Incorrect results of GeometryEngine.Project for EPSG:31468 in 10.2.6

Question

Hello,

I recently updated our runtime Version from 10.2.4 to 10.2.6. Now there is a incorrect projection from EPSG:31468 to EPSG:4326.

Example:

var mappoint = new MapPoint(4594314.825,5821864.005, new SpatialReference(31468));

var projectedMappoint = GeometryEngine.Project(mappoint, new SpatialReference(4326));

Result 10.2.4:

var mappoint = {MapPoint[X=4594314.825, Y=5821864.005, Wkid=31468]}

var projectedMappoint = {MapPoint[X=13.3880091660746, Y=52.5217421380065, Wkid=4326]}

Results 10.2.6 & 10.2.7:

var mappoint = {MapPoint[X=4594314.825, Y=5821864.005, Wkid=31468]}

var projectedMappoint = {MapPoint[X=13.3897513416898, Y=52.5231506263074, Wkid=4326]}

I doublechecked the result on different websites and my results is, the calculation in the new version is not correct any more.

Can anybody please check this for me or give me a hint, where I can open a support ticket.

Thanks a lot!

SalieghAziz · Answer

Try using ArcGIS for Server's Geometry Service's project end point. You have more control with it as it allows you to specify the geotransformation parameters rather than depending on the runtime to select some default for you. Alternatively, you can use the service without the datum transformation and direction parameters, and it would assume these for you (although I've always supplied them when i know a transformation is required)

OliverBrandt2 · Answer

Hello,

could you find out anything? Currently I am using a third party library for projecting. This is definitely a bug.

Is it possible to force the runtime using the transformation? This would help me.

Cheers

Oli

EzraT_2-1713963553040.png

OliverBrandt2 · Answer

Hello Mike,

Both apps are running on the same machine. I only changed the runtime Version for investigating the false map placement. My System is a Windows 7 x64. We are using Visuals Studio 2012 for developing.

It's definitely the different version of the runtime.

My example from above:

var mappoint = new MapPoint(4594314.825,5821864.005, new SpatialReference(31468));

var projectedMappoint = GeometryEngine.Project(mappoint, new SpatialReference(4326));

await _MapView.SetViewAsync(mappoint, 2000);

This code snippet should be enough to reproduce the differnt results.

The differences are only a few hundred meters.

Cheers

Oliver