NAD_27_WGS84_CONUS transformation in Mobile Cache

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10-09-2014 01:05 PM
nagavijayasankaran
New Contributor

Hi,

 

Applying NAD_27_TO_WGS_84_conus  geotransformation does not get applied if a mobile cache is created. The Mapschema.bin fine has "Not Defined " for the transformation that is needed to go from NAD27 to WGS84 or vice versa. We have seen this issue for a while with  ArcGIS 9.X , 10.X as well.

Our research led to some 10 year old post where there is a quote from ESRI product specialist here:

 

 

ArcPad only supports three and seven parameter datum transformation methods. Unless you can calculate a local seven parameter transformation for your data, none of the predefined transformations are really that good. The best transformation is the NADCON method which uses two files of shift values to model the differences between NAD27 and NAD83. The files are generally too large to support on hand-helds.

 

ArcPad NAD27 issues with GPS (this is the link of the post).

 

 

Does it mean that ArcGIS Mobile products do not support NADCON based transformations in the Hand Held Devices? We work with pre-surveyed files where the points are already surveyed and transformed to a Projected coordinate System. Often the information about the specific Transformation that was applied to get to the X, Y is not available and navigating to these points are a challenge.

 

Has anybody seen this situation before where the mobile cache is generated with a CONUS transformation set up on the data frame, but the mobile cache does not carry this transformation and you are off by 100ft+ or whatever offset that is expected?

 

We are using ArcGIS 10.0, but I have tested that ArcGIS 10.2.X does not put CONUS transformation in the map cache as well?

 

Thanks,

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