[OSM-newbies] Strange rectangular blue areas

[Helge Hafting]

topo at joelertola.com wrote:
> Thanks Jason.
>
>   I am still slightly worried that I may have caused a problem. To add  
> detail to the coast I deleted a whole section and redrew it. This  
> seemed easer than adding points to an existing coast and then moving  
> them. Later I seemed to have problems when I tried to delete more of  
> the coastline.  This coastline viewer map does not show my edits over  
> the last few days so I don't know if I accidentally left a hole in  
> Manhattan.
>   
I recommend loading the troubled section into JOSM, you can then
zoom in as much as needed, and look for accidental breaks.
A small break a few meters in size can be just as bad as a huge gap,
so don't leave even the tiniest break.

Also make sure the coastline goes in the correct direction.
A reversed section wil go wrong. Changing the direction is
easy, both in josm and potlatch. In josm, select the way and hit 'r'.
I think potlatch has a button for this.

> If you join two line segments that share both endpoints to form a  
> closed shape do both ends get joined? I was a little worried that only  
> one end would be joined leaving an undetectable break in the shape.
>   
If you join two ways then you get a closed shape. This is how you make
a lake or an island. Note that you don't have to join the ways into one
long way; the end node of one way can be the start node for the next way.
That works. If joining was necessary, then you'd need one continous way
around each continent, and that is too much data to work with.

Helge Hafting