Topics

1

General / Possible Reprojection Issue in v 1.8.0

« on: January 17, 2022, 08:27:15 AM »

Hello,

I’m running an orthorectification script which orthorectifies a selection of photos in the UTM coordinate system defined in the project and then exports the orthomosaic in a different (neighboring UTM) coordinate reference system.  This script was run in headless mode on MacOS and I am now attempting to replicate through the GUI, although it's slow going as I mention below with relation to the estimation of tile boundaries. Still I did notice that in the console with the GUI the buildOrthomosaic line prints “projection = NAD83 / UTM zone 5N”

I believe I have the projection defined properly in the script, however in headless mode the script does not print the projection in the terminal per this pertinent section of the script as it does in the GUI.

projection = Metashape.OrthoProjection()
projection.type = Metashape.OrthoProjection.Type.Planar
chunk.buildOrthomosaic(surface_data=Metashape.ElevationData, blending_mode = Metashape.MosaicBlending, fill_holes = True, ghosting_filter = False, refine_seamlines = False, resolution_x=1.0,resolution_y=1.0, projection = projection)

Instead, it prints the following to the terminal without the projection information, although I think it's still creating the orthomosaic in the defined project coordinate system.

BuildOrthomosaic: surface = DEM, blending mode = Mosaic, refine seamlines = 0, ghosting filter = 0, pixel size = 1 x 1

After the orthomosaic is built at the end of the script is an exportRaster statement that reprojects the data to the neighboring UTM zone on export to GeoTIFF.

v_projection=Metashape.CoordinateSystem('EPSG::26906')
projection = Metashape.OrthoProjection()
projection.crs=v_projection
chunk.exportRaster(path = pathOrtho, projection = projection, source_data=Metashape.OrthomosaicData, image_compression = compression, resolution_x=1.0,resolution_y=1.0, save_alpha=True, white_background=False)

In the terminal the operation seems to be performing the proper operation as expected with ExprotRaster reporting the proper projection however with a shift in the exported result.

projection = NAD83 / UTM zone 6N, resolution_x = 1, resolution_y = 1, white_background = off

The script seemed to work well in v1.7.5, however, now that I have upgraded to v1.8.0 the reprojection does not appear to provide the same result and instead appears to introduce a shift from where it should be and where the orthomosaic had been positioned appropriately in previous iterations of the script.  I don’t know if something may have changed in the api with regard to this reprojection issue or the version.  I also tried going back to 1.7.5, however, it looks like that version is also now yielding the same shifted reprojection results as generated with the upgrade to v1.8.0.  I thought I had read something in the 1.8 pre-release post about backwards compatibility issues from 1.8.0 back to 1.7x but I’m not sure about that.  I also notice that this can take an exceedingly long time (many hours) to “estimate tile boundaries” which I know is a separate issue.

Any guidance or advice about this reprojection issue would be appreciated.

Thank you.

Rob

2

General / reimported DEM - introducing error in orthomosaic

« on: January 31, 2021, 12:52:48 AM »

Hello,

I'm trying to understand what I may be doing wrong or why I'm getting different results in terms of positional accuracy of an orthophoto mosaic when:

A) an orthomosaic is generated in a project (A) from a DEM developed from dense point cloud, compared to

B) the same orthomosaic is generated from DEM exported from project A) and reimported into a copy (project B) of the original project A)

The orthomosaic generated in project B) is using the DEM exported from project A, and appears to introduce about 11 meters offset in the resulting orthomosaic which happens to be the approximate resolution of the DEM exported from project A.

Has anyone encountered a similar issue and what recommendations might be available to replicate the original project A's orthomosaic positional accuracy in project B with the DEM reimported into project B?  I would expect that the orthomosaic from project B using the DEM from project A should be identical.

Thank you.

Robert
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3

General / Marker measurements lost in version 1.3.2

« on: June 01, 2017, 08:33:13 PM »

Hello,

I recently installed 1.3.2 and opened a project created and saved in 1.3.1 (4030).  Upon opening, the project in 1.3.2, most of the markers did not show their corresponding measurements and those that did show only related to two ray point measurements.  Then I went back to version 1.3.1 and opened the project and all the measurements appear as normal.  I'm not certain what might be the cause of this behavior in 1.3.2.

Thank you for your assistance.

Robert
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4

Bug Reports / Reconstructing depth...99%

« on: October 11, 2016, 03:54:15 PM »

Hello,

Over the weekend I processed a project (in v1.2.6) that appeared to be going well during the dense point cloud processing.  The reconstructing depth process reached 99% and then I let it continue there for about 24 hours.  It did not appear to be doing anything, so I canceled the process and removed some excess photos.  After removing those photos I started the dense point cloud processing again with the same parameters (medium/aggressive) and now this morning the reconstructing depth process has arrived at 99% again and has not changed status over the past two hours.  I'm just wondering how long I should let this process continue or should I be trying another strategy to get this to complete the dense point cloud processing.  Everything on the system appears fine and I'm attaching a copy of the partial console log (the beginning) as the full log currently (at 3+MB) exceeds the attachment size limit.  Thanks for any recommendations. 

Rob