[Proj] EPSG and ToWGS84

[Markus Neteler]

On Tue, Apr 20, 2004 at 01:59:21PM +0900, proj-admin at remotesensing.org wrote:
> Hello All,
> Please can anyone help me find the ToWGS84 values for a datum in
> the EPSG database?
> 
> I have being playing with the EPSG database but still could not find
> the ToWGS84 parameters anywhere!

The SQL query should be something like this (I received this
SQL statement from an EPSG team member):

SELECT o.coord_op_name, m.coord_op_method_name, p.parameter_name,
pu.sort_order, pv.parameter_value, u.unit_of_meas_name, a.area_name
FROM epsg_coordoperation o
JOIN epsg_coordoperationmethod m
ON m.coord_op_method_code = o.coord_op_method_code
JOIN epsg_coordoperationparamvalue pv
ON pv.coord_op_method_code = o.coord_op_method_code AND
pv.coord_op_code = o.coord_op_code
JOIN epsg_coordoperationparamusage pu
ON pu.coord_op_method_code = o.coord_op_method_Code AND
pu.parameter_code = pv.parameter_code
JOIN epsg_coordoperationparam p
ON p.parameter_code = pv.parameter_code
JOIN epsg_unitofmeasure u
ON u.uom_code = pv.uom_code
JOIN epsg_area a
ON a.area_code = o.area_of_use_code
WHERE o.coord_op_type = 'transformation' AND o.coord_op_name 
LIKE '%WGS 84%' AND o.deprecated = 0
ORDER BY coord_op_name;

Best regards,

 Markus