NCSU GIS/MEA582:
Geospatial Modeling and Analysis

Geomorphometry I: Terrain Modeling

Resources: ESRI Academy

Launch ArcGIS Pro and login with ArcGIS Online credentials if required. Select New> Map> Create New Project. Create a new project in your preferred workspace, in the instructions below we are using the default C:\Users\myname\Documents\ArcGIS\Projects\ folder.

Use your judgement to decide which maps to include in your report.

Download the Raleigh 2013 lidar data as LAS file LAS tile 0793_016 in NC State Plane Meters and the orthophoto to the project. Unzip the file containing orthophoto.

Bring lidar data into ArcGIS

Analyze multiple return lidar data

Create a LAS dataset from .las point cloud

In the Geoprocessing pane, search for and select the 'Create LAS Dataset' tool
Set 'Input Files' to 'tile_0793_016_spm.las'
Set 'Output LAS Dataset' to 'lidar_all'
Be sure'Coordinate System' is set to 'NAD_1983_HARN_StatePlane_North_Carolina_FIPS_3200' (you can type 3358 in search window)
Check 'Compute Statistics'
Click 'Run'

View LAS dataset properties and filter points

In the Catalog pane, Right click on the LAS dataset and select 'Properties...'
Select the 'LAS Files' tab and take note of average point spacing (will use in later step).
Select the 'Statistics' tab to view point statistics by returns and classes.
Click 'Ok'

Right click on the LAS dataset in the Contents pane and click 'Properties...'
Select 'LAS Filter' tab.
Try applying several filter settings using classes and returns and view the results.
Check box next to '2 Ground' under 'Classification Codes'

With the LAS dataset filtered for ground points only, now we can analyze the point density of ground points and create a DEM with binning.

Compute a raster map representing number of points per cell (at two different resolutions)

In the Geoprocessing pane, search for and select the 'LAS Point Statistics as Raster' tool
Set 'Input LAS' to 'lidar_all'
Set 'Output Raster' to 'ground_count2m'
Set 'Method' to 'POINT_COUNT'
Set 'Sampling Type' to 'CELLSIZE'
Set 'Sampling Value' to '2'                            
Click 'RUN'
Right click on resulting raster in Contents and select 'Symbology'
Change color scheme to something appropriate.
On the 'Mask' tab, Set 'NoData' to red to highlight any areas with zero points.

Calculate point density at 6m resolution: (remember the tip with the geoprocessing history)

In the Geoprocessing pane, search for and select the 'LAS Point Statistics as Raster' tool
Set 'Input LAS' to 'lidar_all'
Set 'Output Raster' to 'ground_count6m'
Set 'Method' to 'POINT_COUNT'
Set 'Sampling Type' to 'CELLSIZE'
Set 'Sampling Value' to '6'                            
Click 'Run'
Right click on resulting raster in Contents and select 'Symbology'
Change color scheme to something appropriate.
On the 'Mask' tab, Set 'NoData' to red to highlight any areas with zero points.

Compute a raster map representing range of elevation values per cell at 6m resolution

In the Geoprocessing pane, search for and select the 'LAS Point Statistics as Raster' tool
Set 'Input LAS' to 'lidar_all'
Set 'Output Raster' to 'ground_range6m'
Set 'Method' to 'Range of Elevation Values'
Set 'Sampling Type' to 'CELLSIZE'
Set 'Sampling Value' to '6'                            
Click 'Run'

Use binning to compute a raster map representing average elevation per cell for ground points

Ensure that the LAS dataset is still filtered to include only class 2 (ground) points.
In the Geoprocessing pane, search for and select the 'LAS Dataset to Raster' tool
Set 'Input LAS Dataset' to 'lidar_all'
Set 'Output Raster' to 'ground_mean6m'
Set 'Value field' to 'ELEVATION'
Set 'Interpolation Type' to 'Binning'
Set 'Cell Assignment Type' to 'Average'
Set 'Void Fill Method' to 'LINEAR'
Set 'Sampling Type' to 'CELLSIZE'
Set 'Sampling Value' to '6'   
Set 'Z factor' to '1'                         
Click 'Run'

Use multipoint file to interpolate DSM from multiple return lidar data

Add some background data to give context:

On the Map tab, in the Layer group, click 'Add Data'
Browse to C:\Users\myname\Documents\ArcGIS\582data\ncshape.gdb
select  streets_wake
Select lakes
Select streams

Display orthophoto:

On the Map tab, in the Layer group, click 'Add Data'
Browse to C:\Users\myname\Documents\ArcGIS\582data
select ortho_0793_016_ncspm.tif

Create Multipoint files from .las point cloud and interpolate DSM

In the Geoprocessing pane, search for and select the 'LAS to Multipoint' tool
Set 'Input' to 'tile_0793_016_spm.las'
Set 'Output ' to 'lidar_first'
Set 'Average Point Spacing' to value listed in Files tab of LAS dataset properties, noted earlier.
Leave the 'Class Codes' empty
For 'Return Value', uncheck 'ALL_RETURNS' and check '1'
Set 'Coordinate System' to 'NAD_1983_StatePlane_North_Carolina_FIPS_3200' (you can type 3358 in the search window)
Click 'Run'

Interpolate DSM:

In the Geoprocessing pane, search for and select the 'Radial Basis Functions' tool
Set 'Input features' to 'lidar_first'
Set 'Z field' to 'Shape.Z'
Set 'Output raster' to 'lidar_spline'
Set 'Radial basis function' to 'Spline with Tension'
Click 'Run'

Find out what areas have multiple returns:

In the Geoprocessing pane, search for and select the 'LAS to Multipoint' tool
Set 'Input' to 'tile_0793_016_spm.las'
Set 'Output ' to 'lidar_multi'
Fill the rest as before but in 'Return values', uncheck 'All_RETURNS' and check values greater than 1. (2-8)

Optional - display the multiple return data as points in a Scene

FYI: Handling LAS data in ArcGIS

1. LAS Dataset or LAS file

2. Mosaic dataset

3. POint cloud scene layer