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In this tutorial, I will show you how to convert DEM/DTM/DSM files to LAZ/LAS files. Because Chad's Tool is only support las/laz file format (classified cloud point Lidar file). But the lidar data not cover all the place, somewhere we only have DEM files. DEM file is not perfect, it only provide the ground elevation, no trees, buildings information, but have something is better than nothing. The DEM, DTM and DSM is very similar file format, we use same way to convert them to las/laz format. In this tutorial, I just show you how to convert dem to las/laz. LAZ file is zipped las file, so laz file is better than las.
Tools we need here are all totally free.
The first tool is QGIS, and you must install an plugin "Lastools", we will use this LasTools later.
The other freeware we need is SAGA
After you install those freeware and plugin, now we get started.
1. Drag and drop the DEM file into QGIS and open its properties, record the ESPG and Projections value, we will use this values later.
2. Convert Raster DEM to GRD format. I create a folder "D:\LIO". You can create any other folder name you like.
3. Now we open SAGA software. Open the upon output .grd file with SAGA, you can drag and drop the .grd file into SAGA.
4. Look for tool "Point Cloud from Grid Point" in SAGA, and convert it to point Clouds format.
Conversion interface:
5. Look for tool "Export Point Cloud to Text File" in SAGA, to export txt file. I export all the .txt file into "D:\LIO" folder, we will use this folder later. You can create any folder name you like.
Exporting interface 1:
Exporting interface 2:
6. Go back to QGIS software.
7. Look for the tool "txt2las" in "LasTools" plugin. Double click to run it.
8. Set all the values as below, the most important thing is to set all the point type to 2 (ground type), use "-set_classification 2". Otherwise Chad's tools won't recognize the point type, and report an "unclassified cloud point" error message. The EPSG and Projections value, we already got them instep 1, now input them. Output file size select LAZ. LAZ is a better file format than .LAS. Chad's tool can support laz files very well. You can run single file conversion, or you can also run batch conversion for multiple files in same folder. Please refer the following to screenshot, one for single file, one for multiple files.
Convert single file.
Convert multiple files.
9. Done. Congratulations. You learned all what I know.
Tools we need here are all totally free.
The first tool is QGIS, and you must install an plugin "Lastools", we will use this LasTools later.
The other freeware we need is SAGA
After you install those freeware and plugin, now we get started.
1. Drag and drop the DEM file into QGIS and open its properties, record the ESPG and Projections value, we will use this values later.
2. Convert Raster DEM to GRD format. I create a folder "D:\LIO". You can create any other folder name you like.
3. Now we open SAGA software. Open the upon output .grd file with SAGA, you can drag and drop the .grd file into SAGA.
4. Look for tool "Point Cloud from Grid Point" in SAGA, and convert it to point Clouds format.
Conversion interface:
5. Look for tool "Export Point Cloud to Text File" in SAGA, to export txt file. I export all the .txt file into "D:\LIO" folder, we will use this folder later. You can create any folder name you like.
Exporting interface 1:
Exporting interface 2:
6. Go back to QGIS software.
7. Look for the tool "txt2las" in "LasTools" plugin. Double click to run it.
8. Set all the values as below, the most important thing is to set all the point type to 2 (ground type), use "-set_classification 2". Otherwise Chad's tools won't recognize the point type, and report an "unclassified cloud point" error message. The EPSG and Projections value, we already got them instep 1, now input them. Output file size select LAZ. LAZ is a better file format than .LAS. Chad's tool can support laz files very well. You can run single file conversion, or you can also run batch conversion for multiple files in same folder. Please refer the following to screenshot, one for single file, one for multiple files.
Convert single file.
Convert multiple files.
9. Done. Congratulations. You learned all what I know.
. Looks like you are becoming the expert on conversion of these other formats into .las
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