Example 1: Static Datum

EXAMPLE 1: Static Horizontal Datum with Orthometric Vertical Datum using RTX Refined Reference Station Coordinates (@ L1 Phase Center)

• Data Collected : 06/18/21

• Desired output for LAS/LAZ: NAD 83 (2011) 2010.000 UTM 14 North Meters, NAVD88 - Geoid18

Horizontal Datum: NAD 83 (2011) 2010.000 UTM 14 North Meters

• NAD 83 is the North American Datum of 1983 and is fixed and stable relative to the North American tectonic plate.

• NAD 83 = Datum

• (2011) = Realization

• 2010.000 = Epoch

• UTM 14 North = Map Projection

• Meters = Units

Vertical Datum: North American Vertical Datum of 1988 (NAVD88) – Geoid18

• Note: Orthometric vertical datum’s require user to select a geoid model.

• For the United States, the GEOIDxx geoid models as been developed based on observations by NOAA’s National Geodetic Survey (NGS).

• These geoid models (e.g., GEOID 99, GEOID 03, GEOID12, etc.) provide the geoid undulation parameter (geoid height), so that the ellipsoid height from the NAD 83 three dimensional datum can be directly converted to the NAVD 88 orthometric height.

Navlab and LiDARMill Workflow

Project CRS Georeferencing

During project creation, select "NAD83 (2011)" as the project datum and select "Metre" for the project units.

Project Datum and Units

Next, select the Horizontal coordinate system "NAD83(2011)/UTM zone 14N" (Datum and Map Projection) and NAVD88 (orthometric vertical datum) as the vertical coordinate system + GEOID18 (Geoid model)

Horizontal and Vertical CRS + Geoid model

GCP Georeferencing

The project CRS should match the GCP CRS. You can verify the GCP CRS by clicking on the "GCP" tab within LiDARMill, and then clicking the button to the right of the GCP artifact, then click "Edit artifact"

Verify GCP CRS (Optional)

GCPs CRS should match project CRS

Reference Station Georeferencing

In step two of a Navlab Pipeline, select the NAD83(2011) refined trajectory. Navlab will automatically specify the epoch as 2010.000

Refined Reference Station Position datum

Output Trajectory Georeferencing

In step three of a Navlab Pipeline, select the output datum as NAD83(2011)

Select trajectory output datum

Export Pointcloud Georeferencing

LiDARMill may prompt the user to select the output coordinate system within the Spatial Fuser Pipeline. If it does not prompt the user, the Project CRS will be used.

Set Output CRS

Inertial Explorer and SpatialExplorer Workflow

Project CRS Georeferencing

Open the Project PLP in SpatialExplorer, and click on the datum at the upper right to configure the datum as NAD83(2011) and manually input the epoch as "2010.000".

Set Project Datum and Epoch

Verify the Datum and Epoch is set correctly

GCP Georeferencing

When importing GCPs into Spatial Explorer, Select the Horizontal CRS as "NAD83(2011) / UTM zone 14N" with units set to "metre" and select the Vertical CRS as "NAVD88 height" with units set to "metre".

Also select the desired Geoid18 geoid model.

GCP CRS input

Verify GCP CRS

Reference Station Georeferencing

During trajectory processing in Inertial explorer, configure the reference station datum as "NAD83(2011)" and the epoch as "2010.000".

Input RTX Refined Reference Station Position in NAD83(2011) datum and input Epoch 2010.000

Output Trajectory Georeferencing

In Inertial Explorer, select the datum "NAD83 (2011)" during the GNSS trajectory processing step

GNSS Trajectory Datum

In Inertial Explorer, select the datum "NAD83 (2011)" during the tightly coupled trajectory processing step

Tightly Coupled Trajectory Datum

Load Post Processed Trajectory into SpatialExplorer

When importing a post processed trajectory into SpatialExplorer, input the trajectory epoch as "2010.000"

Trajectory Epoch

Export Pointcloud Georeferencing

When exporting the final pointcloud, select the Horizontal CRS as "NAD83(2011) / UTM zone 14N" with units set to "metre" and select the Vertical CRS as "NAVD88 height" with units set to "metre". Also select the desired Geoid18 geoid model.

Exported LAS/LAZ CRS

Verify Output Coordinate System Before Exporting Pointcloud