On 5 Sep 2009, at 9:15 , Steve Ratcliffe wrote:
Hi Mark
On 05/09/09 11:44, Mark Burton wrote:
Playing with my shiny new Nuvi 255, I notice that it can route across
an OSM map of the UK pretty well. It can find long routes
reasonably quickly. In comparison, mapsource 6.13.6 often fails to
determine a route at all and when it does it is rather slow about it.
Previously someone claimed that on mapsource you needed a routable
basemap to get good inter-tile routing, but that on a GPS device you
don't. As the basemap is not sent to the device that makes sense.
Not sure about Mapsource. Roadmap for Mac has the basemap. But still
routing doesn't work as good as on the Vista. Wild guess the Vista
uses the basemap but Roadmap doesn't.
On the other hand the device may already have a routable base map
and so
perhaps it uses that if it has one and is the source of the
observation.
I know that on my Legend Cx which does not have a UK base map I do not
get very good routing across tiles.
does anyone know how to disable the basemap on a Vista?
Another wild guess can it be that Garmin adjusts the basemap names/
boundary nodes .... with their map products on tile boundaries to help
routing?
Really disabling is impossible. What is possible to flash a non
routable US Basemap which you include in firmware. To go back do the
same for the european basemap.