CREATE COORDINATE SYSTEM FROM XML LOCALIZATION FILE

[dhobbsMBJTR]

I have an xml localization file.

I wish to create a geodetic coordinate system, projected into the local system. The transformation parameters and co-located points are contained in the xml file.

I know I have to create a wgs84 to local transformation, just not sure how to go about it!

Thanks

[Pointdump]

Hi Daniel,
I don't think MAPCSLIBRARY has anything in it that can handle ECEF (Earth Centered Earth Fixed) coordinates. Is your data in ECEF?
More details please on what kinds of data you're working with, and what you want to do.
Dave

[dhobbsMBJTR]

Hi Steve

Thanks for coming back to me. The xml file has ECF coordinates, paired with "system" coordinates, see attached.

I can convert the WGS ECF coordinates into WGS84 Lat, Long, h if required.

I need to create a Local Projection (SF=1) of this system whilst preserving it's geodetic relationship.

I am pretty sure the key is to create a transformation defined by the parameters in the XML file.

I am not sure on the workflow. I assume:

1. Create a local TM projection based on WGS84 datum with Central Meridian per the localization data 

<TransverseMercatorProjection falseE="0" falseN="0" lambda0="138.32330003837902" phi0="-34.50056142609715" zoneWidth="6" scale0="1" />

2. Define a transformation between WGS84 and local using a Helmert2DTransformation, per the xml file

<Helmert2DTransformation rotation="-1.2433362091134907" rotationOriginalX="-0.00032153795473277569" rotationOriginalY="2.4058301026030904E-05" shiftdX="6142512.4763215389" shiftdY="275275.xxx-xxxxxxxx" scale="0.99993803352200061" transformationModel="molodensky" />

[Pointdump]

Daniel,
Yes, I read through the XML and the PDF, and saw the pairings and Transverse Mercator definition.
Defining a custom TM projection is not a problem, but the Helmert transformation is. I don't know whether that is to be used on the ECEF-to-Geographic CS, or to transform WGS-to-MGA2020 datums.
Do you have other data that would tie the custom projection to UTM?
You might also want to post this question on the >>>Stack Exchange GIS Forum<<<.
Dave

[dhobbsMBJTR]

Hi @Pointdump 

The localization was performed on a data collector and exported to XML format. I suspect Leica Infinity. The surveyor also provided me with a .dc (Trimble Access Export) file and a .lok file (Carlson SurvCE).

I believe the transformation definition is ECEF to Local. Disregard the MGA20 note from the control sheet. The coordinates are not MGA. MGA projection has a scale factor of 0.9996, which these coordinates don't reflect.

I'll post to StackExchange.

Thanks