[mkgmap-dev] Small contribution

Sun Feb 15 17:51:07 GMT 2009

On Feb 13, 2009, at 13:51, David wrote:
> As I am new here, I introduce myself.

Welcome!

> I am the author of a Garmin map made with the well known cgpsmapper.  
> I discovered OpenStreetMap few months earlier and I started to work  
> with mkgmap. My goal is to produce my map with mkgmap. I am not yet  
> ready because of these "problems" :
>
> - mkgmap cannot compile one of my big polygons even if I slice it  
> with mapedit.

Does mkgmap crash? Could you send the crash output and/or a small  
sample .mp-file?

> - mkgmap produces bigger files than cgpsmapper.

I think mkgmap is not very much optimised for small file size, but how  
large is the difference? Are you comparing maps generated from .mp for  
both tools?

> - derspite data come from OSM, routing does not work with my maps in  
> Mapsource (it is not a real problem, I cannot also do that with free  
> cgpsmapper).

Routing should now work. You need to use the "--route" option (but you  
appear to know that), and if you start with a .osm-file, you need to  
check out the nod branch from svn for the moment. What's going wrong  
for you?

> - mkgmap produces a different draw of the map when compiled with net  
> and route options : roads name appear and cities name are not  
> displayed in Mapsource.

Not sure what's wrong here. Anyone else see this?

> For mkgmap routing revision 856 and later :

I haven't looked at these modifications in detail, since I don't know  
those parts of the code too well. Regarding this:

> In the case I want to contribute to the code (to correct bugs or  
> activate functions for example), how can I do this ?

It would be best if you post your changes in patch form: Edit a local  
checkout of svn, then do "svn diff".

> As I was looking for why my contour lines and summits with altitude  
> in meters in my file (polish format .mp) are displayed in meters  
> divided by 3.2808399 (a feet to meters conversion) - is there a  
> setting to solve this ?

No idea... What does an entry for a contour line in a .mp-file look  
like? I would imagine mkgmap just writes a label, so it's surprising  
this should be wrong.

> - I found the function distance() where the earth is supposed to be  
> a sphere which is a pretty good approximation.

It should be good enough for our purposes.

Cheers
Robert