Point Cloud Options
Points clouds are a category of GIS data.
This forms allow manipulation of the LAS point cloud.
||Tabs provided detailed option selection:
- File list
Create grids Create a new
grid that matches the DEM covering the map.
||Main controls on the bottom of the form, always visible:
Thinning for OpenGL, and slices
KML vertical offset, to put the points above the landscape.
||Files list tab. List of files to be used.
- LIB Add all indexed files from Map library
included on this map. Auto load from the
Map library set on the Indexes
tab of the options form,
automatically adds files when the form opens.
- Metadata: Display Metadata for the files. If there are a
lot of files, you probably only want to look at a few.
- Outline tiles on the current map
- Zoom: restrict map to just area covered
by the point cloud.
- On Map: do not open tiles that are not on the
map. If you zoom out, they will not automatically appear.
- Label: Label the tiles. You might
have to adjust the map colors to see them.
- Add #1, #2, #3, #4 Pick individual files/directories to included. You can
open multiple point clouds, and turn them on and off rapidly.
||Tools tab: Many of these options require that the base
map in use have a DEM associated with it, which will determine the size
of the grid created.
- Extract map LAS, Extract masked, Extract valid
- Extract points on the current map, which might be
in multiple files, into a single
LAS file or
3D shapefile. Pick
a small map area for this option.
- For mask option,
the current map must have a mask in red,
and only points that project to a red
pixel on the map will be extracted.
- For extract valid grid, only points
that map to valid values in the DEM
associated with the map will be
- Extract GeoJSON: for current map area, create
- Points above DEM, Points below DEM: puts the points above or
below the DEM on the map into the memo box on the right of the form.
This uses the Zcrit defined below.
Zcrit: buffer added to DTM before deciding if point is not on the
- Interpolate: get elevation with a bilinear interpolation.
- Floor/ceiling: get elevation from highest or lowest, as
appropriate, of the 4 grid nodes surrounding the point cloud
location. This can be better in regions of steep slope in the
- Histograms/Counts: histograms for elevation and
intensity, and a count of the returns in each category,
and by return number.
- Zero classification: merge all LAS
files in the current files listing into a single file,
with the classifications all reset to zero.
- Split by class: create new files by classification
(vegetation, buildings, ground, non_ground,
unclassified, and other)
- Recenter files: recenter all coordinates so that
multiple files share the same values. This is
designed for use with Cloud
Compare, and not at this time to create usable LAS
files for further analysis.
- Subset/tile: recursively quarter files until all
file sizes are under a specified value;
- Zero fields : set the following fields to zero:
Intensity, ReturnFlags, ScanAngle, UserData,
Compare two point clouds
Other Point Cloud Viewers and Lidar
Lidar Point Cloud Data Sources
File prep and work flow to create grids
Problems with point clouds
Last revision 1/7/2018