Getting started with the Fusion program and LiDAR data

[James Parton]

Cool! Now I can get into this LiDAR stuff!

[edfrank]

Joe,

Yes it is accurate, but there are some caveats that require the results be ground-truthed.  There are limits to the resolution of the data, so there is some averaging and extrapolation at this level on both the ground surface and tree tops.  The LIDAR likely will not resolve the finest branches that make up the extreme top of the tree.  It is measuring the distance between the tree top and the ground directly below the top, which might not be the same as the base of the tree.  This is a particularly important variable on areas of steeply sloping ground.  It works best on areas that are generally flat.  But with all that being said, from what people have posted it appears to be a fantastic tool for scouting out an area looking for tall trees.  You would still need to visit the site and determine the species of the tall hits and confirm their heights.  For species that are not the tallest, the area still needs to be scouted and measurements made.  If all the tall trees on a site are sycamores, the site still should be visited to measure other species and to look at species diversity, girth etc.  So LIDAR a big thumbs up as a scouting tool, but sites still need to be visited, and if you are looking for old growth - the LIDAR tells you nothing about the age structure of a site.  It could be a site dominated by young tall trees, while an older forest on a less ideal site may still be relatively short.

Ed

[Matt Markworth]

Steve,

 Thanks so much for sharing your process on how to analyze the OGRIP files with Fusion. Your step-by-step explanation made it easy to jump in and get started.

 So far I've used it for scouting purposes, but now I want to find the individual trees that caused the tallest hits. Utilizing the view of the terrain has put me in the right area, but I want to use latitude/longitude to ensure that I'm not misreading the terrain and that I'm actually in the right spot.

 I haven't been able to figure out if Fusion can show the latitude/longitude of a specific point, but I've been able to find it using this method. If anyone knows how to pull latitude/longitude directly from Fusion, please let me know.

1) Use the LIDAR Data Viewer to pinpoint the tallest hit.

2) Select a very small area on the Fusion image that includes the tallest hit.

3) Right click on the Fusion image until the individual tree is visible.

4) Compare the Fusion image with maps.google.com and line up a couple landmarks, and match up the location of the tree. Use the “What’s Here” functionality on maps.google.com to find the latitude/longitude.
Or,
Compare the terrain on the LIDAR Data Viewer with the terrain on the USGS National Map Viewer. Place the cursor on the spot of where the tree would be on the USGS National Map Viewer and the cursor position will show the latitude/longitude.

5) For verification purposes, enter the latitude/longitude into the OGRIP site and make sure that the tree image matches the tree image that was on the Fusion image.

- Matt

[Steve Galehouse]

Matt-

I've also tried to get lat/long co-ords directly through Fusion, without success. There must be a way to do so, as the viewer screen has a button for GPS values. I end up doing something similar to what you do, but I've found Big Birdseye images to be more helpful than google.maps. The tall trees in my area are nearly always associated with topography that readily relates the screen image to the actual location.

Steve

[Matt Markworth]

Steve,

Sounds good, thanks again for the help and for the suggestion. For a site that I just checked, Google has leaves on and Bing has leaves off. The image from OGRIP has leaves off, which matches up nicely with Bing.

-Matt

[Jimmy McDonald]

Wow this could be amazing.  Thanks for the instructions.  I was able to get it to work.  How would I go about getting info for MN or other states?

[Jess Riddle]

Steve, Matt;

If your just interested in the highest points, there is a clunky way to get coordinates out of Fusion.  Try Tools->Terrain model->describe terrain model then select the canopy height model that you're interested in.  In the "Describe DTM" window that pops up, hit the "view elevation data" button.  A new window should open with a contour map of your canopy height model.  Increase the contour interval to slightly less than the tallest trees.  You should then see a nearly blank map with a few small rings that indicate where the highest canopy is.  Move your cursor over the tall tree area of interest, and the X and Y boxes will display the coordinates in the same units as the original LiDAR data.

Jess