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43 comments
Without seeing the screens shots it's hard to say.
GPS can be off by about 16ft if not using rtk.
But we're you using the GPS position to calculate? Maybe it's not showing enough decimal places to be accurate enough for you?
Above are the 3 screen shots labeled for what was used to measure. "Home" is the base of measurement and then the 2 items measured to was the corner of a soccer ball net and a trailer. I could only physically check the trailer with a 100 foot tape because there was an undisturbed line between home and trailer. I just today checked with google earth and it also said 107 feet like the laser. I used the following standard calculation known as the "Pythagorean theoream". I used 2 different methods to get the GPS Coordinates, one was the Dronelink program and the other was an app called live mobile app that uses your phone to check GPS location. Both measurements came out exactly the same 160.34 feet. That's a difference of approximately 57 feet. My research on the formula says there is no difference if you swap the location of the Latitude and Longitude in the formula, although I have not tried it yet. I have only done the calculations between home and trailer because it is an unimpeded shot between the two. For the shot on the soccer net I have to take a distance shot from home to a fence which is between the two and then a shot from the net to the fence and then add the two shots. Pretty accurate but I have no physical way like a tape measure to confirm. So the formula says to subtract the longitude from the latitude (or vice a versa) for both locations then square both results and add them together and then get Pi of the result. Try it tell me what you get.
Found this video on you tube that explains how to calculate it
https://www.youtube.com/watch?v=LqNMvXDjZWk&t=209s
The guy is writing a computer program to calculate it for you. Too complicated for me.
Its just an Excel spreadsheet the first way he does it
Here's an online calculator that uses a precise formula.
(The formula you are trying to use, the equirectangular approximation, is also down that page a bit, but it is only an approximation -- for precision, you need spherical geometry instead of plane geometry -- but you don't have it quite right, anyway. You wanted to subtract one longitude from the other and multiply by the cosine of the latitude, subtract one latitude from the other, use the Pythagorean theorem on those two numbers, then multiply that result by the radius of the Earth.)
I tried that calculator, it worked somewhat. These are the cooridnates between two points according to the drone.
42.232515 -71.146025 and 42.232210 -71.145916. I physically measured with 2 items, one a laser measurer and a 100 ft. tape. The tape said 105 feet and the laser said 107 feet (laser is extremely accurate). The program you sent me said 115 feet, closest yet, but the drone says 64 feet. I have used several programs through my phone that give me the coordinates and so far everyone one gives different coordinates. One said the distance between coordinates was 1/2 mile. This is driving me nuts, why are there so many different results? I am going to go out tomorrow and try some more experimenting.
Where does the drone say 64 feet? I don't quite understand what you're doing here -- is that the D shown if you launch from that first point and fly to the second?
Did you try setting the distance reference to Home in the latest beta?
Roger you know I never even looked at that, I was concerned with the Lat. and Long. That makes it even more strange because the distance from where I flew, my launch pad, to my trailer, where that screenshot was made is a hand measured 107 feet. You can see the corner of the trailer. The screenshot before that one is the corner of a soccer net, as measured with a laser it is 273 feet. You can see the corner of the net in the picture and you can see it says distance 5.5 feet.
Maybe Jim has an answer to this dilemma? I did not know there was a way to set the distance. Can you explain Jim. I will try some more tests today.
Ok, I just did 2 tests. The first one was with Dronelink. I launched from my pad (white square) and already DL has the wrong distance, it's saying 24 feet. I fly to the trailer, 107 measured feet, and hover above the location of measurement, and it says 19 feet.
Second test I launched with DJI and it said 1.8 feet. I flew to trailer and hover above the location of measurement and it said 105 feet (real close), this I can accept.
I tested with DL modern I am going to try Classic.
I will use Rogers site for measuring and see what it says
Oops forgot to send screen recordings
I ran the coordinates generated by DL and it came out to a distance of .02951 km this converts to 96.818 feet. Can't do DJI because they do not show coordinates, I don't think.
My screen does not look like that.
According to "Play store it is already installed, v4 right?
Bob Scheffler, you need to click on the settings tab, rrather than the drone tab to see the same as Jim McAndrew is showing in his screenshot
I tried downloading and I get an error msg. from Dronelink "App not installed as package conflicts with an existing package. Only choice now is "Done".
I did, as you can see from my screenshot I am in the same area but I do not have the same options. Jim says I have to do an update, but I followed your links and it said as above there is a conflict. I have version 4.0.0(219) Kernel 4.0.0
the settings tab is the one with a folder and gear wheel, one to the left of the tab you show in your last screenshot
This one,
I see nothing there about distance reference. Even if I did have that I don't think that allows me to change the footage reported. As shown in previous screenshots I am at home base and the app is saying I am 24 feet away. Then I fly 107 feet away and it says I am 19 feet from home, not 107 feet, but yet when I calculate the latitude and longitude it says I am 96 feet away
You can't install the Google Play version over the APK and vice versa. You have to uninstall first.
I Uninstalled and reinstalled and I still can't access that home option
Sounds like you aren't in the beta.
descargar en el siguiente enlace
download at the following link
https://support.dronelink.com/hc/en-us/articles/360033520874-How-do-I-install-the-beta-native-app-
I checked you are right. Ityped in v4 beta but it downloaded the regular one
After 2 attempts I finally got the Beta version loaded, and I have the option to change the distance reference but that does not correct for the error, or discrepancy, that is being reported as distance from home base or distance travelled. I can be right on top of home base but it says I am 12' away.
Hey Bob. I Hope I’m understanding your concern correctly. I posted a comment on the Beta thread yesterday about my drone. The new distance reference function when set in the Modern Dashboard to Home solved my big issues using my Wi-Fi only iPad. So far on several missions it’s been anywhere from about 6 feet to under a foot. To me that sounds accurate. It will never be perfect for several reasons and Jim has mentioned before they can be off by as much as + or - 4m. Not sure if that helps.. … 😬
I think sometimes the distance is sometimes more than Jim suggested and I seem to have problems with the quordinats. I will continue testing
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