NAD27->NAD83

[Gillian Bowser]

>I have grass dig files of soil lines based on the NAD27..what is the most
>appropriate way to get those file to the NAD83 to match my NAD83 digital
>orthos...are there software programs that already exist that will help me
>in this procedure...v.transform ..lt4x...arcinfo...
>will consider all possibilities..and appreciate any help or direction to
>proceed.  

>Thanks
>Pam Smith
>NRCS

I am also curious--as I understand, if you don't add additional control
points, then the NAD27 is still limited by the underlying reference
surface which would be Clark66 instead of geodectic (reference for
NAD83).  Is this true??  Do you gain/lose any accuracy by dropping the
NAD83 to match the Clark66 and is that easier than finding new control
points to bring the NAD27 up to geodectic reference surface?

Gillian Bowser
National Park Service
Denver, Colorado