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LIDAR-derived raster not matching up with other raster- Different Datums?

Question asked by dav22b on Aug 7, 2014

Hello all,

 

I am working on a land cover change analysis; I recently created a canopy cover raster with the following projection info:

 

NAD_1927_UTM_Zone_11N

WKID: 26711 Authority: EPSG

 

 

Projection: Transverse_Mercator

False_Easting: 500000.0

False_Northing: 0.0

Central_Meridian: -117.0

Scale_Factor: 0.9996

Latitude_Of_Origin: 0.0

Linear Unit: Meter (1.0)

 

 

Geographic Coordinate System: GCS_North_American_1927

Angular Unit: Degree (0.0174532925199433)

Prime Meridian: Greenwich (0.0)

Datum: D_North_American_1927

  Spheroid: Clarke_1866

    Semimajor Axis: 6378206.4

    Semiminor Axis: 6356583.799998981

    Inverse Flattening: 294.9786982

 

I received LIDAR-derived DSM's and DTM's for the same area but from a later year with the following projection info:

 

WGS_84_UTM_zone_11N

Authority: Custom

 

 

Projection: Transverse_Mercator

false_easting: 500000.0

false_northing: 0.0

central_meridian: -117.0

scale_factor: 0.9996

latitude_of_origin: 0.0

Linear Unit: Meter (1.0)

 

 

Geographic Coordinate System: GCS_WGS_1984

Angular Unit: Degree (0.0174532925199433)

Prime Meridian: Greenwich (0.0)

Datum: D_WGS_1984

  Spheroid: WGS_1984

    Semimajor Axis: 6378137.0

    Semiminor Axis: 6356752.314245179

    Inverse Flattening: 298.257223563

 

When I imported the new DTM's and DSM's, the layers were slightly off (by about 80 meters or so). I edited the spatial reference information in ArcCatalog and the layers still did not match up. I used the Project Raster tool and the layers still did not match up. I used the Define Projection tool and the layers still did not match up.

 

Any ideas on why these two datasets are not matching up? What should I do?

 

Thanks!

David

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