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OSTN15 / OSGM15

Hi there,

Can we have full support of the national mapping coordinate system of the UK; OSTN15 / OSGM15 please.

Not a work around, just the correct transformation procedure as dictated by the Ordnance Survey.

Hello there,
This is something that I need help with. I am flying a Sensefly Ebee X in RTK mode (using Trimble VRSnow). When importing images into Pix4dMapper, my Trimble support guy says that, at the ‘add image’ stage, I need to copy the WGS84 coords out to a folder and the run them through GridInquest so they can then be re-imported. I’m not clear on this - if I’m flying in RTK, why can’t the OS national grid coords (Ea/No) be downloaded & used? I carry out ground surveys using a Trimble R6 in RTK mode and this is exactly what I do there. Appreciate if anyone could walk me through this.
Thanks

Hi @andrew.parsons , Your Trimble support is correct. You should export you image positions during this stage using the To File… button in the Image properties Editor, then use GridinQuest II to transform your image positions and then re-import into Pix4D using the From File… button in the same Image Properties Editor window, being sure to select OSGB36 and arbitrary as the coordinate system reference.

Pix4Dmapper does not support the OSTN15 or OSGM15 transformation models that will be on your R6, hence this step has to be completed in GridInQuest II. If you need any assistance, please get in touch with us at

jason@geodronesurvey.com

www.geodronesurvey.com.

Hi @mja and @andrew.parsons ,

As @Jason_Hagon mentions, PIX4Dmapper does not support grid transformations, which are those required to accurately transform your project’s Image Geolocation Coordinate System (WGS84) to your project’s Output Coordinate System before processing your project. When RTK geotags are used, this type of transformation is needed to preserve the RTK accuracy. PIX4Dmapper also does not directly support geoids.

Therefore the workaround is to convert your horizontal and vertical image geotags in third-party software before importing them for processing, define the output horizontal coordinate system as needed and the output vertical coordinate system as arbitrary.

More information about the topic can be found at these links:
Horizontal grid corrections and transformations
How to define Pix4D outputs with respect to a geoid model
Select Image / GCP / Output coordinate system

PIX4Dmatic does instead support grid transformations and local geoids.