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synching coordinate systems

August 26 2009 | 0 comments
Categories: Map Data

Hi,
Most of my layers are in NAD_1927_StatePlane_Texas_North_Central_FIPS_4202, but one layer is in GCS_North_American_1983. I have gone to the Data Frame Properties, then Coordinate System tab, then transformations, but the mismatched coordinate system doesn't seem to change. What am I doing wrong? Is there a better way to sync up my coordinate systems? Thanks.

Mapping Center Answer:

I am assuming that you have your data frame's coordinate system is set to:  NAD_1927_StatePlane_Texas_North_Central_FIPS_4202; and then the process of specifying the transformation will cause the GCS_North_American_1983 to align when it is drawn.  But, just specifying a transformation in the data frame will not actually change the GCS_North_American_1983 data.  You would need to use the Project tool to do that, which would create a new dataset.

If that GCS_North_American_1983 data is not aligning after you've specified the transformation in the data frame properties, there are other potential causes for that, including:

  1. That data may not have been projected properly to begin with, meaning there is an implied datum shift.  That's a hard one to work out because you would need to find the history of that dataset and learn how it was collected and projected.
  2. The data may have been collected from an independent source than your NAD27 data was collected--making it nearly impossible to expect alignment.

 

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