topic Re: Help with Lidar in LIDAR Resources Questions

Help with Lidar

BenWilkerson — Tue, 12 May 2020 13:36:14 GMT

Hi All,

I downloaded Lidar data from NOAA and am looking to use it to assess possible trout spawning areas in the Lower Saluda River in South Carolina. The data I downloaded is in TIFF format. What are some possible workflows that I could execute to assess the data to find spawning habitat in the river? I know how to perform trained classification with imagery on ArcGIS but are there other tools out there to undertake this task? Any help would be greatly appreciated. Thanks!

Ben

#lidar solutions‌ #lidar and other point clouds‌

Re: Help with Lidar

DavidPike — Tue, 12 May 2020 15:12:12 GMT

I'm guessing you have some bathymetric LIDAR? What influences trout spawning areas? Or do you already know the areas and are trying to infer water depth to be causal?

Re: Help with Lidar

BenWilkerson — Tue, 12 May 2020 15:42:18 GMT

David,

The Lidar data I downloaded is in LAS point data. The metadata also states that a DEM, hydrographic breaklines and terrain, and intensity images per tile.

I know that trout spawn in shallow water on gravel beds. I was hoping to use the Lidar imagery to find those areas.

Re: Help with Lidar

DavidPike — Tue, 12 May 2020 17:04:20 GMT

I'm thinking a slope/roughness calculation might identify the gravel, and shallow areas could be identified through the difference of the point elevation to mean water level?

Re: Help with Lidar

SteveKopp — Tue, 12 May 2020 19:10:47 GMT

Yes with your understanding of ArcGIS image tools and supervised classification you could do this assuming: a) the lidar data has picked up some information that is indicative of spawning habitat b) you have known spawning areas to use for training.

Your ideas of using roughness seems good if you can derive that from the lidar. Unless the point spacing is very tight it will be hard to distinguish spawning gravel (1/4 inch to a couple inches depending on your fish size), from finer sediments and mud, but you might be able to use supplemental imagery to help with this.

For the depth, take a look at the Height Above Nearest Drainage workflow described in the reply to this question.

Here is a pretty relevant project - Modeling salmon spawning habitat from lidar PDF and other project info and downloads

And another somewhat related - Spawning lake trout in Yellowstone