Mounted search and rescue

["Marie Lester" <marie.lester@gmail.com>]

Even though our unit begins exercises with a reminder that each GPS
should be set on WGS84 map datum, another issue that needs to be
resolved is that all participants set thier GPS units on the same
Lat/Lon Coordinates.  (DEG/MIN/MM,  DEG/MIN/MMM, DEG/MIN/SEC,
DEG.DDDD)  We have noted, however, that Garmins and Magellans do not
have exactly the same options.  This is one factor that contributes to
such discrepancies in location.  Our observations are that operator
error, receiver capability in each unit, and circumstance affect
accuracy as well.

Marie Lester
COMSU


On 2/27/07, Charles L. Sparke <clsnv@sbcglobal.net> wrote:
> First guess is that the person laying out the course was using one map datum
> (probably NAD27 or WGS84) and the rest were using the other one.  In my area
> (northern Nevada) the difference is about 100 meters east-west and about 15
> north-south)  in other parts of the US it could well be that far off.
>
>  Remember, unless you've got access to military maps, most civilian
> available maps are still gridded using NAD27 map datum.  Aircraft and never
> military (1985 on) are gridded using WGS84.  If you're plotting, be sure to
> match the map datum on your GPS to the map you are using.
>
>  Charles Sparke
>  Pershing County SAR
>  Lovelock, NV
>
> _______________________________________________
> MSAR-Riders mailing list
> MSAR-Riders@lists.ibiblio.org
> http://lists.ibiblio.org/mailman/listinfo/msar-riders