[OSM-dev] Extracting polygons from planet.osm - take 2

[Keith Sharp]

On Fri, 2007-03-16 at 10:11 +0000, Robert Hart wrote:
> > I would appreciate it if people could try this out and let me know if
> it
> > works, and is accurate!  If people think this is valuable I would like
> > to create directory in SVN for both the script and a collection of
> > polygon files, I am happy to oversee this.  I would also like to
> create
> > a Wiki page describing the script usage and polygon files.
> 
> Keith, 
> 
> Not had time to run this yet, but I read the code, so here's some things
> I thought of along the way:
> 
> Line 106:
> 
> if ($compress > 99) {
> 
> Shouldn't that be ($compress < 99)?

Thanks for pointing this out, actually it was completely wrong, it
should be:

	if (($compress > 0 && $compress < 100) && $pol->nrPoints > 99)

Only accept percentage values of 1-99 and only reduce if the number of
points in the polygon is 100 or more.

> Line 171:
> 
> if ($used_nodes->{$2} || $used_nodes->{$3})
> 
> Wouldn't it be better to only output segments with both nodes defined?
> i.e. && instead of ||

I have to admit this part is a copy and paste from Frederiks original so
I'll have to leave to him to comment :-)

> Of course, you are making all the usual assumptions about the structure
> of the OSM file, but I think that's an acceptable compromise for users
> of your script.

Sure, it might be worth adding a OSM file version check to the script in
the hope that if the structure changes the version will be bumped.

Thanks for the feedback,

Keith.