Hello and thank you in advance.
I am still, unfortunately, a little confused on the projection for posting data in Google Earth:
I understand that GE and MS apps use a spheroid only model, which is the projection ESRI calls:
Geographic Coordinate System, (spheroid-based) "GCS_WGS 1984 Major Auxiliary Sphere" or
Projected Coordinate System (World) "WGS_1984_Web_Mercator"
Whereas ESRI uses a spheroid or ellipsoid model, which is the projection ESRI calls:
Geographic Coordinate System (World) "GCS_WGS_1984" or
Projected Coordinate System (World) "WGS_1984_Web_Mercator (Auxiliary Sphere)"
The instructions in Technical Article ID: 34749 say when using 9.3 SP1 to use the:
Predefined Projected Coordinate System (World) "WGS_1984_Web_Mercator"
HERE IS MY PROBLEM:
When projecting from NAD83 to Projected WGS_1984_Web_Mercator in the toolbox,
there is a message that this is an undefined projection, and I can only do it with a
double: NAD_1983_To_WGS_1984_5 AND WGS_1984_Major _Auxiliary_Sphere_To_WGS_1984
The same is true (obviously) if I try to project from NAD83 to Geographic GCS_WGS_1984_Major_Auxiliary_Sphere
Isn't this exactly the same as just going from NAD_1983_To_GCS_WGS_1984, which is the ESRI model,
not the Google Earth or MS (Bing) model, right?
In the end, projecting to GCS_WGS_1984 is equivalent to
projecting to PCS_WGS_1984_Web_Mercator which is equivalent to
projecting to GCS_WGS_1984_Major_Auxiliary_Sphere
The only difference is that the denominator of the flattenting ratio for the PCS_WGS_1984_Web_Mercator is infinity
instead of 298.257224. No matter what, the locations lie directly on top of one another and NOT where I can
see them (my well points) on the Google Earth image.
So, how do folks line up their very locatlized point locations on a Google Earth visualization for their projects/clients?
In addition, using the double transform to get to
Projected Coordinate System (World) "WGS_1984_Web_Mercator"
yields the same projected or local bounding coordinates as
Projected Coordinate System (World) "WGS_1984_Web_Mercator (Auxiliary Sphere)"
HOWEVER, Google Earth will not import the file "WGS_1984_Web_Mercator (Auxiliary Sphere)" (says zero features)
Why does this happen?
HELP!!
Nicki Cook