New Oregon 450 & Topo 100K

[hamilgs]

New Oregon 450 user here, and I’m still in basic learning mode. On the advice of a friend I purchased US Topo 100K, and have the portions I frequent (SE US) loaded. The friend also has SE US Topo 24K.  The 24K will route, turn by turn from A to B, but over the same route, 100K will not, the error message is “Route calculation error: Maps do not have routable roads in this area”.

Does that suggest that I can’t route using Topo 100K, or does that suggest “operator error” which is my usual problem. I had planned to buy City Navigator, but have not done so yet.

Note we each have the maps loaded on to a micro SD card, and we have been swapping cards to compare features of the map sets, and the 450 Vs Etrex Vista hcx.

[mdxix]

Your experience is correct with the current map releases:

• Topo 100k does not provide route calculation. See product feature that it "Contains roads, trails and highways in metropolitan and rural areas" without mention of the key word "routable". Meanwhile, I had posted earlier instructions for use of free Open Street Maps.
• Topo 24k does provide route calculation. See example Southeast route from Garmin. It "Contains routable roads, trails and highways in metropolitan and rural areas".