Projection Issue With Custom Spatial Reference

sgn_GSI — Mon, 21 Jul 2025 16:19:14 GMT

My app is connecting to a web map where the customer's UN dataset is using a custom spatial reference. The resulting coordinate after projection is off a very small amount causing coincidence/connectivity to not occur.

Source:

Target:

The default datum transformation being returned and used for projection is the following:

- Input: {SpatialReference[Wkid=4269]}

- Output: {SpatialReference[Wkid=4326]}

- IsMissingProjectionEngineFiles = false

- Name: ~WGS_1984_(ITRF00)_To_NAD_1983

- Steps: 1

- WKText: GEOGTRAN["WGS_1984_(ITRF00)_To_NAD_1983",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],METHOD["Coordinate_Frame"],PARAMETER["X_Axis_Translation",0.9956],PARAMETER["Y_Axis_Translation",-1.9013],PARAMETER["Z_Axis_Translation",-0.5215],PARAMETER["X_Axis_Rotation",0.025915],PARAMETER["Y_Axis_Rotation",0.009426],PARAMETER["Z_Axis_Rotation",0.011599],PARAMETER["Scale_Difference",0.00062],OPERATIONACCURACY[0.1],METADATA["USA - CONUS and Alaska; PRVI",167.65,14.92,-63.88,74.71,0.0,0.0174532925199433,1511]]

- WKID: 108190

After using the default transformation, I am left with the following results:

- After Projection: X=-10656077.1980003, Y=3392011.73970032

- Expected Value: X=-10656077.2082, Y=3392011.728

- X Value Difference: 0.010199720039963722

- Y Value Difference: 0.011700315400958061

- Esri Feet Default Buffer: 0.003281

My experience with spatial references and datum transformations is lacking so I'm not sure if my issue is with the custom spatial reference my client is using OR if I need to define and use a custom transformation. Any advice would be greatly appreciated.

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Projection Issue With Custom Spatial Reference