BUG-000139221 for ArcGIS AppStudio

Bug ID Number	BUG-000139221
Submitted	April 21, 2021
Last Modified	June 5, 2024
Applies to	ArcGIS AppStudio
Version found	5.0
Operating System	Windows OS
Operating System Version	10.0 64 Bit
Status	Known Limit

Additional Information

The Projection Engine used by ArcGIS Runtime and other Esri products is frequently updated to improve its operation. A recent change is to deprecate an internal hardcoded choice of default transformations (which was difficult to maintain) in favor of an algorithm to choose the default transformation prioritizing coverage area of from and to spatial references, with accuracy as a tiebreaker where the coverage area is different. For MGI, covering Austria and former Yugoslavia, this results in the choice of MGI_To_WGS_1984 (1306) which covers a larger proportion of the area than the previous default of MGI_To_WGS_1984_3 (1618). Other available transformations have smaller coverage areas. Where the default transformation selected by this algorithm is not acceptable, change the default transformation used for a specific pair of spatial references by installing an overrides file and setting the projection engine location so that the file is used by ArcGIS Runtime. This process is described in https://developers.arcgis.com/qt/spatial-and-data-analysis/spatial-references/#customize-default-transformations. The following file content changes the default transformation for this specific case to the required MGI_To_WGS_1984_3 (1618): { "geogtran" : [ [ 4312, 4326, 1618, 0, 0, 0 ], ] } This default is used internally wherever geometries are transformed between these specific spatial references (excepting cases where particular transformation is specified, by calling GeometryEngine.project(Geometry, SpatialReference, DatumTransformation)).

Workaround

The issue is not reproducible if the two conditions are met:

The projection engine transformation files are downloaded on disk and are explicitly set in the app code - e.g. `Component.onCompleted: TransformationCatalog.projectionEngineDirectory = "file:///C:/Users/<username>/ArcGIS/Runtime/Data/PEDataRuntime"`
a gtdefaults_overrides.json file is created and placed in the PEDataRuntime location, with the below contents to specify the transformation to use:

{ "geogtran" : [

[ 4312, 4326, 1618, 0, 0, 0 ],

] }