GCP's to improve accuracy | Solutions Knowledge Hub

You can create more accurate point clouds using GCP in conjunction with PPK. Please prepare the drone image with GCPs and coordinate information of GCP.

Select "Use PPK and GCP" in step 4 (p.38) of "Generating Point Clouds".
Tap the "Import Flight Data" button and select the drone data to upload to the EdgeBox from the displayed dialog.
The imported data will be listed. You can also select and multiple imported data.
Check the flight data to generate point cloud from the imported data list and tap "PPK processing start" button.
A dialog showing the PPK Fix rate will appear, check the rate and press "Next"

A low PPK Fix rate may affect the accuracy of the resulting point cloud. At the point where the red × mark on the drone flight route has a worse acquisition of the drone location. Please confirm and fly again if necessary.

Check the flight data to generate point cloud from the imported data list and tap " Start PPK processing" button.

If you tap ''Conditions which was able to generate point cloud'' The number of photos loaded and the maximum number of photos processed at each density can be checked.

Unnecessary object removal:

When you toggle ON, it removes unnecessary objects, such as buildings and vehicles, that are not needed for soil volume calculations.

Additionally, you have the option to "Select Category" to keep other categories such as "Short Grass and Road Surfaces."

Short grasses" can remove/retain all vegetation (distinguish short grasses from v4), and
"Road Surface" can remove/retain road surfaces, including concrete.

Point Cloud Density ：Adjusts the density of the point cloud as required.

16ppm is recommended for most surveys

3D accuracy check requires Ultra high density. There’s area size limitation with this setting.

level	density	Maximum processing area
level	density	Point cloud + ortho +Unnecessary object Removal point cloud	Point Cloud + Ortho	Point cloud+ Unnecessary object Removal point cloud	Point clouds only
Ultra-high density	280p/m2	5 ha	5 ha	10 ha	10 ha
High-density	100p/m2	15 ha	15 ha	30 ha	30 ha
Standard density	16p/m2	50 ha	50 ha	50 ha	50 ha

Ortho and DEM image generation:

Generate Orthophoto & DEM (Digital Elevation Models).

If you do not turn on ortho generation, you will not be able to output an image showing the verification point positions on the ortho, which is the 3D accuracy check report material.

Insert the USB memory with GCP coordinates file (.csv) in the USB slot of SMART CONSTRUCTION Edge. Please refer the file format.

Insert the USB memory into the USB slot (inside the waterproof lid) ④ of the EdgeBox

① Status LED

② SD card slot

③ Ether cable port

④ USB slot（USB3.0）

⑤ SIM card slot

⑥ Water-proof USB slot（USB2.0）: cannot use this slot for USB memory

Tap the "Import Point File" button and specify a CSV file from displayed dialog, which containing coordinates of GCP. You may select “Add Control Point” if you manually add a control point.

You can also manually input coordinates
Set the file format parameter according to the file and tap “OK”.
Tap edit button of each GCP to display a thumbnail of the image that may have the selected GCP in the image.
Tap the thumbnail of the image, align the center of the cross mark to the center of GCP in the image, and tap "OK"

Make sure to stay close the Edge to maintain good Wi-Fi connectivity while tagging GCP’s

You can zoom in and out by pinching in and out, move the displayed portion by swiping.

More than four images are required to align a GCP. The more you tag the better accuracy can be achieved

At least more than 1 GCP must be selected and aligned like this. If you proceed without selecting a GCP, point cloud is generated only with PPK.

When you finish matching the coordinates of the GCP (at least 4 of them) with the image center, tap the "Done" button.
Set the parameters of point cloud generation and tap the “Start” button.
The point cloud viewer screen shows up and the point cloud generation process starts. During this process, it is possible to switch to another window and perform the other work. You can check the generated point cloud by selecting it from the list on the project top screen.

To generate a Digital Elevation Model (DEM), both the Unwanted Object Analysis and Ortho Image Generation settings must be both ON.