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Messages - Geo

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1
General / Re: How to treat Weights in alignment and optimization
« on: July 06, 2017, 05:59:48 AM »
Hello Sav - Thank you so much for your detailed solution.  I will try this tomorrow.  That's great to know about the coordinate conversion utility - makes sense to have that.  I will have to monitor the forum more often and keep up with changes.  I use 1/8 inch thick white styrene targets that I can auto identify which works great.  I use a jumbo marker to make the black pattern on the target that really lasts compared to paint.  I may have a question about the gradual selection process - I have read Geert's instruction on that, but it seemed cryptic to me.  I will review that and give it a try. Thanks again SAV - much appreciated. :)

2
General / Re: How to treat Weights in alignment and optimization
« on: July 06, 2017, 01:56:25 AM »
This example may help see the issue - see attachments.  Control coordinate input was double checked.  The camera position accuracy is about 2 to 3 metres as expected.  The photo network design is fine with good forward overlap and sidelap with coverage both in a N/S and E/W west double coverage pattern. :'(

3
General / How to treat Weights in alignment and optimization
« on: July 06, 2017, 01:24:46 AM »
Greetings - I would like a final model output using UTM coordinates.  The camera exif coordinates are in geographic.  My workflow is that I load the images and do an alignment  on low accuracy with the autonomous coordinates (Lat and Long).  I then export a camera xml file and then do a conversion to my UTM coordinates and then import them back into the project.  I then seed my accurate target coordinates, uncheck the photo coordinates and run the alignment in medium or high accuracy depending on how many photos there are. Then I do an optimization with only target marker coordinates checked and a rolling shutter correction.  This generally seems to work very well.  Ground checks confirmed this.

The weight for the camera coordinates is 10 metres and the weight for the target coordinates is 0.005 metres.  After the adjustment, the camera coordinates seem to be generally within a few metres as I would suspect and the accuracy of the target coordinates is very good as suspected.

I am wondering how the adjustment treats these weighted coordinates? Is the above workflow appropriate?  Or should I leave the camera location coordinates checked on with the 10m weighting?

I used to run the projects with only the target coordinates checked on, however, I found that often many of the cameras would not align unless I did the process outlined above.  I just did a nest of projects and I am having difficulty in getting the good adjustment/alignment accuracy that I normally have.  Not sure what to do? - deadlines for the data are now.

4
General / Re: Agisoft PhotoScan 1.3.0 pre-release
« on: November 25, 2016, 02:51:13 PM »
Hello Alexey - I used the rolling shutter function (worked perfectly) and I started another project and I receive a license error notification box.  The release mostly still works except some functions are shut out.  I desperately have to complete another project.  I am using a windows based system.  Is there a new pre-release version that does not have this issue.  I downloaded the pre-release version from the link in the first thread note.  Is there a location to download the latest pe-release version?

Thank you,
Jim

5
General / Re: Generate true orthophoto from Agisoft
« on: December 02, 2015, 10:48:52 PM »
This is very impressive.  I commend you on this enhancement and the tool is very functional and visual and flexible.  It must have been a great deal of work to create this.

I would like to point out that the update version message is not functioning properly.  I look at my version of Agisoft Photoscan Pro and it tells me I have the latest version which was not version 2.  This is why I initially could not find the tool.

6
General / Re: Generate true orthophoto from Agisoft
« on: December 01, 2015, 02:01:24 AM »
Thank you Alexey for identifying the seamline editing link.  I read the section in the manual, however, I am having trouble finding the tools mentioned.   Firstly, you mention open in the "Ortho View" in your forum note above.  I am not sure what you mean by ortho view toolbar.  I do not seem to see the "Seamlines" button in the normal Toolbar menu?  Maybe I am missing where you get to "Ortho View".  This is quite important to me to master as my sites often have vertical man-made surfaces.  In order to try to map these portions, I take  a standard set of forward overlapping (80%)/Side-lapping (60%) photos and a second set of oblique images in a cross-convergent pattern at a 20 degree tilt from the nadir and also some oblique orbit photos to attain a good set of imagery to map these surfaces.  I would like to maximize the result of the orthophoto.  Thank you

7
General / Large data set Alignment Tips
« on: October 08, 2015, 11:23:57 PM »
I have about a 1000 aerial photos taken with a UAV at about 50m AGL in a near nadir view.  The photos do not have geo-referencing.  I am having trouble with alignment.  There are some large areas (100 photos or so) that do not align.  As this is a large dataset, I don't want to have to run the project trying various settings as it will take a long time on my computer.   Can you recommend what alignment settings would be best to have the best chance of initial alignment.

Which settings would you recommend:

Accuracy:  high, medium or low  ( I set medium)
Pair Selection:  generic, pair selection or reference  (I set generic)
Key Point limit:  default  (40000 I think)
Tie point limit:  default (1000 I think)

And are there any other tricks to help obtain an alignment?  For example can you manually set tie points to help alignment? etc.



8
General / Point Cloud from Cropped Model
« on: September 26, 2015, 08:11:19 PM »
Hello to all - I cropped my model in Photoscan and exported a LAS point cloud.  When I view the cloud in Cloud Compare it has points for the whole original model.  How do I create a point cloud of just the cropped model?

9
General / Clone of eBee type aerial wing platform
« on: June 13, 2015, 09:52:56 PM »
I am hoping someone can provide a link to an aerial wing similar or equivalent to an eBee type aircraft that will perform in fairly high wind conditions.  I am hoping there is a supplier that has put together a clone of the eBee/Trimble UX5 type aircraft in a kit form or almost ready to fly setup.  Any recommendations would be appreciated.  I will want to be able to use an automated flight system like the PixHawk or equivalent.  I will of course process using Agisoft.  Thank you in advance.

10
General / Re: dji vision camera
« on: June 10, 2015, 07:22:32 PM »
Hello Mortar,  I finally tested the DJI Phantom 2 Vision Plus.  I am having trouble modeling the near vertical imagery in Photoscan.  Not all photos align.  I may need to have better side-lap and perhaps forward overlap.  I will keep testing.  I am wondering if you have any other tips for processing the DJI imagery for modeling.  Would it be best to just use the HD video recording and extract frames for good overlap so that there is more data if needed?

It may be best to mount a small Canon camera for the mapping and use the Vision Camera for visual documentation (aerial panoramas, oblique stills and video).

I also bought the DJI Phantom 3 and the imagery seems very good and models well (95 degree FOV).

11
General / Re: NVidia Quadro 4000
« on: May 23, 2015, 05:33:01 PM »
Thank you for your reply.  Would IT be able to install both cards to work?

12
General / NVidia Quadro 4000
« on: May 23, 2015, 02:36:59 AM »
We have a HPZ400 workstation that has 16gb RAM and I believe has an NVidia GeForce GTX 760 card in it.  I asked our IT department for an upgrade to at least 64gb of RAM for processing imagery in Agisoft.  They have another workstation that is a HPZ420 that they are going to build and swap out for the old one.  I mentioned to IT that a new SSD  that was recently installed in the old workstation and would be very helpful to have in the new workstation and that the NVidia GeForce GTX 760 card or better from the old machine is also critical for the processing.

IT replied that they will put in a good SSD and a Nvidia Quadro 4000 video card.  Can someone please let me know if the Quadro 4000 is better that the GeForce GTX 760 card?

13
General / Re: Archaeological Planning using Photoscan- without GC
« on: March 25, 2015, 11:30:19 PM »
Hello Hugh,

You may want to consider the following tools for your type of project.
1) use a small 30metre steel tape in a rolling winder (approx. cost $30) to create scale lines for your project.  Depending on the scope of your project, you could typically layout three control markers on a straight line with your tape.  Then create two other control markers by using the mid marker and each end marker by setting two markers on one side of the 3marker line.  Tape the distance from the end marker and the mid marker to the two point outward from the 3point line.  These are the distance observations for scale.

2) Use a second hand builders level (very inexpensive) and a surveyors rod to measure relative elevations of all five markers. These are the elevation difference observations.

3) use a hand held GPS (everyone has one right) to record averaged positions (N,E) for the five control markers.  These are the coordinate observations.

4) If you set out the three points on line properly carefully, then you have an angular observation being 180 degrees at the midpoint

5) Enter your observation data in the excellent free Gama Least Square adjustment program by Ales Cepek and team.  Use the appropriate standard deviations for the observations.  For example for the 180 angle observation use "0" seconds thereby fixing the straight line. Maybe use one centimeter for the distance and the elevation difference observations.  Use two to ten metres for the standard deviation of the autonomous GPS.  You will first run a separate vertical adjustment with the elevation difference observations and thereby obtain adjusted elevations and have a check on the quality of the observations.  Secondly you will run the horizontal adjustment.  The Gama least square adjustment will respect the weighting that you used and provide final real world coordinates and relative accuracies.  You could even add in forward and reverse compass azimuths with say a standard deviation of about 2 degrees, but not needed.  The adjustment will show you how good your autonomous GPS observations as are as well. I think typically around the 2 metre absolute positioning level and Gama will make the distance observation best fit the GPS positions of course.

6) When you add the control points in and run Agisoft, the result will of course show how well the control fit the photo alignment/mesh which provides another indication of the accuracy of the input scale measurements. 

This may seem overly complex to do, but once you have the abstract format understood, it is very quick to do for these small networks and very rigorous way t do it.

Gnu Gama can be found here:  http://www.gnu.org/software/gama/
I am not sure whether this user interface for Gama up to date and working
http://roci.sourceforge.net/

I created a little resource site about ten or fifteen years ago that has some sample input file and resource info on using Gama
http://vrmapper.com/gama/gama.html

There should be sample horizontal and vertical input files that you can simply use and fill in your own data.  There is an instruction on how to install and run Gama as well.  It is a very good/powerful and easy program to use once you complete your first project.  I think it is ideal for use on small archaeological or similar sites.

I hope this helps,
Jim

14
General / Re: dji vision camera
« on: March 06, 2015, 04:09:02 AM »
Thank you for the info - much appreciated.  I decided to purchase the Vision 2 Plus V3.  Can't wait to test

15
General / Re: dji vision camera
« on: March 03, 2015, 07:31:17 AM »
Hello to all - I am thinking about buying a DJI Phantom 2 Vision Plus (V3.0) for flying small facility sites about 150m by 150m size.  I have a couple of questions for those that are using this rig.
 
1) It sounds like the vision 2 plus camera works Ok for modeling in Photoscan, however, how do you take photos every few seconds as it sound like it is a manual camera trigger from the smart phone app?

2) I am wondering if it is feasible to add a 150gm Canon compact camera running CHDK intervalometer script to the frame as well for taking the actual mapping imagery?  Will it handle the extra 150gm's?  If not, how easy is it to take off the vision camera gimbal to then be able to mount the Canon camera?  Would it be easy to take the vision gimbal on and off?

Please enlighten me - Thank you :)

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