Issue with generating DSM using las2dem

[Hsin-Ju Li]

Hi,

I have an issue to generate a DSM from a laz, which has been lasclassify. Here is the commend I used: 

wine64 las2dem -i /mypath/-2205000_1564500.laz -spike_free 0.66 -step 1 -use_tile_bb -odir /mypath -otif -no_kml

The laz file can be downloaded here. (I didn't upload here because of the size limitation.)

The same laz can be used to generate DEM but not DSM. I got unusual message in the terminal:

wine: Unhandled page fault on read access to 00000000 at address 0045E32F (thread 0104), starting debugger...
preloader: Warning: failed to reserve range 0000000000010000-0000000000110000
010c:err:environ:init_peb starting L"C:\\windows\\syswow64\\winedbg.exe" in experimental wow64 mode
010c:err:syslink:SYSLINK_SetFont Failed to create link font!
010c:fixme:imm:ImeSetActiveContext (00020048, 1): stub
010c:fixme:imm:ImmReleaseContext (00010054, 00020048): stub
0098:fixme:imm:ImeSetActiveContext (0000000000010026, 0): stub
0098:fixme:imm:ImmReleaseContext (0000000000010020, 0000000000010026): stub
Unhandled exception: page fault on read access to 0x00000000 in segmented 32-bit
 code (0107:0045e32f).
In segmented 32 bit mode.
Register dump:
 CS:0107 SS:0023 DS:0023 ES:0023 FS:010f GS:0023
 EIP:0045e32f ESP:0072ede8 EBP:00000000 EFLAGS:00010206(  R- --  I   - -P- )
 EAX:00000000 EBX:80000002 ECX:0072edf8 EDX:0072ee08
 ESI:755555c0 EDI:0efa5740
Stack dump:
0x0072ede8:  40000000 4076130a 60000000 40808c66
0x0072edf8:  40000000 407612e1 60000000 40808c66
0x0072ee08:  60000000 4076128f 60000000 40808c66
0x0072ee18:  0040220e 00000000 00000000 0efa5740
0x0072ee28:  80000008 755555c0 00401e63 755555c0
0x0072ee38:  0efa5740 3ba4c4bc 0efa5740 0072fef0
0021: sel=010f base=003e2000 limit=00000fff 32-bit rw-
Backtrace:
=>0 0x0107:0x0045e32f in las2dem (+0x5e32f) (0x00000000)
0x0107:0x0045e32f las2dem+0x5e32f: flds 0x0(%eax)
Modules:
Module  Address                 Debug info      Name (20 modules)
PE      00190000-001cf000       Deferred        advapi32
PE      001d0000-001fb000       Deferred        glu32
PE      00400000-0062b000       Export          las2dem
PE      00ff0000-0119e000       Deferred        user32
PE      011a0000-01269000       Deferred        ucrtbase
PE      01270000-012cb000       Deferred        combase
PE      64a80000-64ab9000       Deferred        win32u
PE      65480000-6550a000       Deferred        rpcrt4
PE      65680000-6571f000       Deferred        msvcrt
PE      66080000-6609f000       Deferred        msacm32
PE      66380000-664a1000       Deferred        ole32
PE      66640000-6664c000       Deferred        version
PE      67500000-67519000       Deferred        imm32
PE      6bbc0000-6bbe9000       Deferred        sechost
PE      6da80000-6db00000       Deferred        gdi32
PE      6f240000-6f302000       Deferred        winmm
PE      7a800000-7a926000       Deferred        opengl32
PE      7b000000-7b290000       Deferred        kernelbase
PE      7b600000-7b65a000       Deferred        kernel32
PE      7bc00000-7bc9d000       Deferred        ntdll
Threads:
010c:fixme:thread:get_thread_times not implemented on this platform
process  tid      prio    name (all IDs are in hex)
00000020 start.exe
        00000024    0
00000038 services.exe
        0000003c    0
        00000040    0     wine_rpcrt4_server
        0000004c    0     wine_rpcrt4_io
        00000070    0     wine_rpcrt4_io
        0000009c    0     wine_rpcrt4_io
        000000b4    0     wine_rpcrt4_io
        000000d8    0     wine_rpcrt4_io
00000044 winedevice.exe
        00000048    0
        00000054    0
        00000058    0     wine_sechost_service
        0000005c    0
        00000060    0
        00000064    0
        000000c0    0
00000068 winedevice.exe
        0000006c    0
        00000074    0
        00000078    0     wine_sechost_service
        0000007c    0
        00000080    0
        00000088    0
        00000090    0
00000084 plugplay.exe
        0000008c    0
        000000a0    0
        000000a4    0     wine_sechost_service
        000000a8    0     wine_rpcrt4_server
00000094 explorer.exe
        00000098    0
        000000c4    0
        000000c8    0     wine_rpcrt4_server
000000ac svchost.exe
        000000b0    0
        000000b8    0
        000000bc    0     wine_sechost_service
000000d0 rpcss.exe
        000000d4    0
        000000e0    0
        000000e4    0     wine_sechost_service
        000000e8    0     wine_rpcrt4_server
        000000ec    0     wine_rpcrt4_server
        000000f0    0     wine_rpcrt4_io
000000f8 conhost.exe
        000000fc    0
00000100 (D) Z:\Volumes\landatm\ext0\imagery\workspace\hsinju\LAStools\bin\las2d
em.exe
        00000104    0 <==
        00000110    0
System information:
    Wine build: wine-8.0.1
    Platform: i386 (WOW64)
    Version: Windows 7
    Host system: Darwin
    Host version: 22.6.0

Except this laz file, all the other laz files run successfully. Please let me know if you see any issue with this laz. Thank you!

[Jochen Rapidlasso]

Hi Hsin-Ju Li,

lasinfo give a overview about the file, this should be first if any problem occur:

ver:            LAS 1.4 [pnt=6|len=30]
point count:    14.263.011
scale x y z:    0.01 0.01 0.01
offset x y z:   0 0 0
min x y z:      -2,205,025.00 1,564,475.00 325.69
max x y z:      -2,204,475.01 1,565,024.99 562.92
range x y z:    549.99 549.99 237.23

LAS/LAZ files have a 4 byte value range. Your numbers stretch this range very well, without using a offset in your data.

The solution for this is quite simple:

lasoptimize64 -i -2205000_1564500.laz -o tmp.laz

will reorganize your data and set a suitable offset.

ver:            LAS 1.4 [pnt=6|len=30]
point count:    14.263.011
scale x y z:    0.01 0.01 0.01
offset x y z:   -2,200,000 1,500,000 0
min x y z:      -2,205,025.00 1,564,475.00 325.69
max x y z:      -2,204,475.01 1,565,024.99 562.92
range x y z:    549.99 549.99 237.23

After this, las2dem will process the data fast and efficient.

More notes:

- avoid *wine* if a problem occur, this will reduce one step of complexity. We have all LAStools able to run on linux.

- prefer the 64 bit versions of the tool if you work with windows tools. So best use "las2dem64" instead of "las2dem".

Cheers,

Jochen @rapidlasso