You can run this with Smart Oblique, nadir with altitude optimization (1 flight line of oblique from outside to center) or even with double grid oblique.
If you run double grid oblique you do not need the overlap listed since oblique images contain so much more of the scene in each image. I run double grid oblique 30 degrees with good results with 70/70 overlap. This will help if you need a 3D model and will now have less images to process.
GCP's will help to tighten up your data, so this is a good idea. Make sure they are not too close to the edges.
I would add more check points. I would do a minimum of 5 and possibly 10. Include check points at high and low areas and like your GCPs spread them out evenly.
I use 2ft x 2ft control points and have zero issue seeing and marking them. On projects demanding proven accuracy I do not use items in the area, only dedicated control point targets to ensure accurate marking.
Check points are how you prove your absolute accuracy, so do not have too few of them.
The water will most likely reconstruct poorly and you will most likely have to clean those points up manually in the dense cloud.
Do NOT use an ND filter. I have actually had very good sharp, focussed images with the current Matrice 4 E mapping settings.
Best results will come on a cloudy day with no shadows, but you would still want to map midday. The clouds will diffuse the lighting and remove shadows. I use Aperture Priority 4. The camera then adjusts the ISO and Shutter Speed. You'll notice that when the mission starts the drone will fly to the start point, position the camera angle autofocus once and then lock in that focus for the rest of the mission.
How much RAM does your computer have? This is where if you do not have enough your processing will fail or run forever.
I would also take a look at this article. It helps cleaning up the initial sparse cloud.
pubs.usgs.gov
Make sure you know what coordinate system datums:
I have good results in collecting control points in the same geographic system that the drone receives corrections in using ellipsoid elevations, and then allow Agisoft to apply the geoid undulation.
If you need a DTM, Agisoft does an okay job classifying points in my experience. Cloud Compare can do a better job if you know how to use it properly.
If you create contours though, I would not use Agisoft. I would thin out the dense cloud or even better make a grid of points with a point per 5 meters and then create contours from this. Contours look terrible from ultra dense point clouds with noisy ground.
Good luck on this project!
If you run double grid oblique you do not need the overlap listed since oblique images contain so much more of the scene in each image. I run double grid oblique 30 degrees with good results with 70/70 overlap. This will help if you need a 3D model and will now have less images to process.
GCP's will help to tighten up your data, so this is a good idea. Make sure they are not too close to the edges.
I would add more check points. I would do a minimum of 5 and possibly 10. Include check points at high and low areas and like your GCPs spread them out evenly.
I use 2ft x 2ft control points and have zero issue seeing and marking them. On projects demanding proven accuracy I do not use items in the area, only dedicated control point targets to ensure accurate marking.
Check points are how you prove your absolute accuracy, so do not have too few of them.
The water will most likely reconstruct poorly and you will most likely have to clean those points up manually in the dense cloud.
Do NOT use an ND filter. I have actually had very good sharp, focussed images with the current Matrice 4 E mapping settings.
Best results will come on a cloudy day with no shadows, but you would still want to map midday. The clouds will diffuse the lighting and remove shadows. I use Aperture Priority 4. The camera then adjusts the ISO and Shutter Speed. You'll notice that when the mission starts the drone will fly to the start point, position the camera angle autofocus once and then lock in that focus for the rest of the mission.
How much RAM does your computer have? This is where if you do not have enough your processing will fail or run forever.
I would also take a look at this article. It helps cleaning up the initial sparse cloud.
USGS Publications Warehouse
Structure from motion (SFM) has become an integral technique in coastal change assessment; the U.S. Geological Survey (USGS) used Agisoft Metashape Professional Edition photogrammetry software to develop a workflow that processes coastline aerial imagery collected in response to storms since...
pubs.usgs.gov
Make sure you know what coordinate system datums:
- Your drone collects images in
- Your GNSS Rover Collects in
- Your RTK Base Sends in
- Your client wants
I have good results in collecting control points in the same geographic system that the drone receives corrections in using ellipsoid elevations, and then allow Agisoft to apply the geoid undulation.
If you need a DTM, Agisoft does an okay job classifying points in my experience. Cloud Compare can do a better job if you know how to use it properly.
If you create contours though, I would not use Agisoft. I would thin out the dense cloud or even better make a grid of points with a point per 5 meters and then create contours from this. Contours look terrible from ultra dense point clouds with noisy ground.
Good luck on this project!
Thank you so much for taking the time to share your workflow - much appreciated!You can run this with Smart Oblique, nadir with altitude optimization (1 flight line of oblique from outside to center) or even with double grid oblique.
If you run double grid oblique you do not need the overlap listed since oblique images contain so much more of the scene in each image. I run double grid oblique 30 degrees with good results with 70/70 overlap. This will help if you need a 3D model and will now have less images to process.
GCP's will help to tighten up your data, so this is a good idea. Make sure they are not too close to the edges.
I would add more check points. I would do a minimum of 5 and possibly 10. Include check points at high and low areas and like your GCPs spread them out evenly.
I use 2ft x 2ft control points and have zero issue seeing and marking them. On projects demanding proven accuracy I do not use items in the area, only dedicated control point targets to ensure accurate marking.
Check points are how you prove your absolute accuracy, so do not have too few of them.
The water will most likely reconstruct poorly and you will most likely have to clean those points up manually in the dense cloud.
Do NOT use an ND filter. I have actually had very good sharp, focussed images with the current Matrice 4 E mapping settings.
Best results will come on a cloudy day with no shadows, but you would still want to map midday. The clouds will diffuse the lighting and remove shadows. I use Aperture Priority 4. The camera then adjusts the ISO and Shutter Speed. You'll notice that when the mission starts the drone will fly to the start point, position the camera angle autofocus once and then lock in that focus for the rest of the mission.
How much RAM does your computer have? This is where if you do not have enough your processing will fail or run forever.
I would also take a look at this article. It helps cleaning up the initial sparse cloud.
USGS Publications Warehouse
Structure from motion (SFM) has become an integral technique in coastal change assessment; the U.S. Geological Survey (USGS) used Agisoft Metashape Professional Edition photogrammetry software to develop a workflow that processes coastline aerial imagery collected in response to storms since...
Make sure you know what coordinate system datums:
Agisoft is excellent in regards to flexibility with this. Make sure you have the correct geoid undulation tiff if you need orthometric elevations and it is defined correctly in Agisoft.
- Your drone collects images in
- Your GNSS Rover Collects in
- Your RTK Base Sends in
- Your client wants
I have good results in collecting control points in the same geographic system that the drone receives corrections in using ellipsoid elevations, and then allow Agisoft to apply the geoid undulation.
If you need a DTM, Agisoft does an okay job classifying points in my experience. Cloud Compare can do a better job if you know how to use it properly.
If you create contours though, I would not use Agisoft. I would thin out the dense cloud or even better make a grid of points with a point per 5 meters and then create contours from this. Contours look terrible from ultra dense point clouds with noisy ground.
Good luck on this project!
In the end, we did evaluate both Smart Oblique and double grid oblique strategies prior to the mission. For this site, we opted for a balanced nadir + oblique approach primarily because shoreline geometry and vertical consistency around the water body are important for the intended construction planning use. The overlap strategy was adjusted accordingly to maintain strong tie point distribution while keeping total image count manageable.
On control: agreed completely regarding checkpoints. We placed distributed GCPs and additional checkpoints across elevation extremes and ensured none were positioned too close to boundaries. All were dedicated targets
Water reconstruction behaved as expected, some manual dense cloud cleanup was necessary in those areas. The vegetation belt around the shoreline required conservative ground classification as well.
Lighting conditions were favorable (diffused, near-midday), so no ND filter used.
Coordinate systems and vertical handling were predefined before acquisition and adjusted for our country's system.
Drone corrections/Rover
For the contours, I used a controlled thinning/grid strategy and it made much cleaner results for these types of deliverables.
Appreciate the confirmation on overlap efficiencies with double grid oblique, always good to compare methodologies with others running similar platforms.
Thanks again for contributing your perspective, it is really valuable!
Wish you a productive rest of the week.
