Tennessee LiDAR

[millermccoy]

Anyone know the procedure to get TN LiDAR contours into 2018 Civil 3D?

[Pointdump]

Hi Greg,
What's your data? What file format?
Dave

[Pointdump · Accepted solution]

Greg,
I was just looking at Tennessee's website. Boy oh boy, I see why you are asking.
"...data products in point cloud (.zlas), DEM (.img), Building Footprints (2D & 3D), and contours (.gdb)..."

For the ESRI proprietary format zLAS you'll need to use LASLiberate in LASTools to convert to LAS format. Then you can run it through ReCap.
For the ERDAS Imagine proprietary format IMG you'll need to use QGIS to convert to TIFF format.
For the ESRI format GDB you'll need to use QGIS or GDAL to convert to shapefile format.
Dave

[millermccoy]

thanks for your input.

I got it to work using the videos in this link...

https://www.tn.gov/finance/sts-gis/gis/gis-resources-news-events/gis-instructional-videos/using-tn-l...

[Pointdump]

Greg,
Good videos!
Dave

[Pointdump]

Greg,
I grabbed one of the Tennessee zLAS files to play with. I couldn't get LASLiberate in the LASTools to work. (I've used it before. They must have broken it.) ESRI has a standalone program called EzLAS to convert from their proprietary zLAS to LAS. It works very well and can be downloaded >>>Here<<<. Then you can drag that LiDAR data into ReCap and use Automatic Ground Classification to filter Ground(2) points. When you import the RCP file into Civil 3D you can further filter points by spacing to avoid the Kiss-Of-Death MMS file.
Dave

[TerryDotson]

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Then you can drag that LiDAR data into ReCap and use Automatic Ground Classification to filter Ground(2) points.

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I have to strongly disagree with the process of taking an already classified lidar file and running it through any software, especially one with less a year history on its classification process.  The original classification was likely the result of careful processing by individuals familiar with the area and using high resolution images as underlays.  As such they can *see* buildings and other structures as opposed to software working on a blind algorithm.

If a lidar file has no existing classification, then by all means see what the software can do.  Otherwise trust the knowledge and experience of the providing agency!!!  Just because s software package removes some extra points does not mean it's better.

[Pointdump]

Hi Terry,
ReCap can also just filter Ground(2) points without using the Automatic Ground Classification routine.
LasGround and CloudCompare also have the ability to further "refine" ground points. Even though the points have been classified, there is always noise and mis-classified points in with the Ground(2) points, so we'll just have to agree to disagree on that point.
The main point of my post was how to convert the proprietary zLAS file format to a more usuable LAS format.
Dave