[mkgmap-dev] Overview map for Africa

Thu Mar 28 13:03:18 GMT 2013

> Gerd wrote:
>> yes, that is caused by a missing if statement:
>> if (!finfo.isImg())
>> return;
>
> Thanks,
>
> And how about points, like big cities, country and sea names, are they copied too to the overview map?
> I think a special style file for generating the overview map is better.
> If possible with a few zoomlevels, like Felix suggested. If no such style is present, mkgmap will look at the items in the lowest level that is present, like the patch now does.

What about the following ideas:

1. Retrieve the data from the highest instead of the lowest level. The 
lowest level often contains fragmentary data, e.g. have a look a the 
boundaries in your example image 
http://gis.19327.n5.nabble.com/file/n5754697/africa_overview.png
The data could be merged so that long ways are created that do not fall 
through the filters (DouglasPeucker etc.). The MapReader.linesForLevel 
and other methods must have filters that returns only selected garmin id 
types.

2. Use a separate overview style file and fetch the Garmin ids out of 
it. Then use these Garmin ids to build the overview map. I think the 
overview map should be configurable (one likes to see motorways, others 
like to see rivers etc.)
Maybe it would also be possible to add a special overview statement or 
use special overview levels in the normal style files to achieve the same.

3. In case --precomp-sea parameter is set the data from an additional 
file in the precompiled sea folder is used.

WanMil