Canopy Button Results

Part of the analysis of global DEMs using point clouds, lidar and Icesat-2

Database created from canopy button.

FIELD_NAME
LAT
LONG
Z_SRTM	Elevation from SRTM
Z_ASTER
Z_ALOS
SLP_SRTM	Slope from SRTM
SLP_ASTER
SLP_ALOS
PC_SRTM	Percentile in the point cloud for the SRTM elevation -10, below entire cloud 100 above entire cloud
PC_ASTER
PC_ALOS
FR_SRTM	Fraction of SRTM in the point cloud: (SRTMz - Cloud.MinZ) / (Cloud.MaxZ-Cloud.MinZ)
FR_ASTER
FR_ALOS
CLOUD_PTS	Points in the point could
CLOUD_MAX
CLOUD_MEAN
CLOUD_MED
CLOUD_MIN
CLOUD_HT	Cloud.MaxZ-Cloud.MinZ
CELL_DZ	Due the median slope in the 3 DEMs, what would be the cloud height over 30 m
REC_ID

Canopy button. Histogram of the percentile within the lidar height distribution for the DEM elevations for 3087 points in Shenandoah National Park. The points at 110 indicate the DEM elevation is above all points in the point cloud, and those at -10 indicate all points in the point cloud are below the DEM.

Right clicking on the graph has an option to get a legend, which you can paste into the graph.

Canopy button. Histogram of the fractional position within the lidar height distribution for the DEM elevations for 3087 points in Shenandoah National Park. The points above 1.0, and below 0.0, indicate the DEM elevation is not within the point cloud. Because the elevation distribution within the point cloud is not uniform, this historgram is different than the previous one.

Using DB created by Canopy Button

From the DB created by the canopy button; no other data required.

Pick Location in one of two ways

Double clicking on a record in data base (can be challenging to get the one you want
ID button on map toolbar or database window, double clicking on the map, and then clicking the options button

From popup, pick "Point cloud and global DEMs"

Pick Lat profile, long profile, or Both profiles

Pick the tolerance in arc seconds. You want to get enough points, without have side slope distorting results

Lower left corner shows the parallel or meridian along which the profile runs

Right clicking on the graph has an option to get a legend, which you can paste into the graph.

Icesat-2 has challenges because the orbital tracks do not line up with the parallels and meridians, and you will see the gaps. The filter option below might be better.

The profiles for lidar are continuous.

Add beam and track to the database

Creates grids from the point cloud for the Point ID and User Data fields
Add the values from those grids into the DB

Filter the DB for the track and beam desired

From the Stats menu, Point clouds to analyze global DEMs,

Lat profile current filter
Long profile current filter

Last revised 1/26/2020