[OSM-newbies] Coastline Rendering

[Eric Ladner]

On Wed, Jul 9, 2008 at 11:53 PM, Zeke Farwell <ezekielf at gmail.com> wrote:
> Hi there fellow OSMers,
>

Technically, I think, you shouldn't use coastline for a lake, but
"natural=water".  Coastline is reserved for.. well.. the coast (or
typically areas affected by tidal forces which is where the great
lakes probably get a "costline" designation).  From the Wiki:
"natural=water is for inland lakes, and should not be used for tagging
ocean coastline. Equally natural=coastline should not be applied to
the edges of a lake."

This would force you to link all the outer ways into a single "outer"
way (clockwise), and all your internal islands into inner ways
(counterclockwise).

If it were me, I'd string as many of the outer ways together into one
continuous line (form a closed loop if you can) but the limit for the
number of nodes has been reported to be around 3000 to 5000 before
problems start occurring.  I've done ways with close to 2000 nodes
with no problems.

I've done a lot of stuff with rivers, riverbanks, islands, tidal
lowlands and such, but never a truly internal "lake", so, you might
have to fiddle with it a tad.

Even after you get your stuff done, unless you're running Tiles at Home
yourself, you have to wait till somebody actually renders the tile
before it shows up in the osmarender layer.  Dirty tiles can take up
to several days, I've seen, so I just started my own Tiles at Home at the
house to render on demand .  You can check and see when the tile was
last rendered if you go to informationfreeway.org, zoom in in to zoom
level 12, hover over the tile and hit the "i" key.  It'll open a
window showing you when the tile was last rendered.  The Mapnik layer
only updates once a week (or so).  You can also put it in the request
queue to get rendered with the "r" key in informationfreeway.org.  The
coastline viewer says it's about weekly, but there's red flags on
stuff I know I updated more than a week ago that still shows up.

If you're editing, don't worry about Mapnik so much.  If you get it to
look right in osmarender, when Mapnik DOES update, it'll be fine
(99.99% of the time).

-- 
Eric Ladner