Trimming Map Tiles

[baredj]

 I would like to trim map tiles in the California Topo to be more specific to my needs and improve the redraw speed of my Etrex when panning. Also it would reduce the unnecessary downloaded file size to my minimalistic Venture HC.  Is that possible in either MapSource, BaseCamp or some other way perhaps?

[Seldom]

In order to change the tile size you need to compile a new map.  Not possible with any of the viewers you list.  If you think it's worth the trouble, here's the place to start.

http://www.gpsfiledepot.com/tutorials/how-to-create-garmin-topo-maps/

[baredj]

Wow! You're Right. That's a lot of work. I'm no computer geek but wouldn't it be neat to have a tool program that you could transfer your chosen map file to from MapSource and crop and trim there before downloading to the GPS unit?

[maps4gps]

Easiest solution would be to replace that ancient GPSr with a new model; which also have many additional features and capabilities.