Scale Factor and Projection Issues

AmandaBednarz — Wed, 26 Mar 2014 18:25:41 GMT

Hello,

Hopefully I can describe the issue appropriately. I have received a geodatabase with feature classes developed from LiDAR data that was processed in Microstation. I know very little about what has been done to the data through this process but the files I do have are in the following projection:

NAD_1983_StatePlane_Idaho_East_FIPS_1101_Feet
WKID: 2241 Authority: EPSG

Projection: Transverse_Mercator
False_Easting: 656166.6666666665
False_Northing: 0.0
Central_Meridian: -112.1666666666667
Scale_Factor: 0.9999473684210526
Latitude_Of_Origin: 41.66666666666666
Linear Unit: Foot_US (0.3048006096012192)

Geographic Coordinate System: GCS_North_American_1983
Angular Unit: Degree (0.0174532925199433)
Prime Meridian: Greenwich (0.0)
Datum: D_North_American_1983
Spheroid: GRS_1980
    Semimajor Axis: 6378137.0
    Semiminor Axis: 6356752.314140356
    Inverse Flattening: 298.257222101

Everything looks good except they do not align with basemap imagery or other shapefiles in the same projection. Everything is approximately 200 ft to the NE or where it should be. Attached is an image of the alignment.

1) Is this a scale factor issue? How can I find the appropriate scale factor? I have shapefiles of similar data processed from the same lidar data that align without issue. The defined projection is the same in the shapefiles as the geodatabase.
2) Is this an issue with the processing within Microstation and any suggestions on how to fix it?
3) Are there any resources available that go into detail about the appropriate workflow from Mobile LiDAR data collection to CAD or MicroStation and then ArcGIS?

Thank you for any input on this issue.

Re: Scale Factor and Projection Issues

MelitaKennedy — Thu, 27 Mar 2014 22:39:15 GMT

No idea if this is related, but is this data DGN? And are you using 10.2.1? Or what version are you using? As reported in another thread, there's a bug with DGN files that is causing the data to be offset in ArcGIS. It's related to the global origin in the file. If there's an offset applied, it's getting read and used in ArcGIS. Tech Support told me that one solution is to convert the data to DWG. I assume removing the offset in the global origin would work too.

Normally the offset is large, so it might not explain your 200 meters.

Melita

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Scale Factor and Projection Issues

Re: Scale Factor and Projection Issues