Hi Harlan...

As Bruce mentioned, you need to know the precise lat/lon for at least
three locations in the map. In my case, I had similar USGS maps that
were already calibrated. So it was just a matter of finding the same
locations in each map, then using the USGS map to determine what the
lat/lon positions were and giving GPSPro that same information for
each position.

The free marine charts won't have support available, unfortunately.
Check out the website and see if the charts you need are available. I
don't know if I can assist with calibration. I might be able to make
some suggestions to assist, however.

By the way, just one posting and I got a half dozen spam with this
email address. Fortunately this particular email address is
"disposable". Those anti-spam safeguards are definitely worthwhile.

Dean.

Bruce in Alaska wrote in message ...
In article ,
Harlan Lachman wrote:

Dean thanks for trying to be helpful. Could you explain in a little
more detail what you mean. Sorry I am so ill informed.

What does it mean to need to calibrate a chart (why, how, what skills)?
Why would I want these charts if they are not useful to GPSPRo? Where
does onge get a calibrated USGS map that can work with GPSPro?

Will the provider of those charts have a person available by phone to
help guide one in using their charts for the first time?

TIA,

Harlan