[gdal-dev] Datum transformation method when projecting from a sphere to NAD83 shapefile

[Limei Ran]

Hi:

I am using ogr2ogr to project a shapefile defined in a sphere to NAD83.  
My command is like the following:

ogr2ogr -t_srs "+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 
+x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs " -s_srs 
"+proj=lcc +a=6370000.0 +b=6370000.0 +lat_1=33 +lat_2=45 +lat_0=40 
+lon_0=-97" wrf12km_nc_g152.shp wrf12km_nc.shp

Could you tell me which datum transformation method is used during 
projecting?  In arcGIS there are many selections such as geocentric 
method, NADCON method and others.

Thank you,

Limei