Re: [LAStools] Convert ASCII grid (ESRI) to LAS

[Nicolas Cadieux]

Unless I am wrong, the ESRI ASCII format is a raster format.  You could use gdal warp to do the job.  If the txt format is vector (xyz), then you could use Ogr2ogr also found in the gdal web site.  Then you could send is to a .las format using txt2las.

Nicolas Cadieux M.Sc.
Les Entreprises Archéotec inc. 
8548, rue Saint-Denis Montréal H2P 2H2
Téléphone: 514.381.5112  Fax: 514.381.4995

Le 2014-11-23 13:32, Jonas Lassen Jensen <lassen...@gmail.com> a écrit :

Hi Martin,

In our company we have urgent task that requires me to use the national free LIDAR dataset (Denmark) which is delivered in ASCII GRID format for ArcGIS. As the data is delivered in UTM I have to transform it into a danish national projection and convert the dataset to LAS-format. Will I be able to convert and transform the data to LAS-format with one of the LASTOOLS? I want to convert the dataset for me to be able to work with it in another software package. 

Thank you in advance.

Kind regards

Jonas Lassen Jensen

Tvilum Landinspektørfirma A/S

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[Martin Isenburg]

Hello,

if you have an ASCII GRID format for QGIS (the file format ending is *.asc) then you have a raster and not a point cloud. LiDAR is usually stored in *.las or *.laz files. Your raster is not raw LiDAR but a LiDAR-derived product that contains much less information than the original LiDAR point cloud. However, it may be sufficient or even more suitable for what you want to do.

All LAStools can directly read rasters from the ASC, the BIL, and FUSION's DTM format. Hence if your file end in *.asc, *.bil, or *.dtm then you can usually do:

lasview -i raster.asc

lasview -i raster.bil

lasview -i raster.dtm

with the ASC format (the *.asc file) being *by far* the slowest in terms of loading because ASCII formats are inherently poorly suited to store large data such as LiDAR or LiDAR-derived products. You could turn the ASC file to a LAS or LAZ file with

las2las -i raster.asc -o raster.laz

las2las -i raster.asc -o raster.las

If you use LAZ you should see amazing compression ... (-:

Martin @rapidlasso