QGIS 4 Arch - LiDAR to DEM with LASTools 

And thank you for watching! Please, keep in mind some of my other videos explore alternative ways, I'm particularly found of cutting LASTools out of the equation and doing everything in CloudCompare. Of course, that's personal preference! :)

Great! Glad it is helpful. Also, check out my videos about processing LiDAR with CloudCompare alone. An alternative workflow that produces good results, and a totally open source solution as well!

Hey, that's great! Glad the video helped out! :)

Thanks for watching! Glad it was helpful. :)

You're welcome, glad to hear it!

That is often a problem with GIS, even worse, some paths in ArcInfo cannot use either a dash or underscore, can’t remember which - it’s not consistent though. Best to avoid all those.

Thanks!

You're welcome! Glad it was useful. :)

Thanks!

Thanks!

Thanks!

You're welcome!

Sir Hope We will Getting this Types of Tutorial more...by Your Quick Easily process... Thanks sir

hey I figured out that 3Ddem actually works fine. I just needed to extract the CRS information and apply it to the DEM layer that I generated in 3DEM, and all is well, FYSA it saves like a ton of steps to just use 3DEM and convert each LAS over to DEM, then merge. 3DEM doesn't use laz's tho. have to d/l LAS.

@@epicureanstoic5723 Apologies for not getting back sooner, but glad it worked out! :)

In my experiments it seems that good LiDAR (lots of successfully classified points, etc.) doesn't introduce much error because no additional spacing is introduced between the points across different files. This is only a problem with LiDAR of lower quality (poor classification, etc.). Of course, then error is introduced across the data, especially when points are poorly classified. I've had good experience re-classifying ground points using MCC-LIDAR (sourceforge.net/projects/mcclidar/). I am planning a video on that as well. Hope that helps!

@@ArchaeoSquatch Thank you for your feedback. I guess the way to check for "artifacts" would be to plot conours and check if there are any "blips" along the edge of each joint. However as you indicate its likely to be negligible.

Thanks for watching and the comments! So, I don't think LiDAR will show geological features (bedrock crevices, etc.). Basically, all LiDAR will record is the surface, and nothing below the surface, unless it impacts the surface landscape. So, a crevice will show up if it continues to the surface. Otherwise, you might try looking into infrared satellite imagery, which can often record subsurface features. Unfortunately, that's outside my area of expertise, but I suspect it would be a specific band combination like those discussed in this article about detecting subsurface lakes in Greenland (www.frontiersin.org/articles/10.3389/feart.2017.00058/full). I do have a video tutorial on using Sentinel imagery (as well as Landsat), which might help get you started? That link is ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-A99pMv4CFWg.html Apologies if I don't understand the question! :) To answer you other question, LiDAR is a 3D cloud of points, typically classified into different categories (ground, vegetation, buildings, water, etc.). A digital elevation model (DEM) is a raster dataset, basically a 2D image showing a subset of the LiDAR point cloud. As such, a DEM only shows the ground surface, by estimating the elevation of missing areas (ares without points) and removing all non-ground points from the classification process. Hope that helps!

@@ArchaeoSquatch You have answered my question quite well. Yes, the crevices I am looking for would be on the surface. Just buried under a lot of overburden. As stated, I have been trying to figure this out for almost two years in search of a trench I know exists. A trench that is going to hold the gold I am always on the hunt for! Thank you for the additional info as well. I will surly look into it. I truly enjoyed your video because you left no rock un-turned as to how it works. Well done! Most don't go into such detail.

Oh wow, that's a tricky one. I don't know of any sources, and usually can't even find it for my projects in the Caribbean either. Depending on what you're looking to do, perhaps the SRTM data will be sufficient? Here's a short video on using it - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-hneyz1yriKY.html

@@ArchaeoSquatch thank you for you quick response.

Honestly, I'd recommend using CloudCompare, here's my video on creating DEM and DSM from lidar - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eWo-CuTzlyw.html

Thanks! I'm not sure what's happening with that, might be an issue with the setting. You might also try to use my other workflow for LiDAR data, here's a link to the tutorial: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eWo-CuTzlyw.html&si=EnSIkaIECMiOmarE

I've not purchased a license myself, but you can find information about that here - rapidlasso.com/pricing/

I don't use Macs, but many of my students do. My understanding is that LASTools will not run on a Mac unless you use Wine or some other method for running Windows programs. UBC Geospatial Resources has a page describing the process, but it is 3 years old now - gis.ubc.ca/tutorial/installing-lastools-for-lidar-data-in-qgis-for-mac/. I created this video when I was still using LASTools, but in the past year I have fully transitioned to CloudCompare for all my point cloud processing needs, including working with LiDAR. I created a video that only uses CloudCompare and QGIS - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eWo-CuTzlyw.html. Hope that helps and thanks for watching!

@@ArchaeoSquatch Thank you so much for your advice. I am running into a world of problems trying to get Cloudcompare to work on either a PC or Windows program. It seems Windows 10 didn't have the MSVCR120 file in their systems folder. Downloading it and installing didn't help. With a Mac there was an issue reading the data type as well, some online threads pointed to the laz/las format the USGS or NOAA puts out as 1.3 which people were saying cloud compare couldn't handle and it somehow needed to be downgraded to 1.2 - I am not sure how to proceed. Your videos are super helpful, I just can't get much of the programs to work. The only workaround for now is through ESRI but I am looking for an open source option, and one that works very much like cloud compare. Thank you again for your response. On a side note, what PC operating system are you running? I am wondering if some of this is an OS issue?

This is likely because you've placed the LASTools folder/files in a different location than discussed in the video (see Installing LASTools section). This is a common mistake, I recommend saving this folder to you C: drive, that will fix the problem. Alternatively, follow the instructions in the video to point the LASTools within QGIS to the location on your computer where you saved the folder.

I'm not familiar with Mac computers, but using a Windows machine you can save the downloaded LAZ/LAS files anywhere on your hard drive.

Thanks for the comment. Unfortunately, I do not have access to a Mac computer. I did find this from the University of British Columbia, it may help even though it is a couple of years old - gis.ubc.ca/tutorial/installing-lastools-for-lidar-data-in-qgis-for-mac/.

@@ArchaeoSquatch Thanks for quick reply.

Yeah, been a while, will eventually remake these. When I do, I'll drop the LASTools video and either focus on QGIS's LiDAR tools, or the combo of CloudCompare and QGIS. Fortunately, I do have a video on using CloudCompare and QGIS! You can find it here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eWo-CuTzlyw.htmlsi=AJQEKABA3WQhn9F8

Absolutely! Use CloudCompare! :) I have a tutorial for that - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eWo-CuTzlyw.html

Without more details this could be hard to troubleshoot. You might want to uninstall and reinstall any plugins you are using. Also, starting with a clean profile often fixes this issue (according to some online forums). To fix this, click the Settings drop-down menu and highlight User Profiles. Then click New Profile and name it whatever you want. You may have to re-start QGIS. But, this often fixes issues like this for me.

A couple of things could explain this. This could be that LASTools is not installed correctly, which is covered in the video (make sure it is in the correct location and that settings is set to that). Sometimes, I think having the .laz/.las file in a path with spaces (e.g., C:/Users/Name/All LiDAR/) can cause an error. Honestly, I now recommend folks use CloudCompare. I have a very nice video about that workflow here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eWo-CuTzlyw.html

Thanks for the comment. I'm not sure what will happen with LASTools now that the developer has passed away. You can still download them from here: rapidlasso.com/lastools/download/ (I've updated the video's description as well). In all honesty, I prefer a non-LASTools workflow now, which you can learn about in my other video here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eWo-CuTzlyw.html. Hope that helps!

@@ArchaeoSquatch thanks for the reply! I got it.

Its probably not required since you've already removed the other points, but class 2 points are those classified as ground points. I do it as an added security step to make sure only ground points are used. :)

Hmm, not sure what that means exactly. Perhaps try processing the LiDAR with CloudCompare using my other video - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eWo-CuTzlyw.html

@@ArchaeoSquatch The issue ended up being a plugin maneuver. Once I got that sorted out, I was able to follow along, except now my processed DEM came out flat. 0 to 0 elevation, so now I just have a large grey brick. Maybe something missed or unchecked?

BTW, this is lidar data directly from USGS TNM, so I would think (hope!) that the data is good.

@@ArchaeoSquatch Running lasinfo again, I'm seeing what appears to be the issue: number of points by return: 0 0 0 0 0. Could this be the issue? There are 1.2mil points on first return though, but there are 3 warnings: WARNING: for return1 real number of points by return is 1204031 but header entry was not set. Any and all help much appreciated. Cheers!