coordinate system

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

I have a flight to process from a UAV.  The ground control is defined in UTM 16N NAD83(2011) and NAVD88 (geoid12B) all in US survey feet.
I can import the images and control.  And run the process.

import limits me to WGS84 UTM 16 north egm96 ft

My output selection coordinate system is limted to WGS84 UTM16 north egm96 in ft

When I check the final surface and orthos they are shifted.  I believe the difference is international ft to us survey feet.

Can you tell me how to process my data  UTM 16N NAD83(2011) and NAVD88 (geoid12B) all in US survey feet and get the output I desire.

Thanks.

2

Hi Steve,

There are GCPs in UTM 16N NAD83(2011) and in NAVD88 (geoid12B)? the software does not support multiple coordinate systems for the GCPs.

Or did I misunderstand?

3

Well there is a vertical datum and a horizontal datum.  NAD83(2011) is the horizontal datum, the projection is UTM16, the units are US survey feet.  The vertical datum is NAVD88 the geoid model is (12B) and the units are US survey feet.  All my data is consistent in these datums, projections and units. 

The concern is that Pix4D does not define these items or units.  On import or export. 

So can you tell me how best to process my data in Pix4D to get accurate and consistent results in US survey feet.

What unit of feet is defined in Pix4D, i.e. international feet or US survey feet?

4

Sorry I misunderstood. When the coordinate system is in US sruvey feet, you see the symbol ftUS , otherwise you see ft for international feet.

To clarify the situation, there are three coordinate systems:

  • For the images: Written in the EXIF and automatically set by the software.
  • For the GCPs: Set by the user according to the GPS measurement device used on the field.
  • For the outputs: Set by the user depending on his needs.

By default the output coordinate system is:

  • The same as the one of the images without GCPs.
  • The same as the one of the GCPs if GCPs are included into the project.

However, the three coordinate systems can be different, meaning another output coordinate system can be selected independently from the geolocation reference of the images and the GCPs.

How to change coordinate system options: https://support.pix4d.com/hc/en-us/articles/202560029. To edit the vertical datum settings, check the box Advanced.

Regarding coordinate systems I also recommend this website that I find very helpful: http://spatialreference.org/.

Hope it answers your questions. If it remains unclear, please send me the quality report of the project (…\project_name\1_initial\report\project_name_report.pdf).