Phantom 4 Pro Altitude issue, DJI geotags problem

PIX4Dcapture
1

Hi, I’m using a Phantom 4 Pro in a planed mision, I have a problem with the altitud recorded on the jpg files, it is wrong, totally diferent than expected for that area, even in two flights of the same place is diferent, I try to take pictures with DJI GO APP and the altitud recorded is totally diferent than the altitud recorded with Pix4d Capture. I’m sure that the altitud recorded by Pix 4d is the one that is wrong.

Can you help?

Thaks

2

tengo el mismo problema pero con un p3p.

3

Amplío la descripción del problema en español, por ejemplo hice un vuelo a 100 m de altura (desde el despegue) en una zona donde la altura GPS de las fotos a 100 m de altura de vuelo debería haber andado en el entorno de los 165 m y la altura que se grabo en los jpg fue mas o menos 4 metros el primer día de vuelo y 40 metros el segundo día, en la misma zona con la misma altura de vuelo.

Agradezco cualquier dato que me puedan aportar.

4

Hola Enrique.

Por favor confirma la anomalía detectada en cuanto a los datos que suministras.

As far as I understand, please confirm the information provided:

  1. Take-off GPS altitude ( Home ): 100 m. 
  2. Mission altitude (relative to Home ): 65 m.
  3. EXIF GPS altitude (expected): ~165 m.
  4. EXIF GPS altitude recorded day # 1: 4 m.
  5. EXIF GPS altitude recorded day # 2: 40 m.

Paste the photos properties like this:

Saludos / The best!

Federico.

5

Hola, muchas gracias por la respuesta, corrijo el 1 y el 2 que quedaron al revés, además adjunto captura de las propiedades de una de las imágenes.

  1. Take-off GPS altitude ( Home ): 65  m. 
  2. Mission altitude (relative to  Home ):  100 m.
  3. EXIF GPS altitude (expected): ~165 m.
  4. EXIF GPS altitude recorded day # 1: 4 m.
  5. EXIF GPS altitude recorded day # 2: 40 m.

 

6

Hi,

This is a known issue with the way DJI geotags and we have noticed the same in multiple mission. 

To give some more insight, the images that are saved on the drone’s SD card are geotagged by DJI. Lat./Long. coordinates are reliable in the image EXIF, however, there might be some inaccuracies for the altitude depending on the location where you are mapping. We made testing in our office here and we found that the vertical coordinate is off by several meters that can reach an error of 100 meters. Some users noticed the same. Note that this is just an offset meaning that within the model, the accuracy is not affected, only the absolute location is. 

As a consequence, we always recommend processing with ground control points (GCPs) in order to fix these uncertainties. If you have issues to mark the GCPs in the rayCloud because of vertical shift, click here. If you do not have GCPs, please refer to this procedure.

Best,

7

The same thing happened to me with a Phantom 3 STD, I flew at an approximate MSL height of 114 m, and in the image JPG registered a height of 19 m, the subject that when orienting the photographs the flight was curved, which could be the problem guide the photographs?
Thanks for the reply and forgiveness for the translation.