS/M                    : 13 TP -EPT
 PEF .                        : 14 PhotoElectric Factor
 FFI .V/V                     : 15 Porosity -NML FFI
 DCAL.MM                      : 16 Caliper-Differential
 RHGF.K/M3                    : 17 Density-Formation
 RHGA.K/M3                    : 18 Density-Apparent
 SPBL.MV                      : 19 Baselined SP
 GRC .GAPI                    : 20 Gamma Ray BHC
 PHIA.V/V                     : 21 Porosity -Apparent
 PHID.V/V                     : 22 Porosity -Density
 PHIE.V/V                     : 23 Porosity -Effective
 PHIN.V/V                     : 24 Porosity -Neut BHC
 PHIC.V/V                     : 25 Porosity -Total HCC
 R0  .OHMM                    : 26 Ro
 RWA .OHMM                    : 27 Rfa
 SW   .                       : 28 Sw -Effective
 MSI .                        : 29 Sh Idx -Min
 BVW .                        : 30 BVW
 FGAS.                        : 31 Flag -Gas Index
 PIDX.                        : 32 Prod Idx
 FBH .                        : 33 Flag -Bad Hole
 FHCC.                        : 34 Flag -HC Correction
 LSWB.                        : 35 Flag -Limit SWB
~A Log data section
910.000000
  -999.2500  2692.7075     0.3140    19.4086    19.4086    13.1709    12.2681
    -1.5010    96.5306   204.7177    30.5822  -999.2500  -999.2500     3.2515
  -999.2500     4.7177  3025.0264  3025.0264    -1.5010    93.1378     0.1641
     0.0101     0.1641     0.3140     0.1641    11.1397     0.3304     0.9529
     0.0000     0.1564     0.0000    11.1397     0.0000     0.0000     0.0000
909.875000
  -999.2500  2712.6460     0.2886    23.3987    23.3987    13.6129    12.4744
    -1.4720    90.2803   203.1093    18.7566  -999.2500  -999.2500     3.7058
  -999.2500     3.1093  3004.6050  3004.6050    -1.4720    86.9078     0.1456
    -0.0015     0.1456     0.2886     0.1456    14.1428     0.2646     1.0000
     0.0000     0.1456     0.0000    14.1428     0.0000     0.0000     0.0000
909.750000
  -999.2500  2692.8137     0.2730    22.5909    22.5909    13.6821    12.6146
    -1.4804    89.8492   201.9287     3.1551  -999.2500  -999.2500     4.3124
  -999.2500     1.9287  2976.4451  2976.4451    -1.4804    86.3465     0.1435
     0.0101     0.1435     0.2730     0.1435    14.5674     0.2598     1.0000
     0.0000     0.1435     0.0000    14.5674     0.0000     0.0000     0.0000
909.625000
  -999.2500  2644.3650     0.2765    18.4831    18.4831    13.4159    12.6900
    -1.5010    93.3999   201.5826    -6.5861  -999.2500  -999.2500     4.3822
  -999.2500     1.5826  2955.3528  2955.3528    -1.5010    89.7142     0.1590
     0.0384     0.1590     0.2765     0.1590    11.8600     0.3210     0.9667
     0.0000     0.1538     0.0000    11.8600     0.0000     0.0000     0.0000
909.500000
  -999.2500  2586.2822     0.2996    13.9187    13.9187    12.9195    12.7016
    -1.4916    98.1214   201.7126    -4.5574  -999.2500  -999.2500     3.5967
  -999.2500     1.7126  2953.5940  2953.5940    -1.4916    94.2670     0.1880
     0.0723     0.1880     0.2996     0.1880     8.4863     0.4490     0.8174
     0.0000     0.1537     0.0000     8.4863     0.0000     0.0000     0.0000

We will change the wrap by adjusting the relevant header section in the LASFile header:

>>> las.version
[HeaderItem(mnemonic="VERS", unit="", value="1.2", descr="CWLS log ASCII Standa"),
 HeaderItem(mnemonic="WRAP", unit="", value="YES", descr="Multiple lines per de")]

>>> las.version.WRAP = 'NO'
>>> las.version.WRAP
HeaderItem(mnemonic="WRAP", unit="", value="NO", descr="Multiple lines per dep")
>>> las.write('example-unwrapped.las')
WARNING:lasio.writer:[v1.2] line #58 has 396 chars (>256)
WARNING:lasio.writer:[v1.2] line #59 has 396 chars (>256)
WARNING:lasio.writer:[v1.2] line #60 has 396 chars (>256)
WARNING:lasio.writer:[v1.2] line #61 has 396 chars (>256)
WARNING:lasio.writer:[v1.2] line #62 has 396 chars (>256)

We get warnings because the LAS 1.2 standard doesn’t allow writing lines longer than 256 characters. lasio provides the warning but still produces the long lines:

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~Version ---------------------------------------------------
VERS. 1.2 : CWLS LOG ASCII STANDARD - VERSION 1.2
WRAP.  NO : Multiple lines per depth step
~Well ------------------------------------------------------
STRT.M          910.0 :
STOP.M          909.5 :
STEP.M         -0.125 :
NULL.         -999.25 : Null value
COMP.         COMPANY : ANY OIL COMPANY INC.
WELL.            WELL : ANY ET AL XX-XX-XX-XX
FLD .           FIELD : WILDCAT
LOC .        LOCATION : XX-XX-XX-XXW3M
PROV.        PROVINCE : SASKATCHEWAN
SRVC. SERVICE COMPANY : ANY LOGGING COMPANY INC.
SON .   SERVICE ORDER : 142085
DATE.        LOG DATE : 13-DEC-86
UWI .  UNIQUE WELL ID :
~Curves ----------------------------------------------------
DEPT.M     : Depth
DT  .US/M  : 1 Sonic Travel Time
RHOB.K/M   : 2 Density-Bulk Density
NPHI.V/V   : 3 Porosity -Neutron
RX0 .OHMM  : 4 Resistivity -Rxo
RESS.OHMM  : 5 Resistivity -Shallow
RESM.OHMM  : 6 Resistivity -Medium
RESD.OHMM  : 7 Resistivity -Deep
SP  .MV    : 8 Spon. Potential
GR  .GAPI  : 9 Gamma Ray
CALI.MM    : 10 Caliper
DRHO.K/M3  : 11 Delta-Rho
EATT.DBM   : 12 EPT Attenuation
TPL .NS/M  : 13 TP -EPT
PEF .      : 14 PhotoElectric Factor
FFI .V/V   : 15 Porosity -NML FFI
DCAL.MM    : 16 Caliper-Differential
RHGF.K/M3  : 17 Density-Formation
RHGA.K/M3  : 18 Density-Apparent
SPBL.MV    : 19 Baselined SP
GRC .GAPI  : 20 Gamma Ray BHC
PHIA.V/V   : 21 Porosity -Apparent
PHID.V/V   : 22 Porosity -Density
PHIE.V/V   : 23 Porosity -Effective
PHIN.V/V   : 24 Porosity -Neut BHC
PHIC.V/V   : 25 Porosity -Total HCC
R0  .OHMM  : 26 Ro
RWA .OHMM  : 27 Rfa
SW  .      : 28 Sw -Effective
MSI .      : 29 Sh Idx -Min
BVW .      : 30 BVW
FGAS.      : 31 Flag -Gas Index
PIDX.      : 32 Prod Idx
FBH .      : 33 Flag -Bad Hole
FHCC.      : 34 Flag -HC Correction
LSWB.      : 35 Flag -Limit SWB
~Params ----------------------------------------------------
~Other -----------------------------------------------------
~ASCII -----------------------------------------------------
        910    -999.25     2692.7      0.314     19.409     19.409     13.171     12.268     -1.501     96.531     204.72     30.582    -999.25    -999.25     3.2515    -999.25     4.7177       3025       3025     -1.501     93.138     0.1641     0.0101     0.1641      0.314     0.1641      11.14     0.3304     0.9529          0     0.1564          0      11.14          0          0          0
     909.88    -999.25     2712.6     0.2886     23.399     23.399     13.613     12.474     -1.472      90.28     203.11     18.757    -999.25    -999.25     3.7058    -999.25     3.1093     3004.6     3004.6     -1.472     86.908     0.1456    -0.0015     0.1456     0.2886     0.1456     14.143     0.2646          1          0     0.1456          0     14.143          0          0          0
     909.75    -999.25     2692.8      0.273     22.591     22.591     13.682     12.615    -1.4804     89.849     201.93     3.1551    -999.25    -999.25     4.3124    -999.25     1.9287     2976.4     2976.4    -1.4804     86.347     0.1435     0.0101     0.1435      0.273     0.1435     14.567     0.2598          1          0     0.1435          0     14.567          0          0          0
     909.62    -999.25     2644.4     0.2765     18.483     18.483     13.416      12.69     -1.501       93.4     201.58    -6.5861    -999.25    -999.25     4.3822    -999.25     1.5826     2955.4     2955.4     -1.501     89.714      0.159     0.0384      0.159     0.2765      0.159      11.86      0.321     0.9667          0     0.1538          0      11.86          0          0          0
      909.5    -999.25     2586.3     0.2996     13.919     13.919     12.919     12.702    -1.4916     98.121     201.71    -4.5574    -999.25    -999.25     3.5967    -999.25     1.7126     2953.6     2953.6    -1.4916     94.267      0.188     0.0723      0.188     0.2996      0.188     8.4863      0.449     0.8174          0     0.1537          0     8.4863          0          0          0

If we decide to write the file in LAS 2.0 format, the warnings will go away:

>>> las.write('example-version-2.0.las', version=2.0)

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~Version ---------------------------------------------------
VERS. 2.0 : CWLS log ASCII Standard -VERSION 2.0
WRAP.  NO : Multiple lines per depth step
~Well ------------------------------------------------------
STRT.M                   910.0 :
STOP.M                   909.5 :
STEP.M                  -0.125 :
NULL.                  -999.25 : Null value
COMP.     ANY OIL COMPANY INC. : COMPANY
WELL.    ANY ET AL XX-XX-XX-XX : WELL
FLD .                  WILDCAT : FIELD
LOC .           XX-XX-XX-XXW3M : LOCATION
PROV.             SASKATCHEWAN : PROVINCE
SRVC. ANY LOGGING COMPANY INC. : SERVICE COMPANY
SON .                   142085 : SERVICE ORDER
DATE.                13-DEC-86 : LOG DATE
UWI .                          : UNIQUE WELL ID
~Curves ----------------------------------------------------
DEPT.M     : Depth
DT  .US/M  : 1 Sonic Travel Time
RHOB.K/M   : 2 Density-Bulk Density
NPHI.V/V   : 3 Porosity -Neutron
RX0 .OHMM  : 4 Resistivity -Rxo
RESS.OHMM  : 5 Resistivity -Shallow
RESM.OHMM  : 6 Resistivity -Medium
RESD.OHMM  : 7 Resistivity -Deep
SP  .MV    : 8 Spon. Potential
GR  .GAPI  : 9 Gamma Ray
CALI.MM    : 10 Caliper
DRHO.K/M3  : 11 Delta-Rho
EATT.DBM   : 12 EPT Attenuation
TPL .NS/M  : 13 TP -EPT
PEF .      : 14 PhotoElectric Factor
FFI .V/V   : 15 Porosity -NML FFI
DCAL.MM    : 16 Caliper-Differential
RHGF.K/M3  : 17 Density-Formation
RHGA.K/M3  : 18 Density-Apparent
SPBL.MV    : 19 Baselined SP
GRC .GAPI  : 20 Gamma Ray BHC
PHIA.V/V   : 21 Porosity -Apparent
PHID.V/V   : 22 Porosity -Density
PHIE.V/V   : 23 Porosity -Effective
PHIN.V/V   : 24 Porosity -Neut BHC
PHIC.V/V   : 25 Porosity -Total HCC
R0  .OHMM  : 26 Ro
RWA .OHMM  : 27 Rfa
SW  .      : 28 Sw -Effective
MSI .      : 29 Sh Idx -Min
BVW .      : 30 BVW
FGAS.      : 31 Flag -Gas Index
PIDX.      : 32 Prod Idx
FBH .      : 33 Flag -Bad Hole
FHCC.      : 34 Flag -HC Correction
LSWB.      : 35 Flag -Limit SWB
~Params ----------------------------------------------------
~Other -----------------------------------------------------
~ASCII -----------------------------------------------------
        910    -999.25     2692.7      0.314     19.409     19.409     13.171     12.268     -1.501     96.531     204.72     30.582    -999.25    -999.25     3.2515    -999.25     4.7177       3025       3025     -1.501     93.138     0.1641     0.0101     0.1641      0.314     0.1641      11.14     0.3304     0.9529          0     0.1564          0      11.14          0          0          0
     909.88    -999.25     2712.6     0.2886     23.399     23.399     13.613     12.474     -1.472      90.28     203.11     18.757    -999.25    -999.25     3.7058    -999.25     3.1093     3004.6     3004.6     -1.472     86.908     0.1456    -0.0015     0.1456     0.2886     0.1456     14.143     0.2646          1          0     0.1456          0     14.143          0          0          0
     909.75    -999.25     2692.8      0.273     22.591     22.591     13.682     12.615    -1.4804     89.849     201.93     3.1551    -999.25    -999.25     4.3124    -999.25     1.9287     2976.4     2976.4    -1.4804     86.347     0.1435     0.0101     0.1435      0.273     0.1435     14.567     0.2598          1          0     0.1435          0     14.567          0          0          0
     909.62    -999.25     2644.4     0.2765     18.483     18.483     13.416      12.69     -1.501       93.4     201.58    -6.5861    -999.25    -999.25     4.3822    -999.25     1.5826     2955.4     2955.4     -1.501     89.714      0.159     0.0384      0.159     0.2765      0.159      11.86      0.321     0.9667          0     0.1538          0      11.86          0          0          0
      909.5    -999.25     2586.3     0.2996     13.919     13.919     12.919     12.702    -1.4916     98.121     201.71    -4.5574    -999.25    -999.25     3.5967    -999.25     1.7126     2953.6     2953.6    -1.4916     94.267      0.188     0.0723      0.188     0.2996      0.188     8.4863      0.449     0.8174          0     0.1537          0     8.4863          0          0          0

Formatting data section columns

The keyword parameters that control the column spacing in the data section are, the left-hand spacer, lhs_spacer, and the in-between column spacer, spacer. They are both set to one space by default.

Use the len_numeric_field parameter to configure the padding within the numeric data fields.

The following examples will use lasio/tests/examples/2.0/sample_2.0.las. It’s data section looks like this:

~A  DEPTH     DT    RHOB        NPHI   SFLU    SFLA      ILM      ILD
1670.000   123.450 2550.000    0.450  123.450  123.450  110.200  105.600
1669.875   123.450 2550.000    0.450  123.450  123.450  110.200  105.600
1669.750   123.450 2550.000    0.450  123.450  123.450  110.200  105.600

Default data section formatting

If this file is read in and then written, the data section is formatted like this by default:

import lasio.examples
from lasio.reader import StringIO

las = lasio.examples.open("2.0/sample_2.0.las")
s = StringIO()

las.write(s)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
 1670.00000  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000
 1669.87500  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000
 1669.75000  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000

The default settings are:

  • len_numeric_field defaults to 10 characters

    • 5 digits to the right of the decimal

    • 1 character for the decimal

    • 4 digits for the number to the left of the decimal

      • if there are less than 4 digits, the field is padded with blank spaces
      • if there are more than 4 digits, the field is expanded to include all the digits

  • lhs_spacer defaults to 1 space. So the data is indented by one space.

  • spacer defaults to 1 space. So data columns will have one space dividing them

    • if a number is padded with blanks there will be more spaces seen for that number’s field

Examples: len_numeric_field

Turn off data column left-padding, set len_numeric_field to -1

This removes the padding of the numeric fields and leaves the lhs_spacer and spacer defaults of one space columns.

remove_padding=-1
las.write(s, len_numeric_field=remove_padding)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
 1670.00000 123.45000 2550.00000 0.45000 123.45000 123.45000 110.20000 105.60000
 1669.87500 123.45000 2550.00000 0.45000 123.45000 123.45000 110.20000 105.60000
 1669.75000 123.45000 2550.00000 0.45000 123.45000 123.45000 110.20000 105.60000

Set column width to less than the default: > 0 & < 10

Note in this example that only column 4 is 8 characters wide the other columns are 9 or more characters and expand to fit all their characters.

col_width = 8
las.write(s, len_numeric_field=col_width)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
 1670.00000 123.45000 2550.00000  0.45000 123.45000 123.45000 110.20000 105.60000
 1669.87500 123.45000 2550.00000  0.45000 123.45000 123.45000 110.20000 105.60000
 1669.75000 123.45000 2550.00000  0.45000 123.45000 123.45000 110.20000 105.60000

Set column width to more than the default: > 10

In this example all the columns are padded with space to make them wider. The lhs_spacer, left hand spacer, is still one space wide. The additional space on the left hand side is from the padding of the first data column to the requested col_width of 12 characters.

col_width = 12
las.write(s, len_numeric_field=col_width)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
   1670.00000    123.45000   2550.00000      0.45000    123.45000    123.45000    110.20000    105.60000
   1669.87500    123.45000   2550.00000      0.45000    123.45000    123.45000    110.20000    105.60000
   1669.75000    123.45000   2550.00000      0.45000    123.45000    123.45000    110.20000    105.60000

Examples: lhs_spacer

Remove the left most space, set lhs_spacer to an empty string

The output here removes the default 1 space column from the left hand side. Otherwise, it is the same as the initial default example.

empty_space = ""
las.write(s, lhs_spacer=empty_space)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
1670.00000  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000
1669.87500  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000
1669.75000  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000

Increase the left hand space, set lhs_spacer to a string with more spaces

In this example, there are 3 columns of space at the left hand side.

three_spaces = "   "
las.write(s, lhs_spacer=three_spaces)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
   1670.00000  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000
   1669.87500  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000
   1669.75000  123.45000 2550.00000    0.45000  123.45000  123.45000  110.20000  105.60000

Examples: spacer

Increase the space between columns, set spacer to as string with more spaces

In this example, there are 3 columns of space separating the data columns from each other. In addition some of the columns have more space due to space-padding of their digits to the right of the decimal.

Note that the left hand side only has the 1 space, because it is not in between the columns and is set by the default lhs_spacer setting of one space.

three_spaces = "   "
las.write(s, spacer=three_spaces)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
 1670.00000    123.45000   2550.00000      0.45000    123.45000    123.45000    110.20000    105.60000
 1669.87500    123.45000   2550.00000      0.45000    123.45000    123.45000    110.20000    105.60000
 1669.75000    123.45000   2550.00000      0.45000    123.45000    123.45000    110.20000    105.60000

Use a different character as the spacer character

This example demonstrates using a comma as the column separator. This outputs a set of comma separated data values.

comma_spacer = ","
las.write(s, spacer=comma_spacer)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
 1670.00000, 123.45000,2550.00000,   0.45000, 123.45000, 123.45000, 110.20000, 105.60000
 1669.87500, 123.45000,2550.00000,   0.45000, 123.45000, 123.45000, 110.20000, 105.60000
 1669.75000, 123.45000,2550.00000,   0.45000, 123.45000, 123.45000, 110.20000, 105.60000

Examples: a combined example

This example shows that these options can be combined to produce a variety of output formats. Here the data section is output as a tight comma separated data set.

empty_lhs_spacer = ""
comma_spacer = ","
no_padding = -1
las.write(s, lhs_spacer=empty_lhs_spacer, spacer=comma_spacer, len_numeric_field=no_padding)
s.seek(1665)
print(s.read())

~ASCII -----------------------------------------------------
1670.00000,123.45000,2550.00000,0.45000,123.45000,123.45000,110.20000,105.60000
1669.87500,123.45000,2550.00000,0.45000,123.45000,123.45000,110.20000,105.60000
1669.75000,123.45000,2550.00000,0.45000,123.45000,123.45000,110.20000,105.60000