how to add curve header to output of las.write() with lasio.py

Question

I'm using the python lasio.py library and I must be missing in something in the docs.

Is there a native way to add headers columns in the ~ASCII (~A) section of the output file.

I need to output something like

~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

where I'm actually getting

~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

written to my output file.

I feel like I'm missing something really obvious.

edit: output for file is pretty straight forward:

las.write(outfilename + '.las', fmt='%.3f', version=2)

cheers

Answer 1

To anyone who comes across this issue, here is a workaround. You need to modify the writer.py file in the lasio package. Create a list with curve mnemonics, convert it to np array, stack said array on top of data_arr using np.vstack()

data_arr = las.data    # original code

# adding curve names as headers - insert these 5 lines in writer.py
hdr_list = []
for hdr_item in las.curves:
    hdr_list.append(hdr_item.mnemonic)
hdrs = np.array(hdr_list).reshape(1, -1)
data_arr = np.vstack((hdrs, data_arr))

nrows, ncols = data_arr.shape   # original code

Answer 2

As of the current (June 2022) version of Lasio: v0.30

The Curve headers can be included in the ~ASCII data_header.

Here is the basic syntax example:

las.write(s, mnemonics_header=True, data_section_header="~ASCII")

If the curves in the las document/object are:

~Curve Information -----------------------------------------
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

Then calling las.write(s, mnemonics_header=True, data_section_header="~ASCII") will include the curve headers as the ASCII header: ~ASCII DEPT DT RHOB NPHI SFLU SFLA ILM ILD

Output:

...
~ASCII  DEPT         DT       RHOB       NPHI       SFLU       SFLA        ILM        ILD
 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
...