[OSM-talk] Coastline Update

[Andrew Errington]

On Sun, 01 Apr 2012 09:31:53 Clifford Snow wrote:
> On Fri, Mar 30, 2012 at 8:26 PM, Paul Norman <penorman at mac.com> wrote:
> > I have completed another coastline generation and it has uploaded. This
> > version respects odbl=clean.
> >
> > The shapefiles are in their normal place at
> > http://pnorman.dev.openstreetmap.org/coastlines/
> >
> > Included is a .osm file with all the error points.
> >
> > There are no significant multi-square flooded or dry areas. The following
> > areas have significant number of error points:
> >
> > Pudget Sound in Washington State
> >
> > I just pulled the osm file into josm.  I did a check of a couple of error
>
> points in the osm file in Puget Sound (Edmunds WA.)  They appear to be
> about 10+ meters from the shoreline according to the bing image.  Since I'm
> new at this, but since I live in the Puget Sound and would like to help fix
> it, what is an acceptable error distance?  Also - the bing image doesn't
> give a date and time to determine the tide level.  Or am I missing
> something?

Are you sure the Bing image is correctly aligned?  There is no guarantee that 
it is.  Find a bunch of GPS traces nearby for a road or other very visible 
feature and ensure they line up with that feature on the Bing image.  If they 
do, you're fine- use the Bing image to correct the coastline.  If they don't, 
then use the tools in Potlatch or JOSM to move the Bing layer into alignment 
*then* correct the coastline.

The coastline should follow the line of high tide.  Use your best judgement to 
determine this.  You're not missing something.

Best wishes,

Andrew