----------------------------Original message----------------------------
there is no magnetic declination annual change information published on
u.s. topo sheets. i used to have the same problem in trying to determine
what historical mag dec might have been for the purpose of reconstructing
old metes and bounds surveys. back in my ncic days i used to have a file
of data and maps from the (then) national geodetic survey. i think their
status may have changed over the last few years. one of the more
frustrating aspects of trying to piece this kind of information together
was that the average rate of change would change over fairly short
periods of time. you might try a web search for the ngs to see if they
have anything available online.
 
On Tue, 23 Jan 1996, Ben Moffat wrote:
 
> ----------------------------Original message----------------------------
> Help, please.
>
> I am dealing with the subject of magnetic declination and have been having a
> problem with some older US maps. Those that we have in our department are quite
> dated - usually the 1:24000, 1:62500, and 1:250000 series - some going back to
> the 1950s and 60s.
>
> On Canadian maps there is usually a statement such as "average annual
> magnetic chane 4' westerly" for example - that then makes figuring the
> contemporary position of mag north on the sheet rather easy....now the
> problem...
>
> I cannot find any such statement on the US maps. Are there look-up tables that
> have to be used, or am I missing something so obvious that it is about to make
> me feel really, really silly when I find out what it is...???
>
> Thanks in advance.
>
> Ben Moffat
> Geography - Medicine Hat College
> Medicine Hat, Alberta
>