From 85d45256efdc41f7245f87bb4ca63dbaf163705e Mon Sep 17 00:00:00 2001 From: Frank Warmerdam Date: Wed, 30 Nov 2005 17:03:54 +0000 Subject: Updated note on rotational parameters in 7 parameter transformation. git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@1314 4e78687f-474d-0410-85f9-8d5e500ac6b2 --- html/gen_parms.html | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/html/gen_parms.html b/html/gen_parms.html index 70824560..49529ebc 100644 --- a/html/gen_parms.html +++ b/html/gen_parms.html @@ -96,12 +96,8 @@ using an approximated 7 parameter transformation.

The seven parameter case uses delta_x, delta_y, delta_z, Rx - rotation X, Ry - rotation Y, Rz - rotation Z, M_BF - Scaling. The three translation parameters are in meters as -in the three parameter case. The rotational parameters are not in physical -units. They are something like the sine of the rotational angle times the -ellipoid axis length, but I don't know the exact details of how to derive -these from a physical description of the rotation. What I do know is that -they match the parameters used for transformation method 9606 in the EPSG -database. The scaling is apparently the scale change in parts per million.

+in the three parameter case. The rotational parameters are in seconds of +arc. The scaling is apparently the scale change in parts per million.

A more complete discussion of the 3 and 7 parameter transformations can be found in the EPSG database (trf_method's 9603 and 9606). Within PROJ.4 -- cgit v1.2.3