[mkgmap-dev] [PATCH] alpha patch (V3) for simplifying ways and reducing img size

Sun Apr 12 21:27:16 BST 2009

On Feb 27, 2009, at 3:43 PM, Johann Gail wrote:

> Ok, here follows V3 of my patch. Needs some small code cleanup but  
> works fine for now.

Are you still working on this patch?

I've tried it out on a number of maps: I could get compression levels  
similar to what you describe (about a 10% reduction in size). I had  
also hoped that this would improve display performance of the maps,  
but I could not detect any noticeable change.

On my eTrex when I zoom out to scales of 50 or 80 km, it can take a  
very long time for the device to draw the map. From my observation of  
the way the map is drawn, it seems like the highways are drawn segment  
by segment.

As you have stated, a perhaps more effective approach would be first  
to join highway segments where possible (for example by merging  
bridges and tunnels, neither of which are displayed by the Garmin  
devices), and then to apply the Douglas-Peucker algorithm to these  
longer segments. Do you have any idea how this could be achieved?

Cheers.