Below is the command line. I had over 5GB of memory free, so I don't think it ran out of memory.
\lastools\bin\lasground -step 1 -i USGS_LPC_CO_Southwest_NRCS_2018_D18_w1009n1687.laz -o eight.laz -vv
Please note that LAStools is not "free" (see
http://lastools.org/LICENSE.txt)
contact '
in...@rapidlasso.de' to clarify licensing terms if needed.
processing file 'USGS_LPC_CO_Southwest_NRCS_2018_D18_w1009n1687.laz'.
horizontal units are meter and vertical units are meter. custom mode.
reading 20458956 points. step: 1 m, sub: 3, bulge: 0.2 m, spike: 1+10 m, offset: 0.05 m, stddev: 10 cm ...
took 16.701 sec. finding initial ground points ...
took 27.712 sec. generating initial ground estimate ...
inserted 5210297 deleted 15650. initial ground TIN has 5194647 points.
took 11.645 sec. refining ground ...
inserted 1536753 deleted 69688. refined ground TIN has 6661712 points.
inserted 29178 deleted 1582. refined ground TIN has 6689308 points.
inserted 3431 deleted 309. refined ground TIN has 6692430 points.
inserted 643 deleted 91. refined ground TIN has 6692982 points.
inserted 159 deleted 24. refined ground TIN has 6693117 points.
inserted 71 deleted 17. refined ground TIN has 6693171 points.
inserted 28 deleted 9. refined ground TIN has 6693190 points.
inserted 21 deleted 4. refined ground TIN has 6693207 points.
inserted 7 deleted 5. refined ground TIN has 6693209 points.
inserted 2 deleted 0. refined ground TIN has 6693211 points.
took 72.115 sec. adding terrain features ...
inserted 7069630 deleted 38416. ground TIN with features has 13724425 points.
took 31.148 sec. integrating points 0.05 above ground ...
ERROR processing file 'USGS_LPC_CO_Southwest_NRCS_2018_D18_w1009n1687.laz'. maybe out of memory?