New answers tagged point-cloud
You could try and pull up a land use land cover database of your area where that code 0 is located in. It should be the similar one like this http://landcover.usgs.gov/landcoverdata.php but see if you have one the most recent current land use land cover of your area.
Further to Jeffrey Evans' answer, you could use PDAL to classify the ground points. It's a little harder to get started (on Windows, anyway) but it's free and makes high-volume batch-processing a cinch.
If the class codes field is not populated there is no way to obtain them. During pre-processing the vendor did not classify the points so, you are functionally dealing with a raw point cloud. Unfortunately, this means that you need to start researching methods for classifying the point cloud yourself. Since you did not provide any context I cannot aim you ...
There are plenty of ways to create a DTM/DSM in both programs. All tools are good, but can be tweaked to give you results based on your precise needs - of which you haven't included any - in your question. Take a look at these tools, all of which were also discussed on gis.stackexchange, to find the one to best fit your needs ArcGIS - Topo to Raster QGIS ...
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