hello everyone
I posted this on the Photoscan forum so I thought I'd post it here as well. Its for getting more accurate pre-processed elevation data out of the EXIF meta-data that might be useful for some on here. Improvements welcome of course. This is currently what works best for me but still a work in progress.
OBJECTIVE
For non-survey grade projects without using pre-sampled Ground Control Points, to get as accurate as possible elevation data prior to processing in Photoscan Pro. In other words to get the most accurate map/model/orthomossaic/DEM etc as possible without using RTK GPS.
PROBLEM
The usual metadata tag that is used by these applications is the ‘GPSaltitude’ tag. Currently DJI populate this from the aircraft's GPS unit. The altitude recorded here is grossly inaccurate. We need to fix this as far as we can.
BASIC WORKFLOW
We want to add this RelativeAltitude value to the calibrated barometer reading we took from our phone/device at take-off to come up with an altitude above sea level figure for each photograph.
Then we want to write this combined value into the GPSaltitude tag that Photoscan Pro can use.
thanks
I posted this on the Photoscan forum so I thought I'd post it here as well. Its for getting more accurate pre-processed elevation data out of the EXIF meta-data that might be useful for some on here. Improvements welcome of course. This is currently what works best for me but still a work in progress.
OBJECTIVE
For non-survey grade projects without using pre-sampled Ground Control Points, to get as accurate as possible elevation data prior to processing in Photoscan Pro. In other words to get the most accurate map/model/orthomossaic/DEM etc as possible without using RTK GPS.
PROBLEM
The usual metadata tag that is used by these applications is the ‘GPSaltitude’ tag. Currently DJI populate this from the aircraft's GPS unit. The altitude recorded here is grossly inaccurate. We need to fix this as far as we can.
BASIC WORKFLOW
- Establish and record the barometric altitude above mean sea level of your take-off point using an app.
- Back in the office we need to process the meta-data from all the photos taken poking a more accurate figure into the GPSaltitude tag.
We want to add this RelativeAltitude value to the calibrated barometer reading we took from our phone/device at take-off to come up with an altitude above sea level figure for each photograph.
Then we want to write this combined value into the GPSaltitude tag that Photoscan Pro can use.
thanks
