[GRASS-user] Processing LiDAR data in GRASS GIS

[Adrian Kirilov]

     *Hello to all users of GRASS,*
*
*
*     I have LiDAR data in ASCII txt files with only X, Y and Z
coordinates, which I want to import and create DEM models from in GRASS.
I'm new to this kind of data processing.*
*     *
*     I'am using the following approach in a new MAPSET:*

     db.connect driver=sqlite
database=$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite.db
     v.in.ascii input=b29_3.txt output=b29_3 fs=space z=3
     g.region vect=b29_3 -p

*# I tried few times at this point to interpolate the points with IDW using
v.surf.idw. It stated that I have to show in which column of the attribute
table are Z values in order to execute the command.*
*   At this point I don't have an attribute table yet created for the
vector map b29_3...so I tried this one:*

     v.db.addtable map=b29_3 at testMapset11 columns=cat integer, x double
precision, y double precision, z double precision

 #* ...and after that:*

     v.to.db map=b29_3 option=coor columns=x, y, z
*
*
*# for to populate the database with and finally use v.surf.idw*

     *Is it my approach correct because it takes too much time (I mean few
hours for only one txt file with 3 500 000 points) and it's very slow...and
I'm really not sure how to proceed? And if no what is the correct one? *
*     *
*     I tried also to create an attribute table even with v.in.ascii when
still importing the data, but I don't have attributes and it doesn't create
tables only for X, Y and Z coordinates (I don't know why).*
*
*
*     Any help will be highly appreciated! Thank you!*
*
*
*
*
*     Greetings,*
*
*
*     Adrian Kirilov*
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