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61
General / Re: Trouble with UAV & Local Coordinate System Workflow
« Last post by Paulo on July 20, 2021, 01:53:00 PM »
Hello again Super,

I have some thought on a different way to tackle your problem. If your client does not require the outputs to be in their local CS, you coud process the 2 datasets in 2 different chunks with Coordinate system defined as WGS84. After marking the GCPs in the 2 datasets (with no need to import the Local GCP coordinates), check all cameras and uncheck all markers and do Update Transform.

You will get the GCPS in 2 datasets with estimated coordinates in WGS84. Next align the 2 chunks using marker based method and voila you will get the 2 chunks aligned in same datum and you can fill gap...
of course, this way your products will have a relative high WGS84 datum accuracy but absolute accuracy will be a few meters because of low accuracy of camera GPS coordinates...

Additionally you will now have the the GCPs coordinates in the local CS and WGS84 which could help you define a datum transformation between the 2...

Hope this makes some sense,
62
General / Re: Trouble with UAV & Local Coordinate System Workflow
« Last post by Paulo on July 20, 2021, 08:14:58 AM »
In the reference pane, select all your images or cameras and in right click context menu, you will find Clear... which will open Clear Reference menu where you select Location option to clear all cameras reference locations....

Is 65% the forward or side overlap? It is best to have at least 60% side lap and 75% front lap but less can also be dealt with if there is good texture in imagery which seems to be your case as from camera coordinates you are on a mining site, right?
63
General / Re: Trouble with UAV & Local Coordinate System Workflow
« Last post by Super_Saffer on July 20, 2021, 06:52:13 AM »
Do you mean "reset camera alignment"? I don't see an option to remove the camera reference from a right click menu, but rather the reset camera alignment option.

I learned this evening that the overlap was only 65%, so I'm not sure how much of an issue that it.
64
General / Re: Trouble with UAV & Local Coordinate System Workflow
« Last post by Paulo on July 20, 2021, 06:30:53 AM »
Hey Super,

yes you must clear camera  references  `cause they refer to WGS84 datum and your GCPs are referenced in some local CS with unknown datum transformation to WGS84. So if you keep the camera references you will get some error message as
Quote
Unsupported datum transformation
.....

15 GCPs is sufficient to reference your projects. Maybe use 10 as GCP and 5 as Check points (unchecked during optimization).
65
General / Re: Trouble with UAV & Local Coordinate System Workflow
« Last post by Super_Saffer on July 20, 2021, 05:35:43 AM »
Thank you Paul!

If there is not a GCP in every photo do I still want to remove the camera references? It is a very large area, and over 1000 photos, but only very few with GCP.


Hi Super Saffer,

I think what you need to do after importing the GCPs in local coodinate system, is open the Reference settings (with tools button) and define the coordinate system as local, uncheck the camera reference option and set marker reference as Local CS as in attached screen copy.
Then deselect all your cameras, clear all reference camera locations (with right click context menu) and mark the GCPS in each photo, Update Transform and you will now have the model referenced in local system.

In example shown, my original project was referenced from cameras in WGS84. I imported 3 GCPS in local CS and defined the various CSs in reference settings. After marking the GCPS in at leat 2 photos each, i update my transform and now the model is referenced in local CS (X, Y in 100 s instead of lat, long....)

Hope this makes sense,

PS. it seems definitely that the GCPs local z is in feet as it is 3 times larger than camera reference altitude....
66
General / Re: volume measurement without gcps
« Last post by Apavlicek on July 19, 2021, 10:02:32 PM »
I got it figured out. I was drawing a polyline instead of a polygon around the object. thanks again
67
General / Re: volume measurement without gcps
« Last post by Apavlicek on July 19, 2021, 09:51:37 PM »
Thank you for the reply. Maybe im selecting the wrong option during the workflow to create the dem. Im unable to click on the volume button.  it is greyed out like it isnt available
68
General / Re: volume measurement without gcps
« Last post by Paulo on July 19, 2021, 09:31:29 PM »
AS ong as your project is georeferenced then it will be possible to measure the volume... as you can see I put a shape on DEM for a project without GCP only referenced with camera center GPS coordinates and volume can be measured....of course it may not be as precise as with GCPs, but if model  is correctly leveled and scaled  then difference should not be very big...

69
General / volume measurement without gcps
« Last post by Apavlicek on July 19, 2021, 08:35:50 PM »
Is it possible to measure volume without using gcps. The photos of the stockpile were collected with a dji phantom 4pro. Is there a workflow that will allow you to measure a stockpile without using gcps?  Ive never used agisoft to measure volume before and i wanted to compare the difference with and without gcps. I have been unable to make it work yet though. The dem has already been created for the model without gcps. When i attempt to measure the shape in the dem only planar and profile are available. The volume button is grayed out and i can click it.
70
General / Dense Cloud avalanche point errors
« Last post by jetdog6 on July 19, 2021, 07:06:25 PM »
Hi, I've been using metashape for aerial photogrammetry for years now.  A recent job is showing really weird errors in the dense cloud that look like avalanches almost.  It's like at a single point the error started, and then flows downhill in a triangle shape.  It's only visible when using the classify ground function.  it's also visible in the DEM as a sort of triangle shaped depression.  Because of their shape, I think it's a program error.  I'm running 1.7.3.12473.  Thanks for the help.
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