[question] What is the simplest way to feed data to LAG?

[rulatir]

What is the simplest data format that LAG supports? By "simple" I mean something that can be programmatically generated in a few lines of code from data in an array, without dragging the entirety of liblas into the picture.

EDIT: due to a distro quirk, I cannot have lastools and LAG installed simultaneously. Therefore conversion tools offered by the lastools package are not available to me.

[ada-foss]

Csv 🙂

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On Thu, 16 Apr 2020, 23:31 rulatir, ***@***.***> wrote: What is the simplest data format that LAG supports? By "simple" I mean something that can be programmatically generated in a few lines of code from data in an array, without dragging the entirety of liblas into the picture. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#37>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAQGOVXUPLWVXW7FANOH5VLRM6BKRANCNFSM4MKH7SCQ> .

[rulatir]

There isn't one, unique CSV format. Headers? Mandatory columns? Just feeding x, y, z rows doesn't work: it processes the whole file, but draws no points.

[ada-foss]

It's been so long I can't remember. It might take a fixed format for the columns with which you can stuff dummy data or it might read the header to decide what is what. I'll check the source code for you tomorrow.

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On Thu, 16 Apr 2020, 23:34 rulatir, ***@***.***> wrote: There isn't one, unique CSV format. Headers? Mandatory columns? Just feeding x, y, z rows doesn't work: it processes the whole file, but draws no points. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#37 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAQGOVXCLVNNCJ6P4YDABYTRM6BY7ANCNFSM4MKH7SCQ> .

[ada-foss]

LAG depends on lastools for a generic LAS file reader class and that is what supports las, csv, and txt files. If you can't install the lastools library dependency then LAG would not even open, it would fail at the dynamic linking step as the program loads.

If you are getting as far as the "Open a file" dialogue you must have satisfied the lastools library requirement. Perhaps that is where your clash is even coming from. If your data is in las format already then just load that directly, trust me loading large datasets blown up into human readable form is an exercise in pain.

To load any txt or csv type data you must specify a "parse string" which is fed directly to the lastools library. I'm having a really hard time finding any documentation for how parse strings are constructed and the code where this is implemented is uhhhh.. special..

https://github.com/arsf/LAStools/blob/2e1f95b15cacae8d12f3bdaa6c455e22adcd3509/LASlib/src/lasreader_txt.cpp

But for simple point data I found this example in the lastools suite

txt2las -i %INPUT_FOLDER%\%INPUT_TRAJECTORY%.txt ^
        -parse txyz -skip 1 ^
        -odir %OUTPUT_FOLDER% -o %INPUT_TRAJECTORY%.laz

So if all you need is xyz data then I think you can encode your data in the form

50.0984 71.3217 15.15
50.0993 71.3272 15.01
50.0953 71.3293 14.62

and specify a parse string of "xyz"?

I'm not sure how it handles csv files because looking at the code it doesn't seem to have any special clauses for csv files like it does with las, txt and other formats. Perhaps I'm looking in the wrong place and LAG does some conversion of commas to spaces on the way through if you specify a csv file. But you will still need a parse string.

[rulatir]

Clarification: I am using lag-git from AUR, which depends on one of the two packagings of lastools - specifically the one named laslibs rather than lastools. The laslibs package contains the library only, not the binary utilities. There is a lastools-git package in AUR, but it conflicts with laslibs.