Bill VS

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Bill VS last won the day on August 25 2019

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  1. Thanks Harry, for your perspective and counsel! I have the RTK ground control and markers, and am much closer now to a solution after adjusting the altitude. I'm also very fortunate to have a survey benchmark visible on the imagery to use as a checkpoint. I'm going to have to develop some serious Pix4D muscles to get within my intended accuracy of an inch or so, but I hope to get it done next week. Do you happen to know how best to share the resulting product to someone who uses AutoCAD Civil 3D?
  2. I have good news! I went out and flew a test mission straight up and down, capturing images at 0, 50, 100,... 400, 375, 325, 275, etc., to get relative and absolute elevation values every 25', ascending and descending. Used Exiftools to export the metatags from the imagery, and... the problem is linear (r-squared equals 1!) , and the units are indeed in meters: Apparently DJI uses a weird ellipsoid (model of the earth's surface) in their calculations, so in my area, the elevations are 70.5 m (231.4') below what they should be. That explains why the UAV thought it was belo
  3. Hey all, thanks so much for responding to this post. My ability to spend time on the project waxes and wains due to higher priority stuff, but I think I'll be able to get back on it pretty soon. CaseyC reached out, so I'm going to provide them some info soon, but I'll cc this post if you guys would like more nuts n bolts. Just to clarify, here are some bullet points to clarify the error we're talking about here: By my calculation, the GPS units that DJI is recording (on both the Phantom and the Inspire) are 1 unit equals about 50', so that's going to account for a pretty huge differ
  4. Hey Nadine and Casey! It's good to hear from both of you! It's also good to hear I'm not the Lone Ranger regarding the vertical error problem. We placed and surveyed a dozen survey targets on the Lake Apopka Levee at the time of flight, so I have GCP data. The problem is that Pix4D doesn't seem to accept the GCP input, either in "automagic" mode or manual edit. And the folks at Pix4D are little or no help. If you have Pix4D and Skype, could we set a time this week or next to share my screen and go through the steps together?
  5. Can anyone advise me about the problem with vertical GPS values on DJI units? The horizontal values seem to be just fine. We have an Inspire 1 and an Phantom 4 Pro. We have been using them, along with DroneDeploy and Pix4D, to map wetland vegetation for wetland restoration projects in Florida. The problem arose when we started combining imagery with survey to create and deliver 3D models to our engineering colleagues. Both UAVs report accurate altitude to the RC, but the EXIF tags tell an entirely different story: A photo taken at ground level (let's say, 65' above sea level),
  6. If you're talking about reading sectional charts, the purpose is for you as a commercial remote operator to find out where you're not allowed to fly. I've learned that, since we have to yield right of way to all manned aircraft, I still spend lots of time dropping the drone and burning battery time near the deck as someone in a Cessna loiters over the marsh at a few hundred feet, doing lazy turns and maneuvers and just enjoying the low-density air coming off all that warm water. I put in NOTAMs, I contact all the local airports and warn them, and still I get the little single-props and se
  7. I suspect that EPA will be a bit shy about "surveilling" private property with UAVs. They've gone all the way to the Supreme Court with high altitude aerial imagery, but that doesn't mean they want to do it again over drones. My guess is that they'll likely stick with satellite imagery for large scale monitoring, and go to the state regulatory agency and/or contractors for local monitoring, SuperFund compliance, etc. BLM and USACE, on the other hand, appear using the heck out of drones, as are some of the state Department of Natural Resources agencies. At the State level, Florida has bee
  8. I don't know the answer to that question yet, but I suspect it will be a moving target, depending on 1) what our annual mission backlog starts to look like as we get more requests from internal clients, 2) The features and prices offered in the marketplace over the coming years and 3) what our management is willing to support with budget resources. Right now, we have a Phantom 4 Pro and an Inspire 1. Long term, I suspect a VTOL system may do a better job, but for now, we have what we need in order to figure out what we're gonna need. I haven't flown the Phantom yet (it's stationed in
  9. Guys, as a GIS/IT/Environmental Sciences professional who uses sUAVs, I want to say that I agree with and appreciate what I'm hearing from you guys! This stuff belongs on its own FAQ page. Well done. The only thing I might add is that 1) getting part 107 certificated is a pretty good/easy/inexpensive place to start, if you haven't done that already (obvious, but worth mentioning?) 2) I would check in with the Army Corps of Engineers (they're doing lots of LiDAR and storm damage assessment work with drones these days). Also, what about Border Patrol? Who wouldn't expect those guys to be u