Messages

61

General / Re: My drone mapping project using GCPs from Pictometry and LiDAR

« on: April 17, 2022, 10:54:06 AM »

Since I first started looking into photogrammetry I've been wondering why ground control points are exclusively considered to be square targets that you put on the ground.

This is incorrect.  Ground targets are generally used because in many / most areas being developed, there is not established infrastructure in place that can be used reliably to establish centimeter level precision when developing a 3d model.  In cases like yours where there is plenty of substantial, identifiable objects that can be measured and assigned coordinates, they are fine and often preferable because they are permanent.

I learned a lot in the past few weeks, but I only have 6 days left on my trial, so in a week I'll have to switch to another program that I can afford. Unfortunately there is no product from Agisoft that lets someone like me do this kind of non-commercial mapping I hope they consider some kind of home use or hobby license. The standard license is fine for objects but without geographic capability it's not useful for documenting landscapes

This service was recently suggested by Agisoft where you can run projects and pay for only what you use.  Maybe it might be an option for you.

https://www.geocloud.work/

Is there a way to export the marker locations on the photos that other programs like Reality Capture can interpret?

Yes.  Similar to the importing of .csv coordinates, you can also export marker and/or camera positions.

I have yet to see discussion on any forum, Facebook group, or a tutorial about using ground control points that aren't GPSed checkerboard pads. Discussion of using manholes and things like that may exist somewhere but I haven't seen it!

The Geocloud thing may be an option, but just uploading photos would take days because this particular project is over 8GB of JPEGs. I'm guessing the costs would get pretty steep for by the hour work... I think I've spent 40 hours or more on this

I'm going to try importing a "bundler" file to Reality Capture. I installed it today and started working on a new project... I don't have high hopes. I can't get it to import my ground control points properly, the coordinates get totally changed. And the UI is atrocious

62

General / Re: My drone mapping project using GCPs from Pictometry and LiDAR

« on: April 16, 2022, 10:33:02 PM »

I want to keep working on this project, adding more photos and expanding the area to cover a lot of the coastline in Makena. But I have over 500 photos in the sunny weather project, most with GCP markers. Is there a way to export the marker locations on the photos that other programs like Reality Capture can interpret? I've spent hours placing them and I don't want to have to do it again. I only have 4 days left on the trial so I don't have much time to figure this out!

63

General / Which Optimize Camera Alignment Parameters should we use?

« on: April 16, 2022, 10:20:28 PM »

The manual says what the different checkboxes mean on the Optimize Camera Alignment dialogue, but doesn't explain when or why you would use each one. The last 3 are disabled by default, but I've seen user made tutorial videos where they check all but without an explanation. I usually check all except the Advanced boxes, when I optimize alignment after adjusting my GCP markers. Is this correct? Or should I be using the default settings? Does it depend on the type of camera?

64

General / Re: Adding markers from excel or csv

« on: April 16, 2022, 09:33:59 PM »

I found that page and couldn't find "import button the reference pane" because I was expecting something looking like an import button. I think they need usability streamlining

65

General / Re: Adding markers from excel or csv

« on: April 16, 2022, 11:01:04 AM »

Thank you, I don't think I'd ever have found that tiny button

66

General / Re: Adding markers from excel or csv

« on: April 16, 2022, 02:30:42 AM »

You also can import markers from a .csv file. it is very easy to do. I do it sometimes.

But how? I found that you can export a .shp and then you can display them on the ortho and select them. You can right click and choose "attach markers" which doesn't work. How do you get the program to read the points and the fields and use those to create markers?

67

General / Re: 16bit instead of 8bit source images- better mesh quality?

« on: April 15, 2022, 11:33:16 AM »

We're shooting on a Canon RP in a (small!) studio environment. I checked the spec and C3-Raw should deliver 14bit. I don't see the point of rendering tonemapped jpgs from that. The question remains: Rendering 16bit tiffs or exrs from that raw-footage. Does this help Metashape in aligning cameras, conserving more details in mesh?
Thank you, guys!

There would be a benefit for your textures because you can adjust color, exposure, bring up shadows, etc

68

General / My drone mapping project using GCPs from Pictometry and LiDAR

« on: April 15, 2022, 09:27:49 AM »

I've been doing GIS for about 15 years and majored in geography. Since I first started looking into photogrammetry I've been wondering why ground control points are exclusively considered to be square targets that you put on the ground. In GIS we usually georeference aerial photos, scanned maps, etc using existing imagery to find features on the ground.

Well over the past month have been using Agisoft Metashape Pro trial to learn drone photogrammetry. Previously I had only generated simple orthophotos using Maps Made Easy and Pix4D

I work at Maui County where we have access to high resolution orthophotos from Pictometry. In Hawai'i we also have a pretty extensive set of LiDAR data for coastal areas and with the full state coming later this year. Both are available to the public through ArcGIS Online which is good because I'm doing this as a personal project. Since I don't have access to a high precision PPK GPS receiver, or access to some of the places I wanted to map, I decided to try using the Pictometry and LidAR as a source for GCPs

The first landscape I've mapped is a heiau (Hawaiian shrine or temple) on a small knoll here on Maui. It's preserved but surrounded by development. The landscape that provides context for the heiau is almost completely altered and soon buildings will be blocking the viewsheds, and even oblique drone views, so I needed to collect photos ASAP. I went out around solar noon on a few weekends and manually collected raw photos with my Parrot Anafi drone. Some were in cloudy weather so I separated sunny/cloudy into separate projects. I applied Colorchecker profiles in Lightroom except for the set of JPEGs I got with Pix4D Capture (I don't recommend this program, it collected distortion corrected images and all with different white balance and exposures)


I found a set of features on the landscape that are visible on Pictometry and my drone photos, mostly electric company concrete pads and manholes. I found coordinates by placing features in ArcGIS Pro and calculating latitude/longitude in WGS84. I then grabbed elevations from the closest LiDAR points. Many of the LiDAR elevations aren't totally accurate because they were collected before construction of the infrastructure but I think they're close enough


I didn't use all of these GCPs, I tried to choose ones that were widely spaced from each other just like we do when georeferencing flat maps


For the sunny weather project I used 521 photos to generate the model, from many different elevations and angles, but only the low altitude (25m) for generating textures and orthomosaics


The orthophoto from Agisoft matches Pictometry almost exactly, which is what you'd expect. I can't say how accurate it is, but it would be the accuracy of the imagery plus whatever error is introduced in the georeferencing process. I believe the Pictometry rating is "below 1 meter" but it varies with location. More importantly, the orthophoto and 3D model match an existing reference set of imagery that is standard for government and related uses in Hawai'i, and future orthophotos will match the existing ones allowing direct comparison. Also, since Pictometry is already orthorectified, any error should just be simple shift, so future adjustment will be easy!


Another orthophoto from the cloudy weather project:

 
I think this is the power of a 3D model... Our brains can really understand a landscape if we can see a 3D model. A photo from a drone is a view from one vantage point and has perspective distortion. Viewing from the ground is even less helpful. I learned only from looking at my model that the lot is already built up much higher than the two knolls, so the mansions will tower above. I'm not sure this development would have been approved if the community could see and understand the landscape in three dimensions

 
I learned a lot in the past few weeks, but I only have 6 days left on my trial, so in a week I'll have to switch to another program that I can afford. Unfortunately there is no product from Agisoft that lets someone like me do this kind of non-commercial mapping I hope they consider some kind of home use or hobby license. The standard license is fine for objects but without geographic capability it's not useful for documenting landscapes

69

General / Re: Error message "Incompatible keypoints"

« on: April 14, 2022, 04:41:04 AM »

I did exactly what the manual says

1- I started with a project that already had a dense cloud made

2- Then loaded new photos taken on a different day

3- Added a few markers to new photos

4- Ran align with "reset alignment" unchecked

5- Got error message

Also tried without step 3 and same error

70

General / Re: 16bit instead of 8bit source images- better mesh quality?

« on: April 13, 2022, 11:08:08 PM »

I don't know the answer to this but I have learned to only use raw photos, because of the color correction and adjustment possible. I tried using JPEGs collected with my Parrot Anafi using Pix4D Capture and it turned out terrible because white balance and exposure were inconsistent, with no way to get all images looking the same.

With the raw files, I can use my Colorchecker Passport to get an accurate profile for the lighting conditions, and also apply the same white balance. With 2 different cameras I think it's even more important to capture raw so you can get colors to match as much as possible between cameras

71

Camera Calibration / Re: Placing markers increase cameras error after optimization

« on: April 13, 2022, 04:36:34 AM »

I'm new to photogrammetry and therefore not an expert, but I've been georeferencing flat images for over a decade in GIS. I'm pretty sure what you're seeing is that once you give the system accurate GCP coordinates, it now knows the errors in the GPS coordinates on the photos. If all it has is GPS data, it has no idea how accurate it is

72

General / Re: Error message "Incompatible keypoints"

« on: April 12, 2022, 09:29:38 PM »

Hello DayGeckoArt,

Thank you for sharing additional information related to the project. I would say that the problem could be related to the chunk merging operation - can you please confirm, if it has been performed for this project?

If chunk merging has been applied, please specify the processing parameters (of Align Photos stage) used for each chunk, and also specify, if Merge Tie Points option has been used for the chunk merging procedure.

No merging because I didn't append a new chunk, I only added the new photos direclty.

I have done an append and a merge chunk with another project and that worked fine

73

General / Re: Change path/replace photos

« on: April 12, 2022, 04:00:04 AM »

Hello DayGeckoArt,

Seems that you have a typo in the posted script - ch.cameras list element is not defined. Also I suggest to skip Animation track cameras to avoid unexpected issues:

Code: [Select]

ch = Metashape.app.document.chunk
for i in range (len(ch.cameras)):
    if ch.cameras[i].type != Metashape.Camera.Type.Regular:
        continue
    ch.cameras[i].photo.path = ch.cameras[i].photo.path.replace(".tif", ".jpg")

EDIT: Ooops what I pasted above isn't what ended up working. This is what I did that has worked in a couple projects:

Code: [Select]

ch = Metashape.app.document.chunk
for i in range (len(ch.cameras)):
    ch.cameras[i].photo.path = ch.cameras[i].photo.path.replace(".tif", ".jpg")


74

Feature Requests / Re: Standard Plus (i.e. Medium) version please!

« on: April 11, 2022, 10:50:22 PM »

I've been learning Metashape Pro using the trial version to create georeferenced 3D models from drone photos. Only 9 days left on my trial and then I can't do it anymore! I'm modeling coastline landscapes and historic sites in Hawai'i on my own time, not commercially. Unfortunately the high price of the Pro version needed for georeferencing/GPS makes it unattainable. After my trial ends I'm going to try RealityCapture, but from what I've seen it's not as good as Agisoft

75

General / Re: Bad texture issue

« on: April 11, 2022, 09:30:18 PM »

I'm learning drone 3D mapping and I've observed this issue. Agisoft chooses the photo closest to every given location geographically,  at least for creating the orthophoto. Since I mix higher and lower altitude photos, the higher ones often get chosen so I get blurry patches. I have to manually draw a polygon and then choose a different photo for that area. Disabling the more distant photos works, but not if you need parts of those images for coverage elsewhere in the model