We are currently experimenting with drone data in house.?ÿ?ÿ
Our drone is storing coordinate data in WGS but our GCP data we have been collecting in SPC.?ÿ ?ÿ
We can convert the SPC to WGS or next time we can just locate in WGS.?ÿ Ultimately I would like the deliverable to be in SPC.
I am wondering peoples thoughts and process how they deal with this.?ÿ If I enter my GCPs in SPC will it just align and convert my ortho to the spc coordinate system??ÿ Or do I need to have both photos/gcp's in the same system prior to processing?
We are currently experimenting with drone data in house.?ÿ?ÿ
Our drone is storing coordinate data in WGS but our GCP data we have been collecting in SPC.?ÿ ?ÿ
We can convert the SPC to WGS or next time we can just locate in WGS.?ÿ Ultimately I would like the deliverable to be in SPC.
I am wondering peoples thoughts and process how they deal with this.?ÿ If I enter my GCPs in SPC will it just align and convert my ortho to the spc coordinate system??ÿ Or do I need to have both photos/gcp's in the same system prior to processing?
Are you sure that the drone data is "WGS?"
Where/how is the drone getting its corrections, surely it isn't returning autonomous positions (is it)?
LOTS of post processing software?ÿdisplay/print "WGS84," even when?ÿYOU input NAD83, therefore "forcing" the solution into NAD83 (both ends, despite what the printout may say).
Inasmuch as each vector solution is expressed in the same datum as the ephemeris used in processing, the scale/rotation issues between WGS84, IGS08/14, and NAD83 are generally a trivial issue on SHORT vectors (like RTK). However,?ÿwhen one is solving "long" vectors, mixing datums can be an issue. This is the reason that OPUS does everything?ÿin IGS/ITRF, and doesn't transform things to NAD83 until all of the heavy lifting is completed.?ÿ?ÿ?ÿ
Loyal
Are you using Pix4d?
In Pix4d you assign the input coordinates to WGS84 metric. The output coordinates would be SPC USft with the Geoid separation manually assigned.
My understanding is that all GPS systems collect WGS information and the person decides what other system they are wanting the final data and the hand collector will output in that form.
I use GNSS program and when I take my collected data and select a datum and geoid, the results will be translated into that form.
A picky point, but one that may improve clarity:
SPC is a projection that can be calculated to or from latitude and longitude.?ÿ Another projection is UTM, and there are many others.
The lat-lon can be relative to any of various datums such as IGS/ITRF, WGS84, or NAD83.
SPC usually is associated with NAD83, but they are different kinds of thing and both should be specified to be entirely correct.
Meters, US sFt, and iFt are another choice, and it is possible to have SPC in any units, although most states define which is official.
Thank you for the many responses
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To clarify, we dont have a program we use yet.?ÿ ?ÿRight now we have a free trials including pix4d.?ÿ ?ÿThe program is seeming to fail so we didnt know if the coordinates difference is the problem.?ÿ ?ÿ
Thank you Bill.?ÿ Yes my SPC coordinates are in NAD83.?ÿ ?ÿ?ÿ
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Lee green may have nailed it.?ÿ My SPCs are in sFT, my drone is native to metric.?ÿ ?ÿWe may be setting pix4d with the wrong systems hence why it is showing up on the wrong continent.
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Thanks for all feedback.?ÿ I will make some adjustments and go from there.?ÿ ?ÿKeep you posted!?ÿ
The drone I would assume is collecting positions autonomously.?ÿ It's just standard photo coordinates from the drones on board gps.?ÿ ?ÿThis isnt RTK, just your normal DJI drone.?ÿ?ÿ
Yes, as harris said, my collector is probably collecting in whatever is native, but I have the projection set to SPC so it displays the results in SPC, I can display those in whatever projection or system so getting the coordinates now in any needed form is no issue.?ÿ?ÿ
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Thank you for the many responses
?ÿ
To clarify, we dont have a program we use yet.?ÿ ?ÿRight now we have a free trials including pix4d.?ÿ ?ÿThe program is seeming to fail so we didnt know if the coordinates difference is the problem.?ÿ ?ÿ
Thank you Bill.?ÿ Yes my SPC coordinates are in NAD83.?ÿ ?ÿ?ÿ
?ÿ
Lee green may have nailed it.?ÿ My SPCs are in sFT, my drone is native to metric.?ÿ ?ÿWe may be setting pix4d with the wrong systems hence why it is showing up on the wrong continent.
?ÿ
Thanks for all feedback.?ÿ I will make some adjustments and go from there.?ÿ ?ÿKeep you posted!?ÿ
The drone I would assume is collecting positions autonomously.?ÿ It's just standard photo coordinates from the drones on board gps.?ÿ ?ÿThis isnt RTK, just your normal DJI drone.?ÿ?ÿ
Yes, as harris said, my collector is probably collecting in whatever is native, but I have the projection set to SPC so it displays the results in SPC, I can display those in whatever projection or system so getting the coordinates now in any needed form is no issue.?ÿ?ÿ
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Pix4d makes it a bit confusing by requiring the end user to define the input datum from pictures created by the drone. The software should know by default the drone model that the input is always metric WGS84 Lat, Lon, Ellip. Then the output coordinates are user defined as cartesian coordinates Y,X,Z in USft for most US projects. The software does try to identify the SPC zone, but often gets it wrong.
In Pix4dD the import of the images with be WGS. You can select the output coordinates to whatever system you want. Pix4D won't "fail" - I assume you are selecting ( assigning) the pictures to NAD83 on the import, which is causing your error.?ÿ
I am compiling for an upcoming presentation the datum handling transoformations inside popular software engines.?ÿ I do not own Pix4D, so this is an area of weakness.?ÿ Can anyone tell me specifically, what transformation is the DEFAULT "WGS84-NAD83" transform embedded in Pix4D.?ÿ Are there options to change the DEFAULT, and if so, what datum transformations are available.?ÿ If this could be done with a screen grab, that would be great, but I'm really interested in the actual parameters (3 or 7) if they are exposed.?ÿ ?ÿThe name of the transform is just as important, since software companies use a variety of names.?ÿ For example, Pathfinder Office or Trimble Business Center calls the NULL transform NAD83(CONUS) or NAD83(Alaska). Exposing the Coordinate System library does expose the parameters 0,0,0.
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thanks - You'll get credit on a slide at the upcoming www.aksmc.org conference in Alaska (Feb 13-17).
JOel
Update #2
I used carlson's photogrammetry online software and it worked like butter.
It only asked my GCP datum and what I wanted my output datum to be.?ÿ ?ÿNo errors.?ÿ ?ÿGave a very nice looking ortho and point cloud.?ÿ ?ÿGCPs solved good and were a snap to do.?ÿ?ÿ
Now to go back and try Pix4d again, a few others, and then to sample test the processed results.?ÿ?ÿ
Rich,
So following your thread, you ingested GCP's in NAD83 (2011) epoch 2010.0.?ÿ Your raw autonomous data in "WGS84" or IGS08 (if WAAS). You assigned photos as WGS84, then selected output datum/CS.?ÿ What datum was selected, and if you can, provide the parameters for the shifter used??ÿ?ÿ
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Tx.
With Pix4D, most of the time, I'm in an arbitrary coordinate system and when I sent up the project, I indicate that I am using an arbitrary coordinate system, in feet. I generally don't really care what coordinate world Pix4D seems to think it's in, generally it's in the correct system though. I will use that selection even when I am using "SPC" coordinates, it seems to help Pix4D to not use a specific coordinate system. I will then tie the GCP's to the photos and then start my initial processing. In the end Pix4D will produce both a TFW and PRJ file that accompanies the output aerial photo. The PRJ file is used with some programs (i.e. ArcGIS) and the TFW file is needed for other programs (i.e. AutoCAD or Carlson). With either file, it will place the photo and contours in the desired projection/coordinate world.
Andrew,?ÿ
Excellent.?ÿ If its not too much trouble, could you copy/paste the contents of an example PRJ (associate?ÿ .prj with any text editor), so I could verify the PRJ meets ArcGIS projection library syntax??ÿ You wrote in the 5th sentence "In the end Pix4D will produce both a TFW and PRJ file...".?ÿ Does this mean Pix4D automatically senses the SPC coordinates including zone internally via a zonal envelope, or is there an assignment step that you tell Pix4D "im in SPC XXZoneXX"??ÿ Finally, is there any opportunity to assign the datum tag of NAD83_2011 when assigning "NAD83" as output datum??ÿ ?ÿThis will be very useful for me.?ÿ I'm conducting the same sequence in the AGISOFT world that our team uses.?ÿ?ÿ
Thanks.?ÿ ?ÿReply if you concur that I use your profile name or any other Name/Title in the credits to this slide (or not).?ÿ?ÿ
Joel
Joel,
Here is an example of a PRJ file that Pix4D created. This particular example is a project that was done in state plane (OPUS session) but is still using an arbitrary system:
LOCAL_CS["Arbitrary (ft)",LOCAL_DATUM["Arbitrary datum"],UNIT["foot",0.3048,AUTHORITY["EPSG","9002"]]]
Let me know if this helps.
Thanks, Andrew
